Reference

NAT L INST. OF STAND & TECH

NBS

Publications

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NBS SPECIAL PUBLICATION 260-71

U.S. DEPARTMENT OF COMMERCE / National Bureau of Standards

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1981

Standard Reference Materials:

SUMMARY OF THE CLINICAL

LABORATORY STANDARDS ISSUED BY THE

NATIONAL BUREAU OF STANDARDS
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards' was established by an act of Congress on March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology

and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in

trade, and (4) technical services to promote public safety. The Bureau's technical work is per- formed by the National Measurement Laboratory, the National Engineering Laboratory, and

the Institute for Computer Sciences and Technology.

THE NATIONAL MEASUREMENT LABORATORY provides the national system of

physical and chemical and materials measurement; coordinates the system with measurement

systems of other nations and furnishes essential services leading to accurate and uniform

physical and chemical measurement throughout the Nation's scientific community, industry,

and commerce; conducts materials research leading to improved methods of measurement,

standards, and data on the properties of materials needed by industry, commerce, educational

institutions, and Government; provides advisory and research services to other Government

agencies; develops, produces, and distributes Standard Reference Materials; and provides

calibration services. The Laboratory consists of the following centers:

Absolute Physical Quantities2 — Radiation Research — Thermodynamics and

Molecular Science — Analytical Chemistry — Materials Science.

THE NATIONAL ENGINEERING LABORATORY provides technology and technical services to the public and private sectors to address national needs and to solve national

problems; conducts research in engineering and applied science in support of these efforts; builds and maintains competence in the necessary disciplines required to carry out this research and technical service; develops engineering data and measurement capabilities;

provides engineering measurement traceability services; develops test methods and proposes

engineering standards and code changes; develops and proposes new engineering practices;

and develops and improves mechanisms to transfer results of its research to the ultimate user. The Laboratory consists of the following centers:

Applied Mathematics — Electronics and Electrical Engineering2 — Mechanical

Engineering and Process Technology2 — Building Technology — Fire Research —

Consumer Product Technology — Field Methods.

THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts

research and provides scientific and technical services to aid Federal agencies in the selection,

acquisition, application, and use of computer technology to improve effectiveness and

economy in Government operations in accordance with Public Law 89-306 (40 U.S.C. 759),

relevant Executive Orders, and other directives; carries out this mission by managing the

Federal Information Processing Standards Program, developing Federal ADP standards

guidelines, and managing Federal participation in ADP voluntary standardization activities; provides scientific and technological advisory services and assistance to Federal agencies; and

provides the technical foundation for computer-related policies of the Federal Government.

The Institute consists of the following centers:

Programming Science and Technology — Computer Systems Engineering.

'Headquarters and Laboratories at Gaithersburg, MD, unless otherwise noted; mailing address Washington, DC 20234.

2 Some divisions within the center are located at Boulder, CO 80303.
Standard Reference Materials:

SUMMARY OF THE CLINICAL LABORATORY STANDARDS ISSUED BY

THE NATIONAL BUREAU OF STANDARDS

Office of Standard Reference Materials

National Measurement Laboratory

National Bureau of Standards

Washington, DC 20234

and

R. Mavrodineanu 1

Center for Analytical Chemistry

National Measurement Laboratory

National Bureau of Standards

Washington, DC 20234

'Present Address: 227 Almeria Road

West Palm Beach, FL 33405

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

R. W. Seward

fU<J(xJ fiJjJU

Issued November 1981
Library of Congress Catalog Card Number: 81-600149

National Bureau of Standards Special Publication 260-71

Nat. Bur. Stand. (U.S.), Spec. Publ. 260-71, 176 pages (Nov. 1981)

CODEN: XNBSAV

i

1

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1981
Preface

Standard Reference Materials (SRM's) as defined by the National Bureau of Standards

are well-characterized materials, produced in quantity and certified for one or more

physical or chemical properties. They are used to assure the accuracy and compatibility

of measurements throughout the Nation. SRM's are widely used as primary standards in many

diverse fields in science, industry, and technology, both within the United States and

throughout the world. They are also used extensively in the fields of environmental and

clinical analysis. In many applications, traceability of quality control and measurement

processes to the national measurement system is carried out through the mechanism and use of SRM's. For many of the Nation's scientists and technologists it is therefore of more

than passing interest to know the details of the measurements made at NBS in arriving at

the certified values of the SRM's produced. An NBS series of papers, of which this

publication is a member, called the NBS Special Pub! i cation - 260 Series , is reserved for

this purpose.

This 260 Series is dedicated to the dissemination of information on different phases of

the preparation, measurement, certification and use of NBS-SRM's. In general, much more

detail will be found in these papers than is generally allowed, or desirable, in scientific

journal articles. This enables the user to assess the validity and accuracy of the

measurement processes employed, to judge the statistical analysis, and to learn details of

techniques and methods utilized for work entailing the greatest care and accuracy. These

papers also should provide sufficient additional information not found on the certificate

so that new applications in diverse fields not foreseen at the time the SRM was originally

issued will be sought and found.

Inquiries concerning the technical content of this paper should be directed to the

author(s). Other questions concerned with the availability, delivery, price, and so forth,

will receive prompt attention from:

Office of Standard Reference Materials

National Bureau of Standards

Washington, D. C. 20234

George A. Uriano, Chief

Office of Standard Reference Materials
OTHER NBS PUBLICATIONS IN THIS SERIES

Catalog of NBS Standard Reference Materials

(1979-80 edition), R. W. Seward, ed., NBS

Spec. Publ. 260 (April 1979) $3.00* SN003-003-

02048-6

Michaelis, R. E., and Wyman, L. L., Standard

Reference Materials: Preparation of White Cast

Iron Spectrochemical Standards, NBS Misc.

Publ. 260-1 (June 1964). COM74-1 1061**

Michaelis, R. E., Wyman, L. L., and Flitsch, R.,

Standard Reference Materials: Preparation of

NBS Copper-Base Spectrochemical Standards,

NBS Misc. Publ. 260-2 (October 1964). COM74-

11063**

Michaelis, R. E., Yakowitz, H., and Moore, G. A.,

Standard Reference Materials: Metallographic

Characterization of an NBS Spectrometric LowAlloy Steel Standard, NBS Misc. Publ. 260-3

(October 1964). COM74-1 1060**

Hague, J. L., Mears, T. W., and Michaelis, R. E.,

Standard Reference Materials: Sources of

Information, NBS Misc. Publ. 260-4 (February

1965). COM74-1 1059

Alvarez, R., and Flitsch, R., Standard Reference

Materials: Accuracy of Solution X-Ray Spectrometric Analysis of Copper-Base Alloys, NBS

Misc. Publ. 260-5 (March 1965). PB 168068**

Shultz, J. I., Standard Reference Materials:

Methods for the Chemical Analysis of White

Cast Iron Standards, NBS Misc. Publ. 260-6

(July 1975). COM74-11068**

Bell, R. K., Standard Reference Materials:

Methods for the Chemical Analysis of NBS

Copper-Base Spectrochemical Standards, NBS

Misc. Publ. 260-7 (October 1965). COM74-

11067**

Richmond, M. S., Standard Reference Materials:

Analysis of Uranium Concentrates at the

National Bureau of Standards, NBS Misc. Publ.

260-8 (December 1965). COM74-1 1066**

Anspach, S. C, Cavallo, L. M., Garfinkel, S. B.,

Hutchinson, J. M. R., and Smith, C. N., Standard Reference Materials: Half Lives of Materials

Used in the Preparation of Standard Reference

Materials of Nineteen Radioactive Nuclides

Issued by the National Bureau of Standards,

NBS Misc. Publ. 260-9 (November 1965).

COM74-11065**

Yakowitz, H., Vieth, D. L., Heinrich, K. F. J., and

Michaelis, R. E., Standard Reference Materials:

Homogeneity Characterization on NBS Spectrometric Standards II: Cartridge Brass and LowAlloy Steel, NBS Misc. Publ. 260-10 (December

1965). COM74- 11064**

Napolitano, A., and Hawkins, E. G., Standard

Reference Materials: Viscosity of Standard

Lead-Silica Glass, NBS Misc. Publ. 260-11

(November 1966). NBS Misc. Publ. 260-11**

Yakowitz, H., Vieth, D. L., and Michaelis, R. E.,

Standard Reference Materials: Homogeneity

Characterization of NBS Spectrometric Standards III: White Cast Iron and Stainless Steel

Powder Compact, NBS Misc. Publ. 260-12

(September 1966). NBS Misc. Publ. 260-12**

Spijkerman, J. L., Snediker, D. K., Ruegg, F. C,

and DeVoe, J. R., Standard Reference Materials: Mossbauer Spectroscopy Standard for the

Chemical Shift of Iron Compounds, NBS Misc.

Publ. 260-13 (July 1967). NBS Misc. Publ.

260-13**

Menis, O., and Sterling, J. T., Standard Reference

Materials: Determination of Oxygen in Ferrous

Materials - SRM 1090, 1091, and 1092, NBS

Misc. Publ. 260-14 (September 1966). NBS Misc.

Publ. 260-14**

Passaglia, E., and Shouse, P. J. Standard Refer- ence Materials: Recommended Method of Use

of Standard Light-Sensitive Paper for Calibrating Carbon Arcs Used in Testing Textiles for

Colorfastness to Light, NBS Misc. Publ. 260-15

(June 1967). (Replaced by NBS Spec. Publ.

260-41.)

Yakowitz, H., Michaelis, R. E., and Vieth, D. L.,

Standard Reference Materials: Homogeneity

Characterization of NBS Spectrometric Standards IV: Preparation and Microprobe Characterization of W-20% MO Alloy Fabricated by

Powder Metallurgical Methods, NBS Spec.

Publ. 260-16 (January 1969). COM74-1 1062**

Catanzaro, E. J., Champion, C. E., Garner, E. L.,

Marinenko, G., Sappenfield, K. M., and Shields,

W. R. Standard Reference Materials: Boric

Acid; Isotopic and Assay Standard Reference

Materials, NBS Spec. Publ. 260-17 (February

1970). Out of Print

IV
Geller, S. B., Mantek, P.A., and Cleveland, N.

G., Standard Reference Materials: Calibration of NBS Secondary Standard Magnetic Tape

(Computer Amplitude Reference) Using the

Reference Tape Amplitude Measurement

"Process "NBS Spec. Publ. 260-18 (November

1969). (See NBS Spec. Publ. 260-29.)

Paule, R. C, and Mandel, J., Standard Reference

Materials: Analysis of Interlaboratory Measurements on the Vapor Pressure of Gold (Certification of Standard Reference Material 745). NBS

Spec. Publ. 260-19 (January 1970). PB190071**

Paule, R. C, and Mandel, J., Standard Reference

Materials: Analysis of Interlaboratory Measurements on the Vapor Pressures of Cadmium and

Silver, NBS Spec. Publ. 260-21 (January 1971).

COM74-11359**

Yakowitz, H., Fiori, C. E., and Michaelis, R. E.,

Standard Reference Materials: Homogeneity

Characterization of Fe-3 Si Alloy, NBS Spec.

Publ. 260-22 (February 1971). COM74-1 1357**

Napolitano, A., and Hawkins, E. G., Standard

Reference Materials: Viscosity of a Standard

Borosilicate Glass, NBS Spec. Publ. 260-23

(December 1970). COM7 1-00 157**

Sappenfield, K. M., Marineko, G., and Hague, J.

L., Standard Reference Materials: Comparison

of Redox Standards, NBS Spec. Publ. 260-24

(January 1972). COM72-50058**

Hicho, G. E., Yakowitz, H., Rasberry, S. D., and

Michaelis, R. E., Standard Reference Materials:

A Standard Reference Material Containing

Nominally Four Percent Austenite, NBS Spec.

Publ. 260-25 (February 1971). COM74-1 1356**

Martin, J. F., Standard Reference Materials:

National Bureau of Standards-US Steel Corportion Joint Program for Determining Oxygen and

Nitrogen in Steel, NBS Spec. Publ. 260-26

(February 1971). 85 cents* PB 81176620

Garner, E. L., Machlan, L. A., and Shields, W. R.,

Standard Reference Materials: Uranium

Isotopic Standard Reference Materials, NBS

Spec. Publ. 260-27 (April 1971). COM74-

11358**

Heinrich, K. F. J., Myklebust, R. L., Rasberry, S. D., and Michaelis, R. E., Standard Reference

Materials: Preparation and Evaluation of

SRM's 481 and 482 Gold-Silver and GoldCopper Alloys for Microanalysis, NBS Spec.

Publ. 260-28 (August 1971). COM7 1-50365**

Geller, S. B., Standard Reference Materials: Calibration of NBS Secondary Standard Magnetic

Tape (Computer Amplitude Reference) Using

the Reference Tape Amplitude Measurement

"Process A-Model 2," NBS Spec. Publ. 260-29

(June 1971). COM71-50282

Gorozhanina, R. S., Freedman, A. Y., and

Shaievitch, A. B. (translated by M. C. Selby),

Standard Reference Materials: Standard

Samples Issued in the USSR (A Translation

from the Russian). NBS Spec. Publ. 260-30 (June

1971). COM71-50283**

Hust, J. G., and Sparks, L. L., Standard Reference

Materials: Thermal Conductivity of Electrolytic

Iron SRM 734 from 4 to 300 K, NBS Spec. Publ.

260-31 (November 1971). COM7 1-50563**

Mavrodineanu, R., and Lazar, J. W., Standard

Reference Materials: Standard Quartz Cuvettes,

for High Accuracy Spectrophotometry, NBS

Spec. Publ. 260-32 (December 1973). 55 cents*

SN003-003-01213-1

Wagner, H. L., Standard Reference Materials:

Comparison of Original and Supplemental

SRM 705, Narrow Molecular Weight Distribution Polystyrene, NBS Spec. Publ. 260-33

(May 1972). COM72-50526**

Sparks, L. L., and Hust, J. G., Standard Reference

Materials: Thermoelectric Voltage, NBS Spec.

Publ. 260-34, (April 1972). COM72-50371**

Sparks, L. L., and Hust, J. G., Standard Reference Materials: Thermal Conductivity of

Austenitic Stainless Steel, SRM 735 from 5

to 280 K, NBS Spec. Publ. 260-35 (April 1972.)

35 cents* COM72-50368**

Cali, J. P., Mandel, J., Moore, L. J., and Young, D.

S., Standard Reference Materials: A Referee

Method for the Determination of Calcium in

Serum, NBS SRM 915, NBS Spec. Publ. 260-36

(May 1972). COM72-50527**

Shultz, J. I s

Bell., R. K,, Rains, T. C, and Menis,

O., Standard Reference Materials: Methods of

Analysis of NBS Clay Standards, NBS Spec.

Publ. 260-37 (June 1972). COM72-50692**

Richmond, J. C, and Hsia, J. J., Standard Refer- ence Materials: Preparation and Calibration of

Standards of Spectral Specular Reflectance,

NBS Spec. Publ. 260-38 (May 1972). COM72-

50528**

Clark, A. F., Denson, V.A., Hust, J. G., and

Powell, R. L., Standard Reference Materials

The Eddy Current Decay Method for Resistivity

Characterization of High-Purity Metals, NBS

Spec. Publ. 260-39 (May 1972). COM72-50529**
McAdie, H. G., Garn, P.D.,and Menis, O., Standard Reference Materials: Selection of Thermal

Analysis Temperature Standards Through a Cooperative Study (SRM 758, 759, 760), NBS

Spec. Publ. 260-40 (August 1972.) COM72-

50776**

Wood, L. A., and Shouse, P. J., Standard

Reference Materials: Use of Standard LightSensitive Paper for Calibrating Carbon Arcs

Used in Testing Textiles for Colorfastness to Light, NBS Spec. Publ. 260-41 (August 1972)

COM72-50775**

Wagner, H. L. and Verdier, P. H., eds., Standard

Reference Materials: The Characterization of

Linear Polyethylene, SRM 1475, NBS Spec.

Publ. 260-42 (September 1972). COM72-

50944**

Yakowitz, H., Ruff, A. W., and Michaelis, R. E.,

Standard Reference Materials: Preparation and

Homogeneity Characterization of an Austenitic

Iron-Chromium-Nickel Alloy, NBS Spec. Publ.

260-43 (November 1972). COM73-50760**

Schooley, J. F., Soulen, R. J., Jr., and Evans, G. A.,

Jr., Standard Reference Materials: Preparation

and Use of Superconductive Fixed Point

Devices, SRM 767, NBS Spec. Publ. 260-44

(December 1972). COM73-50037**

Greifer, B., Maienthal, E. J.j Rains, T. C, and

Rasberry, S. D., Standard Reference Materials:

Powdered Lead-Based Paint, SRM 1579, NBS

Spec. Publ. 260-45 (March 1973). COM73-

50226**

Hust, J. G., and Giarratano, P. J., Standard Refer- ence Materials: Thermal Conductivity and

Electrical Resistivity Standard Reference Materials: Austenitic Stainless Steel, SRM's 735 and

798, from 4 to 1200 k, NBS Spec. Publ. 260-46

(March 1975). SN003-003-0 1278-5

Hust, J. G., Standard Reference Materials: Electrical Resistivity of Electrolytic Iron, SRM 797,

and Austenitic Stainless Steel, SRM 798, from 5

to 280 K, NBS Spec. Publ. 260-47 (February

1974). COM74-50176**

Mangum, B. W., and Wise, J. A., Standard Refer- ence Materials: Description and Use of Precision

Thermometers for the Clinical Laboratory,

SRM 933 and SRM 934, NBS Spec. Publ. 260-48

(May 1974). 60 cents* SN003-003-0 1278-5

Carpenter, B. S., and Reimer, G. M., Standard

Reference Materials Calibrated Glass Standards for Fission Track Use, NBS Spec. Publ.

260-49 (November 1974). COM74-5 1185

vi

Hust, J. G., and Giarratano, P. J., Standard Refer- ence Materials: Thermal Conductivity and Electrical Resistivity Standard Reference Materials:

Electrolytic Iron, SRM's 734 and 797 from 4 to 1000 K, NBS Spec. Publ. 260-50 (June 1975).

$1.00* SN003-003-0 1425-7

Mavrodineanu, R., and Baldwin, J. R., Standard

Reference Materials: Glass Filters As a Standard

Reference Material for Spectrophotometry;

Selection; Preparation; Certification; Use-SRM

930, NBS Spec. Publ. 260-51 (November 1975).

$1.90* SN003-003-01481-8

Hust, J. G., and Giarratano, P. J., Standard Refer- ence Materials: Thermal Conductivity and Electrical Resistivity Standard Reference Materials

730 and 799, from 4 to 3000 K, NBS Spec. Publ.

260-52 (September 1975). $1.05* SN003-003-

01464-8

Durst, R. A., Standard Reference Materials:

Standardization of pH Measurements, NBS

Spec. Publ. 260-53 (December 1975, Revised).

$1.05 SN003-003-01551-2

Burke, R. W., and Mavrodineanu, R. Standard

Reference Materials: Certification and Use of

Acidic Potassium Dichromate Solutions as an

Ultraviolet Absorbance Standard, NBS Spec.

Publ. 260-54 (August 1977). $3.00* SN003-003-

01828-7

Ditmars, D. A., Cezairliyan, A., Ishihara, S., and

Douglas, T. B., Standard Reference Materials:

Enthalpy and Heat Capacity; Molybdenum

SRM 781, from 273 to 2800 K, NBS Spec. Publ.

260-55 (September 1977). $2.20* SN003-003-

01836-8

Powell, R. L., Sparks, L. L., and Hust, J. G.,

Standard Reference Materials: Standard

Thermocouple Materials, Pt.67: SRM 1967, NBS

Spec. Publ. 260-56 (February 1978). $2.20*

SN003-003-0 18864

Cali, J. P. and Plebanski, T., Guide to United

States Reference Materials, NBS Spec. Publ.

260-57 (February 1978). $2.20* PB 277173

Barnes, J. D., and Martin, G. M., Standard Refer- ence Materials: Polyester Film for Oxygen Gas

Transmission Measurements SRM 1470, NBS

Spec. Publ. 260-58 (June 1979) $2.00* SN003-

003-02077

Chang, T., and Kahn, A. H., Standard Reference

Materials: Electron Paramagentic Resonance

Intensity Standard: SRM 2601, NBS Spec.

Publ. 260-59 (August 1978) $2.30* SN003-

003-01975-5
Velapoldi, R. A., Paule, R. C, Schaffer, R.,

Mandel, J., and Moody, J. R., Standard Refer- ence Materials: A Reference Method for the

Determination of Sodium in Serum, NBS Spec.

Publ. 260-60 (August 1978). $3.00* SN003-003

01978-0

Verdier, P. H., and Wagner. H. L., Standard Refer- ence Materials: The Characterization of Linear

Polyethylene (SRM 1482, 1483, 1484), NBS

Spec. Publ. 260-61 (December 1978). $1.70*

SN003-003-02006-1

Soulen, R. J., and Dove, R. B., Standard Reference

Materials: Temperature Reference Standard

for Use Below 0.5 K (SRM 768). NBS Spec.

Publ. 260-62 (April 1979). $2.30* SN003-003-

02047-8

Velapoldi, R. A., Paule, R. C, Schaffer, R.,

Mandel, J., Machlan, L. A., and Gramlich, J. W.,

Standard Reference Materials: A Reference

Method for the Determination of Potassium in

Serum. NBS Spec. Publ. 260-63 (May 1979).

$3.75* SN003-003-02068

Velapoldi, R. A., and Mielenz, K. D., Standard

Reference Materials: A Fluorescence Standard

Reference Material Quinine Sulfate Dihydrate

(SRM 936), NBS Spec. Publ. 260-64 (January

1980). $4.25* SN003-003-02 148-2

Marinenko, R. B., Heinrich, K. F. J., and Ruegg,

F. C, Standard Reference Materials: MicroHomogeneity Studies of NBS Standard Reference

Materials, NBS Research Materials, and Other

Related Samples, NBS Spec. Publ. 260-65

(September 1979). $3.50* SN003-003-021 14-1

Venable, W. H., Jr. and Eckerle, K. L., Standard

Reference Materials: Didymium Glass Filters for

Calibrating the Wavelength Scale of Spectrophotometers (SRM 2009, 2010, 2013), NBS Spec.

Publ. 260-66 (October 1979). $3.50* SN003-003-

02127-0

Velapoldi, R. A., Paule, R. C, Schaffer, R., Mandel,

J., Murphy, T. J., and Gramlich, J. W., Standard

Reference Materials: A Reference Method for the

Determination of Chloride in Serum, NBS Spec.

Publ. 260-67 (November 1979). $3.75* SN003-

003-02136-9

Mavrodineanu, R. and Baldwin, Jr., Standard

Reference Materials: Metal-On-Quartz Filters as a Standard Reference Material for Spectrophotometry-SRM 2031, NBS Spec. Publ. 260-68

(April 1980). $4.25* SN003-003-02 167-9

Velapoldi, R. A., Paule, R. C, Schaffer, R.,

Mandel, J., Machlan, L. A., Garner, E. L., and

Rains, T. C, Standard Reference Materials: A

Reference Method for the Determination of

Lithium in Serum, NBS Spec. Publ. 260-69 (July)

1980). $4.25* SN003-003-02214-4

Marinenko, R. B., Biancaniello, F., Boyer, P. A.,

Ruff, A. W., DeRobertis, L., Standard Reference

Materials: Preparation and Characterization of

an Iron-Chromium-Nickel Alloy for Microanalysis, NBS Spec. Publ. 260-70 (May 1981).

$2.50*

Seward, R. W., and Mavrodineanu, R.,, Standard

Reference Materials: Summary of the Clinical

Laboratory Standards Issued by the National

Bureau of Standards, NBS Spec. Publ. 260-71

(in press).

Reeder, D.J., Coxon, B., Enagonio, D., Christensen,

R. G., Schaffer, R., Howell, B. F., Paule, R. C,

Mandel, J., Standard Reference Materials: SRM

900, Antiepilepsy Drug Level Assay Standard,

NBS Spec. Publ. 260-72 (June 1981). $4.25*

* Send order with remittance to Superintendent

of Documents, US Government Printing Office,

Washington, DC 20402. Remittance from

foreign countries should include an additional

one-fourth of the purchase price for postage. ** May be ordered from: National Technical

Information Services (NTIS), Springifield,

Virginia 22151.

vii
TABLE OF CONTENTS

PAGE

Preface iii

Abstract iv

Introduction 1

Table 1. Categories of Standard Reference Materials available from the

National Bureau of Standards 2

Clinical Laboratory Standards 4

Table 2. Summary of Clinical Laboratory Standards 6

A. Organics 6

B. Organo-Metallic 12

C. Inorganic 14

D. Ion-Activity

.

16

E. Temperature 18

F. Spectrophotometry and Fluorescence 18

1. Solids 18

2. Liquids and Cuvettes 20

3. Stray Light 22

4. Wavelength 22

5. Fluorescence 24

Table 3. NBS Publications in the "260 Series" Related to Clinical Chemistry 26

Appendices 27

Appendix I. Alphabetical Index of SRM's 27

Appendix II. Certificates for Clinical Laboratory Standards 35

(listed in numerical order)

vi i i
Abstract

This publication is a summary of the Clinical

Laboratory Standards issued by NBS as Standard

Reference Materials (SRM's). The material, composition, certification, use, and remarks concerning

each of the SRM's described are presented in tabular

form. Copies of the certificates for these SRM's

are contained in the appendix for more detailed

information.

Key Words: Chemical composition; clinical materials; Standard Reference Materials.

ix

Introduction

Since its inauguration in 1901, the National Bureau of Standards (NBS) has issued

nearly 2000 different Standard Samples or Standard Reference Materials (SRM's). Many of

these have been renewed several times, many have been replaced or discontinued as technology

changed. Today, over 1000 SRM's are available, together with a large number of scientific

publications related to the fundamental and applied characteristics of these materials.

Each material is certified for chemical composition, chemical properties, or its physical

or mechanical characteristics. Each SRM is provided with a Certificate or Certificate of

Analysis that contains the essential data concerning its properties or characteristics.

The SRM's currently available cover a wide range of chemical, physical, and mechanical

properties, and a corresponding wide range of measurement interests in practically all

aspects of fundamental and applied science. These SRM's constitute a unique and invaluable

means of transferring to the user accurate data obtained at NBS, and provide essential tools

that can be used to improve accuracy in practically all areas where measurements are performed.

In addition to SRM's, the National Bureau of Standards issues a variety of Research

Materials (RM's) having various properties described in individual "Reports of Investigation". They are intended primarily to further the scientific or technical research on that

particular material. Other materials, called Special Reference Materials (GM's), are also

available from NBS. These are material s, produced and certified by other Government agencies,

standard organizations, or other nonprofit organizations, that are considered useful to the

public and for which no alternate method of national distribution exists.

The various categories of materials available from NBS are given in Table 1. This

lists these materials according to their chemical composition, physical properties, or engineering characteristics. A more detailed alphabetic enumeration of these materials is

given in Appendix I. Table 1 and Appendix I were taken from NBS Special Publication 260,

NBS Standard Reference Materials Catalog, 1979-80 Edition 2

. This publication lists every

material available from the NBS Office of Standard Reference Materials.

Further information on the reference materials available from NBS may be obtained from

the Office of Standard Reference Materials, National Bureau of Standards, Washington, D. C. 20234. Information on other NBS services may be obtained from the Technical Information

and Publications Division, National Bureau of Standards, Washington, D. C. 20234.

In addition to these types of materials, NBS provides many additional services. These

include: Measurement Assurance Programs, Calibration and Related Measurement Services,

Proficiency Sample Programs, a National Voluntary Laboratory Accreditation Program,

Standards Information Services, Standard Reference Data, and Technical Information and

Publ ications.

2 For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington,

D. C. 20402, under Stock No. 003-003-20248. (Price $3.00, add 25 percent for foreign

orders.

)

1
Table 1. Categories of Standard Reference Materials available from the National Bureau

of Standards.

CERTIFIED CHEMICAL

Steels (chip form)

Plain carbon

Low alloy

High alloy

Stainless

Tool

Steels (granular form)

Steels (solid form)

Ingot iron and low alloy

Special ingot irons and low alloy

Stainless

Special ty

High- temperature alloys

Tool

Steelmaking Alloys

Cast Irons (chip form)

Cast Steels, White Cast Irons, Ductile

Irons, and Blast Furnace Irons

(solid form)

Nonferrous Alloys (chip form)

Aluminum "Benchmarks"

Cobalt

Copper

Copper "Benchmarks"

Lead

Magnesium

Nickel

Nickel Superalloy, Trace Elements

Nickel oxide

Sel enium

Tin

Titanium

Zinc

Zirconium

Nonferrous Alloys (solid form)

Aluminum "Benchmarks"

Copper

Copper "Benchmarks"

Lead

Nickel

Titanium

Zinc

Zirconium

COMPOSITION STANDARDS

Gases in Metals

High-Purity Metals

Electron Probe Microanalytical Standards

Primary, Working, and Secondary

Standard Chemicals

Microchemical Standards

Clinical Laboratory Standards

Biological Standards

Environmental Standards

Analyzed gases

Analyzed liquids and solids

Permeation tubes

Industrial Hygiene Standards

Forensic Standards

Hydrocarbon Blends

Metallo-Organic Compounds

Fertil izers

Ores

Minerals, Refractories, Glasses, and

Carbides

Cement

Trace Element Standards

Nuclear Materials

Special nuclear materials

Plutonium assay

Plutonium isotopic

Uranium assay

Uranium isotopic

Neutron density standards

Fission track glass standards

Isotopic Reference Standards

2
Table 1 . continued.

CERTIFIED PHYSICAL PROPERTY STANDARDS

Ion Activity Standards

pH standards

pD standards

Ion selective electrodes

Mechanical and Metrology Standards

Magnification

Coating thickness

Glass

Elasticity

Density

Polymer

Rheology

Heat Standards

Superconductive thermometric fixed

point devices

Freezing points

Defining fixed points

Determined reference points

Melting points

Calorimetric

Combustion

Sol ution

Heat source Enthalpy and heat capacity

Vapor pressure

Thermal expansion

Thermocouple materials

Thermal resistance

Magnetic Standards

Magnetic susceptibility

Magnetic moment

Paramagnetic resonance

ENGINEERING

Standard Rubber and RubberCompounding Materials

Reference Magnetic Tapes

Centerline Drawings, OCR-B

Sizing Standards

Glass spheres for particle size

Turbidimetric and fineness (cement)

RESEARCH MATERIALS

Optical Standards

Spectrophotometric

Thermal emittance

Refractive index

Radioactivity Standards

Alpha-particle standards

Beta-particle and gamma-ray gas

standards

Alpha-particle, beta-particle, gammaray, and electron-capture solution

standards

Contemporary standard for carbon-14

dating laboratories

Environmental standards

Low energy photon sources Gamma-ray "point-source" standards

Radium gamma-ray solution standards

Radium solution standards for randon

analysis

Radioactivity standard reference

materials currently not in stock

Metal 1 urgical

Mossbauer

X-ray Diffraction

Gas Transmission

Permittivity

Reference Fuels

Resistivity

TYPE STANDARDS

Color Standards

X-ray and Photographic Standards

Surface Flammability Standards

Smoke Density Chamber Standards

Water Vapor Permeance

Tape Adhesion Testing Standard

SPECIAL REFERENCE MATERIALS
Clinical Laboratory Standards

The first NBS Standard Reference Material designed specifically for clinical laboratory

use was issued in December 1967. This standard, SRM 911, Cholesterol, was developed in

response to requests from both the College of American Pathologistsand the American Association for Clinical Chemistry. In the 12 years since then, the number of clinical SRM's has

grown to 30, and has been supplemented by new spectrophotometry and temperature standards

that are also useful in the clinical field. During the next decade this growth is expected

to continue at much the same rate.

The SRM's produced (and those planned), especially since 1973, have closely followed

the priority list for clinical SRM's established in 1973 by the NBS Analytical Chemistry

Division3 Clinical Chemistry Advisory Panel.

This publication is an attempt to describe in general terms the composition, certification, and use of the clinical laboratory SRM's and those other SRM's especially useful in

such laboratories. No attempt has been made, however, to include all of the SRM's that may

be used in clinical laboratories, e.g., primary chemicals, pH standards, etc., nor has an attempt been made to list other possible uses for these materials. Many of them would

have applications in general analytical laboratories and in laboratories where the accuracy

of molecular absorption spectrometry is of primary interest.

Table 2 contains the essential information concerning the material composition, the

certification parameters, and use. Under "Remarks," additional data such as storage

conditions and stability is provided. 4 All the data and information contained in this

table were extracted from the Certificates or Certificates of Analysis issued for the

SRM's included in the table, except those SRM's listed as "In Preparation". An examination

of this table gives the reader a general view of these SRM's. For more detailed information, the individual Certificates reproduced in Appendix II should be consulted as well as the references cited in each Certificate.

In the table, similar types of SRM's are grouped together to facilitate comparisons

of their properties. This should prove especially useful for the spectrophotometry SRM's

where both wavelength range and material composition are critical to the user. The

Certificates in Appendix II, however, are arranged in numerical order. The SRM's listed in

the table include all of the clinical laboratory standards that were issued or were in

preparation by the end of 1979. These SRM's are the result of the concerted efforts of more than 70 scientists from the NBS National Measurement Laboratory. Each Certificate

lists the individuals who contributed to the certification of the SRM.

In addition to the SRM's and their Certificates, NBS issues a series of Special

Publications (SP), called the "260 Series," that relate directly to Standard Reference

Materials as stated in the preface. The list of available publications in the "260 Series"

is given at the beginning of this publication. 5

3 Now the Center for Analytical Chemistry.

4 N0TE: The use of proprietary designations in Table 2 is for information only, and should

not be construed as an endorsement of the product by either the Department of Commerce or

the National Bureau of Standards.

5 For complete bibliographic reference and ordering information, see "Other Publications in

this Series," pp. VII-X.

4
Several of these publications describe the certification or use of SRM's listed in

Table 2, and several others deal with methodology important to clinical laboratories.

Table 3 matches the publication number to the related SRM number and gives an abbreviated

title for the publication. Planned publications in this series of clinical interest are also listed in the table.

5
Table 2. Summary of Clinical Laboratory Standards

A. Organics

SRM Material Composition

900

Antiepliepsy Drug

Level Assay

Standard

A mixture of 4 antiepilepsy

drugs in a processed human serum base. The material

was processed, vialed, and

packaged by Microbiological

Associates, Wal kersvi 1 le,

Maryland.

SRM 900 contains concentration levels of the 4 drugs

at the toxic, therapeutic,

and subtherapeutic levels,

in pg/mL for phenytoin

ethosuximide, phenobarbi tal

,

and primidone, respectively,

are: 60.7, 16.7, and 4.2;

174.7, 75.9, and 11.8;

103.6, 21 .6, and 5.3; and

18.6, 8.1, and 3.6.

909

Human Serum

In preparation at time of writing. Certificate will be

included in Appendix B if available at time of publication.

910

Sodium Pyruvate

In preparation at time of writing. Certificate will be

included in Appendix B if available at time of publication.

911a

Cholesterol

Cholesterol of known purity.

The material was obtained

from J. T. Baker Chemical

Company, Phi 11 ipsburg,

New Jersey.

Purity is 99.8%. Test for

lathosterol is negative.

Melting point is 149.0 to

149.4 °C. Specific rotation

[a]20 is -0.700 rad (-40.1°)

(c,l ; CHC1 3

) . Carbon

83.86±0.05 wt.%; hydrogen

12.00±0.05 wt.%. Loss at

100 °C and 0.02 torr is

0.01% per hour over 1.5

day period.

912a

Urea

Urea of known purity. The

material was obtained from

Fluka AG, Switzerland

Purity is 99.9%; moisture is

0.02%; biuret is 0.02%; ash

is 0.001%; insoluble matter

is 0.0001. The inaccuracy

for the value of purity is

estimated to be 0.1%.

Melting range is 133.0 to

134.0 °C. A 10% aqueous

solution of urea showed a pH of 7.1±0.2 at 23 °C.

6
Certification Use Remarks

The analytical techniques

used in the certification

were liquid and gas chromagraphy. Immunoenzymatic

assays have also been used.

The certification uncertainties, at one standard error, were from ±0.1 to ±0.9 y/mL

according to the compound

and the concentration.

For the calibration of clincal procedures for the

determination of these 4

components in serum and for

the evaluation of reference

solutions prepared in house

or supplied commercially.

For "in vitro" diagnostic

use only. For use, the

materials should be recon- stituted with high-purity

water, and this solution

used within 1 day.

SRM 900 must be handled as

if capable of transmitting

hepatitis. It is supplied

in a set of 4 individual

freeze-dried preparations

that should be stored at

4 °C in the dark. Under

these conditions the

material is stable for 2 years.

The purity was determined by

liquid chromatography;

gravimetric recovery; thinlayer chromatography; gas

chromatography; neutron

activation; infrared and

ultraviolet absorption

spectrometry. Two

impurities were found

representing a combined

weight of 0.08% of the

initial sample. Bromine

content is 12 yg/g; chlorine

content is 0.7 yg/g; iodine

content is less than 0.8

yg/g ±20%.

For the calibration and

standardization of procedures for cholesterol

determinations in clinical

analysis and for evaluation

of daily working standards.

For "in vitro" diagnostic

use only. Stock standard

solutions are prepared by

dissolving in absolute

ethanol (5 mmol/L)

.

The solutions should be

cl ear.

Cholesterol should be stored

in tightly closed bottles in

a refrigerator or freezer,

protected from sun or ultraviolet radiation. When

stored under inert gas, as delivered, and at -15 °C the

material is stable for 10

years. If stored in the

dark at room temperature the

material should not be used

after 6 months from the date

of purchase. The 5-mmol/L

ethanol solution at 0 °C is

stable for 4 months; the

2. 5-mmol/L acetic acid

solution at room temperature

is stable for 3 months.

The apparent purity was determined by differential

scanning calorimetry.

Biuret was estimated

spectrophotometrically

.

Moisture was determined

by the Karl Fischer

titration.

For the calibration and

standardization of procedures for urea nitrogen

determinations in clinical

analysis and for evaluation of daily working

standards. For "in vitro"

diagnostic use only. A

standard solution containing

20 mg/100 mL of urea nitrogen is prepared from 0.429 g urea in 1000 mL of ammoniafree distilled water.

Urea should be stored in its

tightly closed container to

prevent change in the

moisture content. It should

not be exposed to heat,

moisture, or direct sun- light. Refrigerated storage

is recommended. Under

proper storage urea is

stable for at least 5 years.

The standard urea nitrogen

solution (20 mg/100 mL) is

stable for 3 months when

stored at 4 °C in a well

stoppered, all-glass

contai ner.

7
Table 2. A. Organics - continued.

SRM Material Composi tion

913

Uric Acid

Uric acid of known purity.

The material was obtained

from the Pfanstiehl

Laboratories , Inc .

,

Waukegan, Illinois.

Purity is 99.7%; volatile

matter is 0.14%; ash is

0.057%. Purity is given

with an estimated

inaccuracy of 0.1%. The

ash contains : Na , K, Al

,

Ca , Fe, P, Si , Co , Cu , Mn

,

Ni, Zn.

914

Creatinine

Creatinine of known

purity. The material

was obtained from the

Pfanstiehl Laboratories,

Inc., Waukegan, Illinois,

Purity is 99.8%; volatile

matter is 0.03%; chloride

is 0.07%; ash is 0.003%;

insoluble matter is 0.001%.

The value of purity has an estimated inaccuracy of

0.1%. Emission spectrometry analysis of the ash

showed the presence of Si,

Al , Na, Ti , Fe, Mg.

Neutron activation analysis

indicated the presence of

CI , Cu , Mn

.

916

Bilirubin

Bilirubin of known purity.

The material was obtained

from the Pfanstiehl Laboratories, Inc., Waukegan,

Illinois. It was prepared

from material that was isolated from hog bile and

crystal i zed as the acid. It was purified in chloroform

solution with sodium sulfate

and recrystal ized from

chloroform.

Purity is 99.0%; chloroform

is 0.8%; insoluble in

chloroform less than 0.01%;

ash is 0.01%. The value of

the bilirubin content has a possible estimated inaccuracy of 2%. Flame emission and atomic absorption

measurements show the

presence of Li, Na , K, Ca,

Mg. Elemental composition:

C, 67.36; H, 6.24; N, 9.42;

CI , 0.73.

8
Certi fi cation Use Remarks

The purity and homogeneity

of the material was established by paper and

thin-layer chromatography,

emission spectrometry;

neutron activation, ultraviolet absorption.

For the calibration and

standardization of procedures and evaluating

working standards for uric

acid determinations in

clinical analysis. For "in

vitro" diagnostic use only.

Standard solutions made from

this material should be kept

in dark-brown bottles glassstoppered, and stored at

4 °C.

Uric acid should be stored

in well-closed containers

at 30 °C or less, and be

protected from heat and

sunlight. Under these con- ditions the material is

stable for at least 5 years.

The stock standard solutions

1 mg/mL are stable for 3

months when stored in a wel 1 -stoppered , all-glass,

dark-brown bottle at 4 °C.

The homogeneity and purity

of the material was established by paper, thinlayer, and gas-liquid

chromatography, and by

phase-solubility analysis.

The chloride was determined

by titration of a solution

obtained from an oxygen

flask combustion. Ultraviolet, infrared, and

nuclear magnetic resonance

spectra showed no evidence

of impurities.

For the calibration and

standardization of procedures and the evaluation

of working standards for

creatinine determinations

in clinical analysis. For

"in vitro" diagnostic use

only. A "stock" standard

solution is made by dissolving 0.100 g of

creatinine into 100 mL

0.1 N HC1

.

Creatinine should be stored

in well -closed container at

30 °C or less, protected

from heat and sunlight.

Refrigerated storage is

recommended. Under these

conditions the material is

stable for 5 years. The

"stock" standard solution (1

mg/mL) prepared as described

was found to be stable

indefinitely when stored at

4

C C in a wel 1 -stoppered

all-glass container.

The certification of SRM 916

is based on the best current

state-of-the-art knowledge.

In spite of decades of work

on bilirubin, it is still

felt that much of its basic

chemistry is incomplete.

For the calibration and

standardization of

procedures for bilirubin

determinations for for

evaluation of the daily

working standards. For

"in vitro" diagnostic

use only.

Bilirubin is light sensitive, thus all manipulation

should be performed under

low-intensity incandescent

light. It should be stored

under conditions that

totally exclude light. SRM

916 should be kept in the

tightly closed vial in a desiccator at 4 °C. Under

proper storage the material

is stable for at least 3

years. Solutions of bilirubin prepared as described

in the Certificate may be

preserved for about 1 week

at -20 °C.

9
Table 2. A. Organics

SRM

continued

.

Material Composition

917

D-Glucose (Dextrose)

D-Glucose of known purity.

The material was obtained

from the Pfanstiehl

Laboratories , Inc .

,

Waukegan, Illinois.

Purity is 99.9%; a-D-Glucopyranose >99.0%; e-D-Glucopyranose <1 .0%; moisture

0.06%; ash 0.002%. Insoluble matter 0.001 to 0.005%

nitrogen < 0.001%. Purity

is given with an estimated

inaccuracy of ±0.1%.

Paper, thin-layer, and

high pressure ion-exchange

chromatography revealed no organic impurities. Emission spectrometry showed

the presence of Ca, Mg, Si,

AT, B, Fe, Cu, Na . Turbidimetry showed the presence

of S, CI .

920

D-Mannitol

D-Mannitol of known purity.

The material was obtained

from the Pfanstiehl

Laboratories, Inc.,

Waukegan, Illinois.

Purity is 99.8%; D-Glucitol

is 0.1%; total Alditol is

99.9%; loss on drying is

<0.02%; ash is <0.001%;

insoluble matter is <0.001%.

The value for purity has an estimated inaccuracy of

0.1%. Melting point is

167.0-168.0 °C. Carbon

39.51% and hydrogen 7.86%.

921

Cortisol (hydrocortisone)

Cortisol of known purity.

The material was obtained

from the Upjohn Co.

,

Kalamazoo, Michigan.

Purity is 98.9%;

21-Dehydrocortisol is 0.6%;

21 -^-Acetyl Cortisol is 0.2%;

21 -Dehydrocorti sone is 0.1%;

Cortisone is 0.1%; total

steroids is 99.9%; ash is

0.002%; insoluble matter is

0.001%; loss on drying is

0.08%. The Cortisol assay

has an estimated inaccuracy

of 0.2%. Elemental analysis

showed carbon 69.49% and

hydrogen 8.39%. Melting

point is 219.0 to 220.5 °C.

10
Certi f ication Use Remarks

The proportion of

a-D-Glucose anomer was estimated by gas-liquid

chromatography, differential

scanning calorimetry, and

proton magnetic resonance

spectroscopy at 90 MHz.

For calibration and

standardization of

procedures for glucose

determinations and

evaluation of working

standards in cl inical

analysis. For "in vitro"

diagnostic use only. All

solutions of D-Glucose

should be clear and without

bacterial growth.

D-Glucose should be stored

in a well-closed container

at 30 °C or less, protected

from heat or direct sunlight. Refrigerated

storage is recommended.

Under proper storage this

material is stable for at

least 5 years

.

The purity of the material

was determined by differential scanning calorimetry;

phase solubility analysis;

thin-layer chromatography;

infrared and ultraviolet

spectrometry; and proton

and carbon-13 magnetic

resonance spectroscopy.

Optical rotation in water

is [a]2° = -0.3°.

For calibration and standardization of procedures

for determination of

triglycerides in

clinical chemistry. For

"in vitro" diagnostic

use only.

The material should be

stored in a well -closed

container at 30 °C or less,

protected from direct sun- light. Under these conditions it is stable for at

least 5 years. Stock standard solutions (1 ymol/mL)

should be stored in glass

stoppered, brown bottles at

4 °C. Under such conditions

these standards should be

stable for 6 months.

The identification and

quantitation of the 4

steroid impurities were

made by Fourier-transform

proton-magnetic resonance

spectroscopy; liquid and

thin-layer chromatography.

Homogeneity was established

by C and H analysis.

Optical rotation at x 589 nm

is 168.9°, and at x 365 nm

is 571 .7° at 20 °C.

For the calibration and

standardization of

procedures for Cortisol

determinations in clinical

analysis. For "in vitro"

diagnostic use only.

The material should be

stored in a well -closed

container at 30 °C or less,

protected from direct sunlight. Refrigerated storage

is recommended. Under these

conditions the material is

stable for 5 years. The

solution of 1 mg/mL Cortisol

in ethanol should be stored

in a well -stoppered , allglass container at 4 °C.

Under these conditions the

solutions are stable for

6 months.

11
Table 2. A. Organics - continued.

SRM Material Compos i tion

925

4-Hydroxy-3-MethoxyDL-Mandelic Acid (VMA)

VMA of known purity. The

material was prepared at

NBS.

Purity is 99.4%; uncharacterized compound 0.5%;

keto-VMA 0.1%; volatile

matter 0.02%; ash 0.004%.

The value of purity has an estimated inaccuracy of

0.4%. Melting range is

133-134 °C. Elemental

analysis: carbon 54.6;

hydrogen 5.1; oxygen 40.3.

926

Bovine Serum Albumin

(Total Protein Standard)

Bovine Serum Albumin of

known purity. It was prepared by the Research

Division, Miles Laboratories, Inc. Kankakee,

Illinois.

Mass fractions (g/g): Ash

0.0006; hexose 0.00034;

citrate + pyruvate + lactate

0.00015; lipid 0.0003; non- protein amino compound

0.00002; water 0.048;

protein impurities (dimer)

by: gel electrophoresis,

0.043; gel chromatography,

0.050.

927

Bovine Serum Albumin

(7% Solution)

(Total Protein Standard)

Solution of known protein

concentration and purity

prepared from SRM 926

described above. It was prepared by the Research

Division, Miles Laboratories

Inc., Kankakee, Illinois.

The 7% solution was prepared

from SRM 926. The aqueous

solution is brought to

proper ionic strength with

NaCl and to proper pH with

NaOH. It was sterilized by

membrane filtration.

938

Para-Nitrophenol

In preparation at time of writing. Certificate will be

included in Appendix B if available at time of publication.

B. Orga no -Metal 1 ic

929

Magnesium Gluconate

Di hydrate

(Clinical Standard

for Magnesium)

Magnesium gluconate

di hydrate of known purity.

This material was obtained

from the J. T. Baker

Chemical Co., Phillipsburg,

New Jersey

Practically pure magnesium

gluconate dihydrate.

12
Certification Use Remarks

Thin-layer chromatography

has revealed two impurities.

Phase solubility analysis

of VMA were inconclusive.

The sample contains a carboxylic acid equivalent

of 99.83%. The material

was characterized by

gas-liquid chromatography.

For cal i bration and

standardization of

procedures for VMA used

in clinical analysis.

For "in vitro" diagnostic

use only.

Solutions of VMA exposed to

light and air are unstable.

VMA should be kept in the

well-closed original bottle

and in a desiccator.

Refrigeration at 4 °C, or better, -20 °C is recom- mended. VMA should be

protected from sunlight or ultraviolet radiation. The

material should not be used

after 5 years from the date

of purchase.

SRM 926 conforms to the

specifications approved by

the National Committee for

Clinical Laboratory Standards. The analytical

techniques used in the

certification of this

material are those

recommended by the

National Committee.

For cal i brat ion of

procedures for total serum protein determinations.

For "in vitro" diagnostic

use only.

SRM 926 should be stored in

a well -closed container at

4 °C, protected from sun1 ight or ul traviol et

radiation. Under these

conditions it is stable for

3 years. The lyophilized

material is extremely

hygroscopic

.

SRM 927 conforms to the

specification for standardized protein solution

approved by the National

Committee for Clinical

Laboratory Standards.

Peptide mass (g/L) 70.45

(biuret method); 70.48

(Kjeldhal method) 70.77

(optical density method)

;

pH 6.66.

For calibration of procedures for total serum protein determinations and

for "in vitro" diagnostic

use only. SRM 927 should

not be used in dye-binding

tests, for checking refractometers, or as an immunochemical standard. Not

recommended for use in

bilirubin tests.

The solution is supplied in

sealed ampoules and must be

stored at 4 °C. Opened

ampoules should not be

stored. Sealed ampoules

stored at 4 °C are stable for

3 years. SRM 927 should not

be used after 3 years from

purchase. Once an ampoule

is opened, the solution

should be used promptly.

Certified for magnesium

content of 5.403 wt. %,

by thermal ionization

isotope dilution mass spectrometry.

For cal i bration and

standardization of clinical

procedures for the determination of magnesium. For

"in vitro" diagnostic use

only.

Magnesium gluconate should

be stored in the tightlyclosed, original bottle at room temperature. It is

hygroscopic and must be

dried before use. Under

proper storage, the material should be stable for 5 years. Solutions prepared

from SRM 929 are stable

under normal laboratory

conditions for at least 60

days.

13
Table 2. C. Inorganic

SRM Material Composition

915

Calcium Carbonate

Calcium carbonate of known

purity. The material was obtained from the J. T. Baker Chemical Co.

,

Phil 1 ipsburg , New Jersey.

Purity is 99.9+°/; water is

0.01%. Emission and atomic

absorption spectrometry,

neutron activation analysis,

and spectrophotometry were

used to determine the

following trace metals: Cu,

Fe, Mg, Mn, Si , Na, Sr, K,

Li , Ba.

918

Potassium Chloride

(Clinical Standard)

Potassium chloride of known

purity. The material was obtained from the J. T. Baker Chemical Co.

,

Phi 11 ipsburg, New Jersey.

Purity is 99.9%. Moisture

is 0.07%. Emission

spectrometry and atomic

absorption showed the

presence of traces of Al

,

Cu, Fe, Mg, Rb, Na, Li

,

Cs, Ca.

919

Sodium Chloride

(Clinical Standard)

Sodium chloride of known

purity. The material was obtained from J. T. Baker

Chemical Co., Phil 1 ipsburg

,

New Jersey.

Purity is 99.9%. Moisture

is about 0.08%. Emission

spectrometry and atomic

absorption showed the

presence of traces of Ca,

Cu, Fe, Mg, K, Cs, Rb, Li.

924

Lithium Carbonate

Lithium carbonate of known

purity. The material was obtained from J. T. Baker

Chemical Co., Phi 11 ipsburg,

New Jersey.

Purity is 100.0 5 %; based on coulometric acidimetry. The

molecular weight is 73.9486

based on the mass-spectrometrically determined value

of 6.9696 for the atomic

weight of lithium. Emission

spectroscopy test for trace

metals was negative. Flame

emission and atomic absorption showed that alkali

metals are below 1 ppm and

calcium is 4 ppm.

14
Certification Use Remarks

Material meets or exceeds

the minimum requirements

specified for reagent grade

calcium carbonate as qiven

in Reagent Chemical

s

published by the American

Chemical Society. The

compound is stable up to

625 °C, above which

decomposition occurs as indicated by thermal

gravimetric analysis.

For the calibration and

standardization of procedures for calicium determintions in clinical analysis.

For "in vitro" only

diagnostic use. SRM 915

may be used to prepare Ca

standard solution for flame

emission, atomic absorption,

or titrimetric methods of

analysis. (See, NBS Special

Publication 260-36.)

Calcium Carbonate should be

stored in the tightly-closed

original bottle at room temperature. Under proper

storage this material was found to be stable for at

least 10 years. It is

recommended that the

material not be used after

5 years from the date of

purchase. Solutions

prepared from SRM 915 are stable indefinitely when

stored in al ass-stoppered

bottles. All solutions

should be clear.

The material meets or exceeds the specifications

for reagent grade potassium

chloride as given in Reagent

Chemicals published by the

American Chemical Society.

Potassium Chloride is

homogeneous and was assayed

at 99.98%.

For use as a standard for

potassium and, to a lesser

degree, for chloride determinations in clinical

chemistry. (See, NBS Special

Publications 260-63 and

260-67.) For "in vitro"

diagnostic use only.

Potassium Chloride should be

stored in the well -closed

original container under

normal laboratory conditions. The weighino and

other manipulations should

not be made when the relative humidity exceeds 75%.

The solutions of SRM 918 are stable indefinitely

when stored in a well -stoppered, all-glass container.

The material meet* or exceeds the specifications

for reagent grade sodium

chloride as given in

Reagent Chemical

s

publ ished

by the American Chemical

Society. Coulometric

determination of CI indicate

a purity of 99.995%.

For use as a standard for

the determination of sodium

and chlorine ions in

clinical chemistry. (See

NBS Special Publications

260-60 and 260-67. ) For

"in vitro" diagnostic use

only.

Sodium chloride should be

stored in the well -closed

original bottle under normal

laboratory conditions. The

weighing and other manipulations should not be made

where the relative humidity

exceeds 60%. Solutions of

SRM 919 are stable indefinitely when stored in a well -stoppered, all-glass

container.

No actual lithium determination was made. The

certification is based on the analysis of the carbonate anion and the proven

absence of metallic cations

above trace levels. The

material meets or exceeds

the specifications for

reagent grade lithium carbonate as given in Reagent

Chemicals published by the

American Chemical Society.

For calibration and

standardization of procedures for the determination

of lithium in clinical

chemistry. For "in vitro"

diagnostic use only.

SRM 924 should be kept in

the well -closed original

bottle under normal laboratory conditions. Solutions

of this material are stable

indefinitely when stored in

a wel 1 -stoppered , all -glass

container. The solutions

should be clear.

15
Table 2. C. Inorganic - continued.

SRM Material Composition

928

Lead Nitrate

(Clinical Standard)

Lead nitrate of known

purity. The material was obtained from J. T. Baker

Chemical Co., Phillipsburg,

New Jersey.

Assay is 100.00%. Molecular

weight is 331.219 based on

a mass-spectrometric determination of 207.209 for the

atomic weight of lead in

the sample. Emission

spectroscopy showed the

presence of Ag, Cr, Ni

.

937 Electrolytic iron metal of Assay is 99.90 wt. %.

Iron Metal known purity. The material Impurities are: Ni, Si, C,

(Clinical Standard) was taken from a selected Cr, Co, Cu, Mn, 0, S, Mo,

lot of high- purity iron P, Ge, N. Other elements

available at NBS. are <0.003%.

D. Ion-Activity

922 Compounds of known purity. Purity is 99.99 and 99.69

Tris(Hydroxymethyl )- The materials were obtained mole percent, respectively.

Aminomethane from Sigma Chemical Co.,

St. Louis Missouri

.

and

923

Tris(Hydroxymethyl )-

Ami nomethane

Hydrochl oride

2203 Potassium fluoride of After drying, the KF assays

Potassium Fluoride reagent-grade purity. at 99.5%. It is not to be

considered entirely free

of traces of chloride,

fl uorosil icates , and heavy

metal s

.

16
Certification Use Remarks

The material meets or exceeds the specifications

for reaqent grade lead

nitrate as given in Reagent

Chemical

s

, published by the

American Chemical Society.

For calibration and standardization of procedures

for lead determination in

clinical chemistry. For

"in vitro" diagnostic use

only.

This material should be

stored in the tightly-closed

original bottle under normal

laboratory conditions. The

material will not absorb

appreciable water when

exposed to 90% relative

humidity atmosphere for

5 days.

The assay was performed by

dissolution in hydrochloric

acid and by reduction with

stannous chloride and

oxidation of the excess

with mercuric chloride.

For calibration and standardization of procedures

for iron determination in

clinical chemistry. For

"in vitro" diagnostic use

only.

SRM 937 should be stored in

the tightly-closed bottle

under normal laboratory

conditions

.

The purity of the materials

was established by

coulometry. The solution

used for calibration of

oH equipment is 0.01667

molal (SRM 922) and

0.0500 molal (SRM 923).

The pH(S) of the solution

at 20 °C is 7.840.

For secondary standard pH

buffer solutions in clinical

chemistry, and in cases where phosphate buffers

would cause undesirable

side reactions. The buffer

solution is sensitive to

carbon dioxide. For "in

vitro" diagnostic use only.

SRM 922 should be stored in

a well -closed container at room temperature and protected from sunlight. Under

these conditions the material is stable for 12 years.

SRM 923 should be stored in

similar conditions. It is

stable for at least 5 years.

SRM 923 is hygroscopic and

should not be manipulated in

relative humidity exceeding

50%. Neither SRM 922 nor

SRM 923 should be used

after 5 years from date of

purchase.

Solutions of the KF are certified for the activity

coefficient of the fluoride

ion and the related pF value

at 25 °C over the molality

range of 0.0001 to 2.0.

For the standardization of

fluoride ion-selective

electrodes.

SRM 2203 is hydroscopic and

must be dried in two stages

before use: 2 hours at

110 °C followed by 2 hours

at 200±10 °C.

17
Table 2. E. Temperature

SRM Material Composition

933

Clinical Laboratory

Thermometers

Set of three thermometers.

The thermometers were manufactured by Princo

Instruments, Inc.,

Southampton, Pennsylvania.

This SRM consists of three

individually calibrated

thermometers. Each unit is

a solid-stem, mercury-inglass instrument 180 mm in

length marked with a 95 mm

immersion line. Each is

nitrogen filled above the

mercury. The main scales

of the thermometers are 24.00 to 26.00 °C; 29.00 to

31 .00 °C; and 36.00 to

38.00 °C respectively with

0.05 °C divisions.

934

Clinical Laboratory

Thermometer

One thermometer manufactured

by Princo Instruments, Inc.,

Southampton, Pennsylvania..

The thermometer is a solidstem, mercury-in-glass

instrument 300±5 mm long,

and marked with a 95-mm

immersion line. Nitrogen

fills the space above the

mercury. The main scale

extends from 24.00 to 38.00

°C in 0.05 °C divisions.

1968

Gallium Melting-Point

Standard

Gallium metal of high-purity

obtained from Eagle- Pi cher

Industries, Inc., Quapaw,

Oklahoma

.

The nominal purity of the

material is 99.99999%.

SRM 1968 is contained in

a specially designed

epoxy-sealed cell made at

NBS from a Teflon body, a nylon well , and a nylon

cap stem.

F. Spectrophotometry and Fluorescence

1. Solids

930 Solid filters made of Three filters with nominal

Glass Filters for Schott NG 4 and NG 5 transmittances of 10, 20,

Spectrophotometry optically neutral glass. 30%. Each filter is mounted

Obtained from the Schott- in a black anodized aluminum

Jenaer Glaswerk, Mainz, holder provided with front

Germany, and rear shutters. The

filters are stored in a cylindrical aluminum

contai ner.

18
Certification Use Remarks

Calibrated points are 0 °C

and 25, 30, or 37 °C

depending on the scale of

the individual thermometer.

(See NBS Special Publication

260-48.)

SRM 933 is intended for use

in clinical laboratories

as a primary cali brant in

clinical enzymology.

Each thermometer has an auxiliary scale from -0.20

to +0.20 °C with 0.05 °C

divisions.

Calibrated points are 0,

25, 30, and 37 °C. (See

NBS Special Publication

260-48.

)

SRM 934 is intended for use

in clinical laboratories

as a primary cali brant in

clinical enzymology.

The thermometer has an auxiliary scale from -0.20

to +0.20 °C with 0.05 °C

divisions

.

The certified melting point

is 29.7723 °C. It was established using a set of

3 stable thermistors that were calibrated against a standard Platinum Resistance

Thermometer. The uncer- tainty represents one-half

of the total range of the

temperatures observed in

152 determinations of the

melting points of this and

similar samples of SRM 1968.

SRM 1968 is intended to be

used to calibrate thermometers near 30 °C. It should

be used in a temperatureregulated bath.

SRM 1968 can be used to

calibrate all thermometers

that have temperature

sensing elements smaller

than 3.5 mm in diameter.

The gallium cell should not

be immersed in water for more than 2 days. Water

should not enter the cell.

(See MBS Special Publication

481, Gallium Meltinq-point

Standard (1977).)

The transmittance of each

filter is measured with the

high-accuracy spectrophotometer at X 440, 465, 546.1

,

590, 635 nm, using spectral

bandpasses of 2.2, 2.7, 6.5,

5.4, 6.0 nm respectively.

This SRM is intended as a reference source for the

verification of the transmittance and absorbance

scales of conventional

spectrophotometers

.

The use of this SRM is

limited to the visible spectrum and requires narrow

spectral bandpasses. For

further details consult the

Certificate included in the

Appendix; see also NBS

Soecial Publication 260-51.

19
Table 2. F. Spectrophotometry and Fluorescence - continued.

SRM Material Composition

2030 Solid filters made of One glass filter with a Glass Filter for Schott NG 4 and NG 5 nominal transmittance of

Transmittance optically neutral glass. 30% in a black anodized

Measurements Obtained from the Schott- aluminum holder with shutJenaer Glaswerk, Mainz, ters. The filter is stored

Germany, in a wood-like plastic box.

2031

Metal -on-Quartz

Filters for

Spectrophotometry

Solid filters made of semitransparent evaporated

chromium-on-fused silica

(non-fluorescent) plates.

Sets 1 through 95 prepared

by Cosmo Optics , Inc .

,

Middletown, New York;

subsequent sets prepared

by NBS Optical Shop.

Three filters with nominal

transmittances of 10, 30,

90%. Each filter is made

from two fused silica plates

assembled by optical contact. The 90% filter is

made by assembling 2 clear

plates. The 10% and 30%

filters are made by assembling a fused silica plate

which carries a film of

semi transparent chromium to

produce the desired transmittance, and a clear

plate. Each filter

assembly is placed in a metal holder provided with

shutters

.

2. Liquids and Cuvettes

931b

Liquid Absorbance

Standards for Ultraviolet

and Visible

Spectrophotometry

Liquid filters made from a solution of Co and Ni metals

dissolved in a mixture of

nitric-perchloric acids.

The pH of the solution is

about 1. Prepared in the

NBS Center for Analytical

Chemistry.

Three solutions and a blank

are delivered in sealed

ampoules and have nominal

absorbances of 0.1 to 0.9.

935

Crystalline Potassium

Dichromate for Use as an Ultraviolet Absorbance

Standard

Crystalline potassium

dichromate of established

purity obtained from the

J. T. Baker Chemical Co.,

Phi 1 1 i psburg , New Jersey.

The crystalline material of

reagent grade purity is

offered in glass bottles

provided with plastic screw

caps

.

20
Certification Use Remarks

The transmittance of the

filter is certified as for

SRM 930 but only for A 465

nm and for a nominal

transmittance of 30%.

This SRM is intended as a reference source for onepoint verification of the

transmittance or absorbance scales of

spectrophotometers

.

Same as for SRM 930. SRM

2030 is particularly useful

in connection with the

chemical analysis of spices.

A copy of the Certificate is

included in the Appendix.

The transmittance of each

filter is measured with the

high-accuracy spectrophometer at X 250, 280, 340,

360, 400, 465, 500, 546.1,

590, 635 nm.

This SRM is intended as a reference source for the

verification of the transmittance and absorbance

scales of conventional

spectrophotometers in the

ultraviolet and visible

spectral region.

SRM 2031 has a good optical

neutrality and can be used

to verify spectrophotometers

with wide spectral bandpasses from about 200 to

800 nm (with possible

extension to X 3 urn). For

further details consult the

Certificate in the Appendix;

see, also NBS Special

Publication 260-68.

The absorbance of each solution was measured at A 302,

395, 512, 678 nm using

spectral bandpasses of 1.0,

1 .7, 2.0, 6.5 nm respectively. The certification

is made with an uncertainty

of about ±1 .0%.

This SRM was primarily

intended for the verification of the accuracy of

transmittance or absorbance

scales of spectrophotometers.

Requires the use of SRM 932

and of narrow spectral

bandpasses. Provides only one certified value in the

ultraviolet. For further

details consult the Certificate included in the

Appendix

.

The apparent specific

absorbance is certified for

five concentrations at A 235,

257, 313, 345, 350 nm using

spectral bandpasses of 1.2,

0.8, 0.8, 0.8, 0.8 nm respectively, using SRM 932.

This SRM is intended to be

used as a reference standard

for the verification of the

accuracy and linearity of

the absorbance scale of

spectrophotometers

.

Requires accurate preparation of solutions of

potassium dichromate in

0.001N perchloric acid.

Requires the use of SRM 932

and of narrow spectral bandpasses. Can be used only in

the ultraviolet. For

further details consult the

Certificate included in the

Appendix; see also NBS

Special Publication 260-54.

21
Table 2. F. Spectrophotometry and Fluorescence - continued,

SRM Material Composition

932

Quartz Cuvette for

Spectrophotometry

All -quartz cuvette made of

non-fluorescent fused silica

of optical quality. The

first 100 cuvettes were prepared by the NBS Optical

Shop; subsequent units were

prepared to NBS specifications by Starna, Ltd.

,

Dayenham, England.

Each cuvette is made

entirely of fused silica and

is provided with a Teflon

stopcock. The transparent

windows are attached to the

body of the cuvette by

direct fusion. The cuvettes

are stress-relieved by

proper annealing. The

cuvette is stored in a transparent plastic

container.

3. Stray Light

2032

Potassium Iodide for use

as a Stray Light Standard

Crystalline potassium

iodide of established

purity, obtained from the

J. T. Baker Chemical Co.,

Phil 1 ipsburg, New Jersey.

The reagent-grade, crystalline KI is 99.8% pure as indicated by the manufacturer. Moisture is 0.007%.

Homogeneity was tested by

absorbance measurements at

265, 267, and 270 nm, and was found adequate.

2033

Potassium Iodide for use

as a Stray Light Standard

with Radiation Attenuator

Crystalline potassium iodide

of established purity, and

two semi-transparent evaporated metal -on-fused silica

filters contained in a metal

holder provided with shutters. The KI was obtained

from the J. T. Baker Chemical Co. , Phil 1 ipsburg,

New Jersey. The filters and

the holder were made by the

MBS Instrument Shop.

Potassium iodide as for

SRM 2032. Two semitransparent evaporated

chromium-on-fused silica

(non-fluorescent) filters

of optical quality.

4. Wavelength

. 2009

Didymium Glass Filter for

Checking the Wavelength

Scale of Spectrophotometers

The didymium glass was prepared by Corning Glass

Works, Corning, New York,

as Corning 5120 Filter

Glass.

Rare earth oxides in a glass

matrix. This filter is 1 cm wide, 3 cm high, and 3 mm

thick. Each filter is

placed in a metal holder

which fits into the cuvette

holder of the spectrophotometer.

2010

Didymium Glass Filter for

Checking the Wavelength

Scale of Spectrophotometers

Same as SRM 2009. Rare earth oxide in a glass

matrix. This filter is

5.1 cm square and 3 mm

thick.

22
Certification Use Remarks

The nominal inner pathlength

is 10 mm and it is certified

at 10 points along the

height of the transparent

windows with an uncertainty

of ±0.0005 mm. The cuvettes

are 12.5 mm square and 48 mm

high.

To be used when accurate

transmittance or absorbance

measurements are made on liquid samples. Should be

used in conjunction with

SRM's 931, 935, 2032, and

2033.

For further details consult

the Certificate included in

the Appendix; see also NBS

Special Publication 260-32.

The specific absorbances

were measured with the highaccuracy sDectrophotometer

at 240, 245, 250, 255, 265,

270, and 275 nm and 23.5 °C

using a spectral bandpass of

0.2 nm. The measurements were performed using SRM 932

quartz cuvettes.

SRM 2032 is intended to be

used to assess heterochromatic stray light in the

ultraviolet region below

260 nm, in absorption

spectrophotometers. It is

recommended that SRM 932

be used in the measurements.

SRM 2032 should be stored

in the original, low-actinic

glass bottle and cardboard

container, protected from

exposure to light and

humidity. The estimated

stabil ity is 3 years

.

Same as for SRM 2032. The

transmittance of the

evaporated metal -on-fused

silica filters was measured

at 255 nm with the highaccuracy spectrophotometer.

The nominal value is 10% for

each filter, and a combined

value of 1%.

SRM 2033 is intended to be

used to assess heterochromatic and isochromatic

stray light in absorption

spectrophotometers

.

Same as for SRM 2032. The

two semi-transparent

evaporated metal -on-fused

silica filters in the metal

holder should be stored in

the plastic container

provided with SRM 2033.

The wavelengths of maximum

absorption was determined

with a high-Drecision

spectrophotometer for bandwidths in the range 1.5 to

10.5 nm and for 14 to 24

wavelengths in the range 400

to 760 nm. The instrument

has a wavelength accuracy

of 0.04 nm.

The filters are intended to

be used in calibrating the

wavelength scale in the

visible spectral region for

spectrophotometers having

nominal bandwidths in the

range 1.5 to 10.5 nm.

SRM 2009 was not measured

individually. It is

recommended for most

applications. For further

details consult NBS Special

Publication 260-66.

Same as SRM 2009. Same as SRM 2009. Same as SRM 2009.

23
Table 2. F. Spectrophotometry and Fluorescence - continued.

SRM Material Composition

2013 Same as SRM 2009. Same as SRM 2009.

Didymium Glass Filter for

Checking the Wavelength

Scale of Spectrophotometers

2014 Same as SRM 2009. Same as SRM 2009.

Didymium Glass Filter for

Checking the Wavelength

Scale of Spectrophotometers

2034

Holmium Oxide for use as Wavelength Standard in

Spectrophotometry and

Fluorescence Spectrometry.

(Planned SRM)

Holmium oxide of

established purity

dissolved in perchloric

acid.

Holmium oxide is to be

offered in solutions in

sealed 10 mm quartz

cuvettes

.

5. Fluorescence

936

Quinine Sulfate

Di hydrate

The quinine sulfate dihydrate was a special lot of

material obtained from

J. T. Baker Chemical Co.

,

Phillipsburg, New Jersey.

SRM 936 contains 1 .7%

impurities determined by

liquid chromatography and

believed to be di hydroquinine sulfate dihydrate.

The water content is

4.74±0.05% by the

Karl Fisher method and

4.57±0.04% weight loss.

Theoretical value is 4.60%,

?A
Certification Use Remarks

Every filter was measured

individually , hence the data

provide a more accurate

representation of the

optical properties of 'the

individual filter.

Same as SRM 2009. SRM 2013 was measured

individually and should be

used when assurance in the

evaluation of an instrument's wavelength scale is

hi ghly critical . For

further details consult NBS

Special Publication 260-66.

Same as SRM 2013. Same as SRM 2009. Same as SRM 2013.

The wavelengths of maximum

absorption of holmium oxide

solutions in perchloric

acid will be determined for

various spectral bandpasses

at the nominal wavelengths;

279, 288, 338, 361, 386,

418, 453, 536, 637 nm.

This SRM is intended to be

used as a reference standard

for the verification of the

accuracy of the wavelength

scale of absorption and

fluorescence spectrometers,

in the ultraviolet and

visible spectral regions.

Holmium oxide solutions in

perchloric acid were selected as a wavelength standard

because the absorption bands are narrower than those of

the holmium oxide glass.

The use of solutions in con- junction with a diffusing

screen (Teflon) placed at

45° in the 10 mm cuvette

permits the use of SRM 2034

for the wavelength calibration of fluorescence

spectrometers. The issuance

of SRM 2034 is projected for

the end of 1981

.

The material is certified

for the relative molecular

emission spectrum E(x), in

radiometric units for a solution of 1.28 x 10" 6 mol/L in 0.105 mol/L

perchloric acid, using an excitation wavelength of

347.5 nm. The certified

values of the molecular

emission spectrum at 5 nm intervals from 375 to 675 nm are given. This

certification was made

with the NBS reference

fluorescence spectrometer.

For evaluation of methods

and the calibration of

fluorescence spectrometers.

A solution of 0.1 mg/mL in

1000 mL 0.105 mol/L perchloric acid is recommended.

It should be stored in the

dark in a wel 1 -stoppered

glass bottle. This solution

is stable for three months.

SRM 936 is for "in vitro"

diagnostic use only.

The material should be kept

in its original bottle and

stored in the dark at 30 °C or less. Under these

conditions SRM 936 is

stable for three years.

(See NBS Special Publication 260-64.)

25
Table 3. NBS Publications in the "260 Series" Related to Clinical Chemistry.

Publ 1 UL/ 1 i1 ration V<U t lull Short Title SRM •J l\l 1 No11 u •

260-32 yUQI L L. L-UvCLLCO IUI JUCLII UpilUlUIMCUl V 932

PvO3 11 pL i1 iUN!im inIll ^py*i JC 1 UNIim pfMp+hnH^ ^ 1IC LI IUU ^

260-48 CI inical ThprmomPtprs 933 934

pcf)_c-| lUU %J 1 ni^cc Flippy* "frw ^nert rnnhntnmot y*\/

\Ji\ 1 lea b U 1 ferine II Lb J c. L > Zf c.o \ d 1 IU 1 J U LI Ic i b y

r ULCIod 1 Ulll U I Lilt UNIalt U V J IdllUdl u

260-60 ^nH juu vii uiii im iniii jc^p ymi uiii im fMpthnH^ ^"ic u iuu y J 1 .7

?60-63 ilUU U J PnT^Qciiim r u lqjo i uiii iniii ^po l vii uiii im fMpthnrO ^ric tnuu ^ 1 o

260-64 fhiininp yu i ii i lie ^iilfatp ju i i a lc Fli i nnrp^rpnrp uui c jlciilc ^tanrtarH j uaiiucu u 936

260-66 un ti Hvm \jy in 1i 1uiii im Ru 1i aj <;o Wfl nave\/plpnn1"h i cnu in ^tanH^ioflc JLaiiuai uo 2009 2010 2013 2014

UlllUi lUC III O tr 1 UIII ^ lit! LI iuu y J IO, J 1 J

260-6ft t. UU UU Mp1* 1 IL La^11 — nn- Ull Oi-ia yUalv*tLi.7 1Fi1 11 tprc LCI S

260-69 1L ithinm 1 LI 1 1 UIII inIII JC^prnm 1 UIII fMpthnrO ^ 1 IC LI iuu y 924

260-xx Potassium Iodide Stray Light Standard 2032, 2033

260-72 Antiepilepsy Drug Level Assay Standard 900

While all of the publications listed in Table 3 should prove valuable to users of

SRM's, two provide additional information that should benefit a much wider audience. In

SP 260-51, Appendix III is a partial reprint of NBS Letter Circular 1017, Standard for

Checking the Calibration of Spectrophotometers, which was first issued in 1955 and

reissued in 1967, but has been out of print for several years. In SP 260-54,

Appendix III is SP 260-32, Standard Quartz Cuvettes for High Accuracy Spectrophotometry;

Appendix V is NBS Circular 602, Testing of Glass Volumetric Apparatus (1959); and

Appendix VI is NBSIR 74-461, The Calibration of Small Volumetric Laboratory Glassware

(1974).

Other NBS publications, not in the "260 Series," and a number of NBS staff authored

papers have been published that deal with specific SRM's or measurement techniques used in

clinical chemistry. Some of these are: SP 481, Gallium Melting Point Standard, which

describes SRM 1968; SP 148, The Role of Standard Reference Materials in Measurement

Systems, which describes the SRM program in general, and briefly the use of SRM's in

clinical measurements; and both SP 378, Accuracy in Spectrophotometry and Luminescence

Measurements, and SP 466, Standardization in Spectrophotometry and Luminescence Measurements, contain papers of particular interest to clinical chemists. Another publication

that should be of interest is SP 492, Procedures Used at the National Bureau of Standards

to Determine Selected Trace Elements in Biological and Botanical Materials.

26
Appendix I. Alphabetical Index of SRM's

ACIDIMETRIC

Benzoic acid Potassium phthalate. acid ALLOYS CHEMICAL COMPOSITION

(See also individual metals) Aluminum

Chip form

Wire (neutron monitor density). Cobalt Chip form

Wire (neutron monitor density) Copper

Chip form

Microprobe

Solid form

Ferro (steelmaking) Gold

High-purity

Microprobe wire High temperature

Solid form

IronChip and granular form

Microprobe

Solid form

LeadChip form

Solid form Magnesium

Chip form Molybdenum

Microprobe

Nickel Chip form

Oxides

Solid form

Platinum Doped, wire

High-purity, wire Selenium

Granular form

SilverMicroprobe

Solder Chip form

Solid form

TinChip form

Titanium Chip form

Solid form

Gas-in Tungsten

Microprobe

Spelter ZincChip form

High-purity

Solid form Zirconium Chip form

Solid form ALUMINUM

Al-Co alios (neutron density monitor wire) Al-Si alloy Freezing point standard

Metallo-organic compound

Radioactivity

Wrought alloy

AMERICIUM

Radioactivity

AMMONIUM D1HYDROGEN

PHOSPHATE

Fertilizer ANALYZED GASES (ENVIRONMENTAL)

Carbon dioxide in nitrogen

Carbon monoxide in air Carbon monoxide in nitrogen Methane in air Methane-propane in air Nitric oxide in nitrogen

Oxygen in nitrogen

Propane in air Sulfur dioxide in nitrozen ANALYZED LIQUIDS AND SOLIDS

(ENVIRONMENTAL)

Coal, sulfur in Coal, trace elements in Coal fly ash, trace elements in Fuel oil, trace elements in Mercury in coai Mercury in water

Nickel and vanadium in residual oil Permeation tubes

Sulfur in distillate fuel oil Sulfur in residual fuel oil Trace elements in water ARSENIC

Trioxide (oxidimetric value) ASSAY STANDARDS

(See specific constituent) BARIUM

Metallo-organic compound

BASIM ETRIC

Tris(hydroxvmethl)aminomethane

BENZENE ON CHARCOAL

BENZOIC ACID

Acidimetric Calorimetric Microchemical BERYLLIUM ON FILTER MEDIA

BIOLOGICAL STANDARDS

Brewers yeast

Liver, bovine Orchard leaves Oyster tissue Pine needles Rice flour Spinach Tomato leaves Tuna, Albacore Wheat fiour BISMUTH

Radioactivity

BORON

Boric acid Boric acid (B-IO enriched) Metallo-organic compound

CADMIUM

Metallo-organic compound

Radioactivity

Vapor pressure CALCIUM

Carbonate (clinical) Chloride (ion selectivity) Metallo-organic compound

Moiybdate (steelmaking)

V
CALOR1METRIC

Combustion calorimetric Heal source CANE SUGAR (Sucrose) CARBIDES

Tungsten carbide CARBON

Channel black (rubber compounding)

Conducting black (rubber compounding) Gas furnace black (rubber compounding)

Oil furnace black (rubber compounding)

Carbon dioxide in nitrogen

Carbon monoxide in nitrogen

CARBON STEELS

CARBON TETRACHLORIDE ON

CHARCOAL

CAST IRONS

Blast furnace Car wheel Chip form

Ductile Nodular

Solid form White CAST STEEL

CELLULAR PLASTICS

CEMENTS

Portland (chemical composition)

Turbidimetric and fineness CERAMIC MATERIALS

Carbides

Glasses Minerals

Refractories CERIUM

Radioactivity

CESIUM

Radioactivity

CHEMICAL STANDARDS

Primary

Acid potassium phthalate. Arsenic trioxide Benzoic acid Boric acid Potassium chloride Potassium dichromate Sodium oxalate Sucrose Tris(hydroxymethyl)aminomethane

Uranium oxide

Intermediate purity Selenium

Zinc CHLORINE

Isotopic rclerence

Radioactivity' CHLOROFORM ON CHARCOAL

CHROMIUM

' Ferro (steelmaking)

Metallo-organic compound

Isotopic rclerence Radioactivity

Refractories CLAYS

Flint

Plastic CLINICAL LABORATORY STANDARDS

Antiepilepsy drug level assay

Bilirubin Bovine serum albumin (powder)

Bovine serum albumin (solution) Calcium carbonate

Cholesterol

Creatinine

Cortisol Gallium melting point Glass filters for spectropnoiomelry

I'-Glucose Iron metal Lead nitrate Liquid filters for spectrophotometry Lithium carbonate Magnesium gluconate

oMannitol

Metals on quart/ filters Potassium chloride Potassium dichromate Quartz cuvette for spectrophotometry

Quinine sulfate dihydra;e

Sodium chloride Thermometers, enzymology

Tris(hydroxymeth> l)aminomethane

Tris(hydroxymethyl)aminornethane HCI

Urea

Uric acid VMA

COAL

Fly ash, trace elements in Mercury in Sulfur in Trace elements in COATING THICKNESS

Copper on steel Gold on copper Gold on copper-clad glass-epoxy laminate Gold on Fe-Ni-Co glass sealing alloy Gold on nickel Nickel on brass Nickel on steel Tin on steel COBALT

Metallo-organic compound

Radioactivity

See, Alloys

COLOR STANDARDS

COPPER

"Benchmarks'* (chips) "Benchmarks" (solids) Beryllium copper alloys BrassAluminum

Cartridge Free cutting Naval Red

Sheet Bronze Commercial

Leaded tin Silicon Coating thickness Concentrate

Cupro-nickel (chips) Cupro-nickel (solids) Freezing point

Gilding metal

isotopic reference Linear thermal expansion

Metallo-organic compound

Microprobc (gold-copper wnes)

Mill heads

Mill tails Nickel silver alloy

28
DENSITY STANDARDS

Neutron density wire Photographic

Smoke density, flaming

Smoke density, non-flaming

2.2.4-trimeth\lpentane X-rav DEXTROSE (Glucose) 1,2-DICH LOROETH ANE ON CHARCOAL

DIELECTRIC

Cyclohexane

l,2-dich!oroethane Nitrobenzene DIFFERENTIAL THERMAL ANALYSIS

p-DIOXANE ON CHARCOAL

ENVIRONMENTAL STANDARDS

Gases

Liquids

Radioactivity

Solids ELASTICITY

ELECTRICAL RESISTIVITY

EMITTANCE

FELDSPARS

Soda

Potash FERRO- (STEELMAK.ING ALLOYS)

Chromium

Niobium

Phosphorus

Silicon FERTILIZER

Ammonium dihydrogen phosphate

Phosphate rock Potassium dihydrogen phosphate

Potassium nitrate FILTERS

Glass for spectrophotometry

Liquid for spectrophotometry

FISSION TRACK. GLASSES

FLAMMABILITY STANDARDS

Flame spread index (hardboard sheet) Smoke density, flaming

Smoke density, non-flaming

See also, Special Reference Materials FLUORINE IN L'RINE

FLUORSPAR

Assay

Geological

FORENSIC STANDARDS

Glass, refractive index

Silicone liquids, refractive index FREEZE DRIED URINE

Fluorine Mercury

FREEZING POINT STANDARDS

Defining fixed points Tin

Zinc Determined reference points

Aluminum

Copper

Lead Mercury

Tin

Zinc FUELS (see. environmental)

(sooctane n-Heptane

GALLIUM

Melting point

GAS TRANSMISSION

Polyester plastic film lor oxvgen GASES, ANALYZED

Carbon dioxide in nitrogen

Carbon monoxide in air Carbon monoxide in nitrogen Methane in air Methane-propane in air Nitric oxide in nitrogen

Nitrogen dioxide permeation device Oxygen in nitrogen

Propane in air Sulfur dioxide in nitrogen Sulfur dioxide permeation tubes GASES IN METALS

"GASOLINE"

Lead in Fuel ratings GEOLOGICAL

Fluorspar

GLASS

Chemicai composition

Filters for spectrophotometry

Fission track Physical properties Refractive index Spheres for sie\e calibration (sizing standards)

Stress-optical coefficient Trace elements in GLUCOSE (Dextrose)

Clinical Primary chemical GOLD

Coating thickness on epoxy on Fe-Ni-Co glass sealing alloy on nickel High-purity

Microprobe

Vapor pressure HEAT STANDARDS

Calorimetric Freezing points

Melting points

Superconductive fixed points Thermal conductivity Thermal expansion

Thermocouple materials Vapor pressure HEAT SOURCE

Zirconium-banumchromate

HIGH-PURITY METALS

Gold, wire and rod Platinum, wire Zinc HIGH TEMPERATURE ALLOYS

HYDROCARBON BLENDS

HYDROGEN

in steel (GM-I. GM-2)

in titanium

Radioactivity

INDUSTRIAL HYGIENE

Benzene

Beryllium, filter Carbon tetrachloride Chloroform

1 ,2-Dichloroethane

p-Dioxane

Fluorine in urine Mercury in urine Metals filter

29
Quart/, filler Trichloroelhylene

m-Xylene

ION-ACTIVITY

Ion-selective electrodes pD standards pH standards IRON

Chip form

Electrical resistivity Metallo-organic compound

Ores

Radioactivity

Solid form Thermal conductivity

IODINE

Radioactivity

ISOTOPIC REFERENCE STANDARDS

Boron, natural Boron, enriched Bromine

Chlorine Chromium

Copper

Lead, equal atom (206/208) Lead, natural Lead, radiogenic, 92% lead-206 Lead-206, spike

Magnesium

Rhenium

Rubidium

Silicon

Silver Strontium Uranium-235. spike

KRYPTON

Radioactivity

LEAD

Alloys

Bearing metal

Freezing point Gasoline

Isotopic reference Metallo-organic compound

Nitrate, clinical Solder LIGHT SENSITIVE STANDARDS

Faded paper strips Light sensitive papers

Light sensitive plastic chips

LIMESTONE

Argillaceous Dolomitic LINERBOARD FOR TAPE ADHESION

TESTING

LIQUIDS, ANALYZED

Lead in gasoline Nickel and vanadium in residual oi! Sulfur in residual fuel oil Sulfur in distillate fuel oil LITHIUM

Metallo-organic compound

Ores LOW ALLOY STEELS

Chip form

Solid form MAGNESIUM

Alloy

Gluconate, clinical Isotopic reference Metallo-organic compound

MAGNETIC

Susceptibility Tape, computer amplitude reference MAGNIFICATION STANDARD

MAGANESE

Fluoride, magnetic susceptibility Metallo-organic compound

Ore MARAGING STEEL

MERCURY

Freezing point

Metallo-organic compound

Radioactivity Trace element in coal Trace element in urine Trace element in water MELTING POINTS

Alumina

Gallium METALLO-ORGANIC COMPOUNDS

Aluminum

Barium Boron Cadmium

Calcium

Chromium

Cobalt Copper

Iron Lead

Lithium Magnesium

Manganese

Mercury

Nickel Phosphorus

Potassium

Silicon

Stiver Sodium

Strontium Tin Vanadium

Zinc METALLURGICAL STANDARDS

Austenite in ferrite Iron carbide in ferrite METALS

Alloys-see index entry Elements-see index entry Freezing points Gas-in

High-purity

Melting points

Microprobe

Resistivity, electrical Thermal conductivity

Vapor pressure METALS ON FILTER MEDIA

Beryllium

Cadmium

Lead Manganese

Zinc MICROCHEMICAL STANDARDS

Acetanilide Anisic acid Benzoic acid o-Bromobenzoic acid m-Chlorobenzoic acid Cystine

30
p-Fluorobenzoic acid Nicotinic acid Triphenyl phosphate

Phosphate

Urea MICROCOPY RESOLUTION TEST

CHARTS

MICROPROBE STANDARDS

Cartridge brass Classes for microanalysis

Gold-copper

Gold-silver lron-3% silicon Tungsten-20r

c molvbdenum

MINERALS

Clays

Flint Plastic Feldspar Potash Soda

Limestone

Agrillaceous Dotomitic Ores

Bauxite Copper

Fluorspar

Iron Lithium Molybdenum

Phosphate rock Tungsten

Zinc MOLECULAR WEIGHT

Polyethylene

Polystyrene

MOLYBDENUM

Concentrate (ore) Heat capacity

" Microprobe

MOSSBAUER STANDARDS

NEUTRON DENSITY MONITOR WIRE

Cobalt in aluminum

NICKEL

Alloys

Chip form

Solid form

Coating thickness on brass on steel Fuel oil Metallo-organic compound

Oxides

Radioactivity

RIOBIUM

Radioactivitv NITRIC OXIDE

In nitrogen

NITROGEN IN

Cast iron Ingot iron

Steel Titanium Zirconium NONFERROUS ALLOYS

NUCLEAR MATERIALS

Neutron density monitor wire Plutonium assay Plutonium isotopic Uranium assay Uranium isotopic

OIL

Nickel and vanadium in Sulfur in Trace elements in ORES

Bauxite Copper

Fluorspar

Iron Lithium Molybdenum

Phosphate rock Tungsten

Zinc OXALIC ACID

Radioactivitv OXIDIMETRY

Arsenic trioxide Potassium dichromate Sodium oxalate OXIDES

Iron Nitrogen Titanium Uranium

Zinc (rubber compounding)

OXYGEN IN

Ingot iron Nitrogen

Steel Titanium Zirconium PAINT, LEAD-BASED

PAPER

Faded strips Light sensitive PARTICULATE, URBAN

PERMEANCE, WATER VAPOR

PERMEATION TUBES

Nitrogen dioxide

Sulfur dioxide PERMITTIVITY

pD STANDARDS

Disodium hydrogen phosphate Potassium dihydrogen phosphate

Sodium bicarbonate Sodium carbonate pH STANDARDS

Acid potassium phthalate Borax Disodium hydrogen phosphate Potassium dihydrogen phosphate

Potassium hydrogen tartrate Potassium tetroxalate Sodium bicarbonate Sodium carbonate Tirs(hydroxymethyl)aminomethane

Tris(hvdroxvmethvl)aminomethane HC1

PHOSPHATE

Ammonium dihydrogen Potassium dihydrogen

See, pH standards Rock

PHOSPHORS

PHOSPHORUS

Ferro (steelniaking alloy) Metallo-organic compound

PHOTOGRAPHIC

Microcopy resolution lest chart Step tablets PLASTIC (See, Polymer)

Cellular

31
Polyester film for oxygen transmission PLATINUM

Doped, wire

High-purity, wire Magnetic susceptibility Thermuelement PLUTONIUM

Metal assay Standard matrix

Sulfate tetrahvdrate POLONIUM

Radioactivity

POLYESTER PLASTIC FILM

POLYETHYLENE

POLYMER

Molecular weight

Oxygen transmission

Permittivity POLYSTYRENE

POTASSIUM

Acid phthalate Chloride (clinical) Bichromate (clinical) Dichromate (oxidimetnc)

Iodide (spectrophotometnc)

Metallo-organic compound

See, Fertilizer See, Iron activity POWDER DIFFRACTION STANDARDS

a-alumina Cerium oxide Chromium oxide

Rutile

Silicon Zinc oxide PRIMARY CHEMICALS

Arsenic trioxide Benzoic acid Boron

Dextrose Plutonium metal Plutonium sulfate tetrahydrate Potassium chloride Potassium dichromate

Potassium acid phthalate

Rubidium chloride Sodium oxalate Strontium carbonate

Sucrose Tris(hydroxymethyl)aminomethane

Uranium metal Uranium oxide PROMETHIUM

Radioactivity

PROPANE

QUARTZ

«» for HF solution calorimetry Cuvette for spectrophotometry

Filter media, on RADIOACTIVITY STANDARDS

Alpha-particle

Beta-particle and gamma ray gas

Beta-particle, gamma-ray, and electron-capture solutions Contemporary standard for carbon-14 dating laboratories Environmental Gamma-ray "point-sources"

Mixed radionuclides Radium gamma-ray solutions Radium solutions for radon analysis

RADIUM

Radioactivity

RADON

Radioactivity

REFRACTIVE INDEX

Glass

Silicone liquids 2,2,4-Trimethylpentane Toluene REFRACTORY MATERIALS

RESEARCH MATERIALS

Aluminum ultra purity Copper heat capacity Glass for microanalysis

Phosphors

River sediment Tuna, Albacore RESISTIVITY

Electrical Silicon RHENIUM

Isotopic and assay RUBBER

RUBBER COMPOUNDING

RUBIDIUM

Isotopic

SAPPHIRE

Enthalpy and heat capacity Thermal expansion

SEDIMENT

Estuarine

River, environmental

River, radioactivity SELENIUM

Metal

Radioactivity

SILICON

Ferro (steelmaking alloy) Isotopic

Metallo-organic compound

Refractories (SiCh)

Resistivity X-ray diffraction, powder

SILICONE LIQUIDS (refractive index)

SILVER

Alloys (microprobe)

Isotopic reference Metallo-organic compound

SIZING STANDARDS

Calibrated glass spheres Turbidimetric and fineness (cement) SMOKE DENSITY CHAMBER

STANDARDS

SODIUM

Bromide (isotopic) Metallo-organic compound

Oxalate

Radioactivity

See, Ion-activity SOLDER

Chip form

Solid form SOLIDS, ANALYZED

SPECTROPHOTOMETRIC STANDARDS

Didymium-oxide glass filters Glass filters Liquid filters Metal on quartz filters Potassium dichromate

Potassium iodide (stray light) Quartz cuvette

32
Quinine sulfate dihvdrate STAINLESS STEEL

Chip form

Resistivity Solid form STEELMAKING ALLOYS

Calcium molybdate

Ferrochromium

Ferroniobium

Ferrophosphorus

Ferrosilicon

Silicon, refined STEEL, THERMAL CONDUCTIVITY

STEELS, CAST

STEELS, CHIP FORM

High alloy Low alloy Low alloy, special Plain carbon

Stainless Tool STEELS, GAS-IN

STEELS, GRANULAR FORM

STEELS, SOLID FORM

Cast High temperature alloy Low alloy Low alloy, special Maraging

Oxygen

Stainless Tool STEP TABLETS

Photographic

X-ray

STRONTIUM

Isotopic reference Metallo-organic compound

Radioactivity

SUCROSE

Primarv chemical SULFUR

Elemental (rubber compounding)

in residual fuel oils

in coal SUPERCONDUCTIVE THERMOMETRIC

FIXED POINT DEVICES

SURFACE FLAMMABILITY

TAPE, MAGNETIC-SECONDARY

REFERENCE

Cartridge

Cassette Reel TEMPERATURE (See, HEAT

STANDARDS)

Calorimetry

Differential thermal analysis Heat source THERMAL CONDUCTIVITY

THERMAL EMITTANCE STANDARDS

THERMAL EXPANSION

THERMOCOUPLE MATERIALS

THERMOMETERS

THORIUM

Radioactivity

TIN

Chip form

Coating thickness Freezing point

Metallo-organic compound

TITANIUM

Chip form

Dioxide

Gases-in Metallo-organic compound

Solid form

Unalloyed for oxvgin

TRACE ELEMENTS

Biological matrices Environmental

Fuels Glass matrices Metallo-organics

TRICHLOROETHYLENE ON

CHARCOAL

TUNGSTEN

Carbide

Concentrate

Electrical resistivity Microprobe Thermal conductivity Thermal expansion

TURB1DI METRIC AND FINENESS

STANDARD

URANIUM

Isotopic and assay Metal Oxide

Depleted

Enriched Primary standard VANDIUM

Fuel oil, in Metallo-organic compound

VAPOR PERMEANCE. WATER

VAPOR PRESSURE STANDARD

VISCOSITY STANDARDS

Glass WATER, TRACE ELEMENTS IN

WATER VAPOR PERMEANCE

m-XYLENE ON CHARCOAL

X-RAY STEP TABLET

X-RAY DIFFRACTION

Silicon powder

YTTRIUM

Radioactivity

ZINC

Chip form

Concentrate, ore Freezing point

High purity Intermediate purity Metallo-organic compound

Oxide (rubber compounding)

Solid form

Spelter modified ZIRCONIUM

Chip form

Solid form

33

Appendix II. Certificates for Clinical Laboratory Standards

U.S. Department of Commerce . juanita^.Kreps (listed in numerical order).

National Buresw ol Standards

Ernest Amblier, Director Rational £5uram of j^tandartte

Certificate

Standard Reference Material 900

Antiepilepsy Drug Level Assay Standard

This Standard Reference Material (SRM) is certified for concentrations of four antiepilepsy drugs—phenytoin,

ethosuximide, phenobarbital, and primidone—in a processed human serum base. It is intended for use ( 1 ) in the

calibration and standardization of procedures employed in clinical laboratories for the determination of these drugs in serum, and (2) for the critical evaluation of working or secondary reference solutions prepared either in- house or supplied commercially. The certified concentrations apply to the four materials supplied, after each serum is reconstituted, following the procedures described in "Instructions for Use."

Concentration Level, ngjmL

Drug Toxic Therapeutic Subtherapeutic Blank

Phenytoin 60.7 ± 0.9 16.7 ±0.3 4.2 ± 0.1 0

Ethosuximide 174.7 ± 0.6 75.9 ± 0.5 11.8 ±0.4 0

Phenobarbital 103.6 ± 0.3 21.6 ±0.2 5.3 ± 0.2 0

Primidone 18.6 ±0.7 8.1 ±0.2 3.6 ± 0.

1

0

The uncertainties represent one standard error for the above certified values. The imprecisions observed both

within and between the liquid and gas chromatographic analyses used for this certificate are included in the standard errors. The statistical analyses were made by R. C. Paule and J. Mandel.

The modified human serum base was processed, vialed and packaged by Microbiological Associates, Walkersville, Maryland. Analyses leading to certification were performed in the NBS Center for Analytical Chemistry

by R. Angeles, R. G. Christensen, A. Cohen, B. Coxon, D. Enagonio, D. J. Reeder, and L. T. Sniegoski.

Valuable correlating analyses were also performed by: E. Berman, Cook County Hospital, Chicago, Illinois; K. Dudley, The University of North Carolina at Chapel Hill; and H. J. Kupferberg, National Institute of

Neurological and Communicative Disorders and Stroke, NIH.

The overall direction and technical measurements leading to the certification were under the chairmenship of D. J. Reeder and R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by R. Keith Kirby.

Washington, D.C. 20234 J. Paul Cali, Chief

April 5, 1979 Office of Standard Reference Materials

(Editorial Revision of Certificate dated 11-17-78) (over)
The analytical techniques used in the certification of this Standard Reference Material were liquid chromatography, calibrated with external standards, and gas chromatography, calibrated by bracketing and internal standards. The drug concentrations have also been determined with commercially available reagents that are based on immunoenzymatic assay principles. The mean values obtained by this methodology were close to the

certified values; however, the precision was not sufficient to be included in the certification data.

The Standard Reference Material is intended for "in vitro" diagnostic use only.

WARNING: HANDLE AS IF CAPABLE OF TRANSMITTING HEPATITIS. Source material from

which this serum base was derived was found non-reactive for Hepatitis B antigen when tested with licensed third-generation reagents. No known test method can provide complete assurance that products derived from

human blood will not transmit hepatitis.

Instructions for Use

This Standard Reference Material is supplied as a set of four different freeze-dried preparations. They should

be stored at refrigerator temperature (~ 4 °C) and should not be exposed to sunlight or ultraviolet radiation. Under such storage, the SRM is expected to be stable for at least 2 years. Samples of this SRM will be

monitored. Should statistical evidence indicate a degradation of the certified properties purchasers will be

notified by NBS. It is recommended that the material not be used after 2 years from the date of purchase.

For use, it is necessary to reconstitute the freeze-dried materials with high-purity water.* When a vial is opened, remove the rubber stopper carefully so as not to dislodge any serum particles that may adhere to the stopper.

Add 5.0 mL of water to the vial from a calibrated volumetric pipet or other dispenser of known accuracy. Replace the stopper and allow the contents to stand at room temperature for 20-30 min. Finally, mix the contents by gentle swirling. DO NOT shake vigorously because denaturation and frothing may result.

After reconstitution, the contents should be used within one day; otherwise, the certified values cannot be

assured. Storage of the reconstituted material beyond 1 2-24 hours may result in deterioriation of the drugs or in degradation of the serum base.

This Standard Reference Material has been measured and certified at the Laboratories of the National Bureau

of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of this Standard Reference Material is November 17, 1978.

•Equivalent to Type II reagent grade water as specified by the College of American Pathologists (CAP).

SRM 900

3^
SEE ADDENDUM

^National ^ltreatt of j^tattdartfe

Certificate

Standard Reference Material 909

Human Serum

This Standard Reference Material (SRM) is intended for use in evaluating the accuracy of clinical procedures for the determination of specified constituents in serum, in calibrating instruments and equipment used in these procedures, and

in validating working or secondary reference materials. CERTIFIED VALUES OF ANALYTES: The concentrations of the analytes were determined by methods having the

highest accuracy, i.e., definitive methods. The certified values are given in two ways, depending on whether

reconstitution is done with or without weighing the freeze-dried serum contents of a vial. Concentration values having

smaller uncertainties may be obtained by weighing the freeze-dried serum and multiplying this mass by the certified concentration values of the analytes per unit mass of dried serum. These certified values appear in Table 1. When the contents of a vial are not weighed, the mean values for the certified concentrations and their uncertainties should be used. These values, which apply to all vials of reconstituted SRM 909, appear in Table 2.

U. S. Department of Commerce

Philip M. Klutznick

Secretary

National Bureau of Standards

Ernest Ambler, Director

NOTICE AND WARNINGS TO USERS

USE: HANDLE AS IF CAPABLE OF TRANSMITTING HEPATITIS! Although this product was tested with

licensed third generation reagents and found nonreactive for the presence of hepatitis B surface antigen (HBsAG), no known test method can offer assurances that products derived from human blood will not transmit hepatitis.

SRM 909 IS INTENDED FOR "IN VITRO" DIAGNOSTIC USE ONLY.

STORAGE: The freeze-dried serum should be stored in a refrigerator at a temperature between 2 and 8° C. It should not be frozen nor exposed to sunlight or ultraviolet radiation. Under the recommended storage conditions, this SRM is expected to be stable for at least one year; should evidence indicate a more rapid degradation of the certified properties,

purchasers wi'l be notified by NBS. The material is not certified for use after one year from date of purchase.

The statistical analysis of the data was performed by K.R. Eberhardt of the Statistical Engineering Division.

The overall direction and technical measurements leading to the certification were under the chairmenship of E. Garner,

H.S. Hertz, T.J. Murphy, D.J. Reeder, R. Schaffer and E. White V.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard Reference

Material were coordinated through the Office of Standard Reference Materials by R. Alvarez.

Washington, D.C. 20234 George A. Uriano, Chief

September 15, 1980 Office of Standard Reference Materials

January 13, 1981 (revision) (over)

37
Instructions for Use

HANDLE AS IF CAPABLE OF TRANSMITTING HEPATITIS! SRM 909 is supplied as a set of six vials of

freeze-dried human serum and six vials of high-purity, diluent water for use in reconstituting the serum. Two procedures for reconstituting SRM 909 are described. Selection of a procedure depends on the uncertainties

required for the concentrations of the analytes. If lower uncertainties than those shown in Table 2 are required, the

freeze-dried serum contents of a vial must be weighed as described in Procedure A.

Procedure A. Reconstitution with weighing of the freeze-dried serum: Completely remove label and adhesive by

scraping the vial and then wiping it with a tissue moistened with a solvent, such as acetone or ethanol. Scratch an

identification on vial. Remove metal closure and lightly tap bottom of vial to dislodge any serum particles adhering to the

stopper. Dislodge stopper to equalize air pressure, then replace, wipe surface of vial, and weigh to the nearest 0.1 mg.

(Use a clean empty vial of the same size as a tare.) Carefully remove stopper to avoid possible loss of serum particles. Use

a Type 1 Class A volumetric transfer pipet or other dispenser of known accuracy to slowly add 10.00 ± 0.02 mL of the

diluent water at 20 - 25 °C to the sides of the vial while continually turning the vial. Replace stopper, swirl vial two or

three times, and let stand for 10 minutes. Mix contents by gently swirling, let stand for approximately 30 minutes, swirl again, let stand 10 minutes, and finally invert the vial several times. Do NOTshake vigorously because this will cause

frothing. Total time for reconstitution is approximately 1 hour. After reconstitution, use contents as soon as possible. If not used immediately, store between 2 and 8 °C until ready for use, preferably within 8 hours. After the reconstituted serum has been used, clean and dry the vial and its stopper. Reweigh after replacing stopper. The tare is reweighed at the same time to compensate for changes in temperature and humidity. The mass of dry serum is given by the difference

between the original and final weighings.

The concentration of an analyte, after the contents of a vial is weighed and reconstituted with 10.00 mL of diluent water,

is calculated by multiplying the mass of freeze-dried serum, in grams, by the certified concentration of the analyte per gram of freeze-dried serum given in Table 1. For example, if the mass of freeze-dried serum in a vial is 0.8703 g, the concentration of uric acid in this vial would be:

0.5681 mmol-L"V x 0.8703 g = 0.4944 mmol/L.

The uncertainty is also calculated similarly and for this example would be:

0.0050 mmol-L~ V x 0.8703 g = 0.0044 mmol/L.

Table 1. Certified Analyte Concentrations and Uncertainties per Gram of Freeze-Dried Serum after Reconstitution of

SRM 909 according to Procedure A.

1 2 3 Analyte Concentration, per gram, Uncertainty, per gram,

mmol L

' g

1 mmolL '-g1

Calcium3 3.560 ±0.013

Chloride

2 128.0 ± 1.5 Glucose

3 7.811 ±0.095

Lithium

3 1.945 ±0.033

Potassium

3 4.1546 ±0.0098

Uric Acid

3 0.5681 ±0.0050

1. Analytical Methods

a. Isotope dilution mass spectrometry.

2. The certified concentrations apply to reconstituted serum at room temperature (20-25 °C).

3. The uncertainties represent 95%/99% statistical tolerance limits for the concentrations per gram of dry serum reconstituted

with 1 0.00 mL of high-purity water. The tolerance limits are constructed so that, at a confidence level of 95%, they will contain

the concentration/ mass ratios for at least 99% of the vials.

Page 2 SRM 909

38
Procedure B. Reconstitution of SRM 909 without weighing freeze-dried serum: Remove metal closure and lightly tap

bottom of vial to dislodge any serum particles on stopper. Carefully remove stopper to avoid possible loss of serum

particles. As described in Procedure A, reconstitute with 10.00 ± 0.02 mL of the diluent water, and use immediately or

store between 2 and 8 °C until ready for use, preferably within 8 hours. Table 2 gives the certified concentrations of the

constitutents and the tolerance limits for use with this procedure.

Table 2. Certified Concentrations and Uncertainties for Analytes in Reconstituted SRM 909 for Use with Procedure B.

Analyte

1 Concentration2

, Uncertainty

3

,

Calcium

mmol-L

3.02

mmol-L

+0.17

-0.06

i

+7

-3

+0.44

-0.20

+0.12

-0.06

+0.19

-0.06

+0.031

-0.012

Chloride 108

Glucose

3 6.62

Lithium

3 1.65

Potassium

3 3.52

Uric Acid

3 0.481

1. Analytical Methods:

a. Isotope dilution mass spectrometry.

2. The certified concentrations apply to reconstituted serum at room temperature (20-25 °C).

3. The uncertainties represent 95%/ 95% statistical tolerance limits for the concentrations, and reflect the combined

effects of measurement imprecision and the variability of the mass of dry serum among vials. They are constructed so

that, at a confidence level of 95%, they will include the concentrations of at least 95% of all vials of SRM 909, when

reconstituted according to Procedure B.

The major source of uncertainty in the certified concentrations shown in Table 2 is caused by vial-to-vial variability in the mass of freeze-dried serum. Information on the relation between mass variability and concentration was obtained

directly during the course of experimentation by weighing the contents ofeach vial as an intermediate step in determining

the concentration of an analyte. Supplementary information on the variability in mass was obtained from a differential refractometry experiment in which over 1 70 vials were analyzed. The data obtained from these two sources indicate that the distribution of masses is non-Gaussian and skewed in the direction of high mass. The largest two masses encountered were 5.2% and 2.7% above the mean mass, 0.8469 g. All other masses were contained in an interval from 1.5% below to 1.8% above the mean.

Source of Material: The human serum for SRM 909 was processed, vialed, and packaged by Hyland Division, Travenol

Laboratories Inc., Round Lake, Illinois.

Analyses were performed in the NBS Center for Analytical Chemistry by I.L. Barnes, K.A. Brletic, R.G. Christensen, A. Cohen, J. W. Gramlich, W.R. Kelly, L.R. Machlan, J.R. Moody, L.J. Powell, L.T. Sniegoski, and M.J. Welch (Research

Associate, College of American Pathologists).

This Standard Reference Material has been measured and certified at the Laboratories of the National Bureau of

Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standards Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D C. 20234

The date of issuance and certification of this Standard Reference Material is September 15, 1980.

Page 3 SRM 909

39
U. S. Department of Commerce

Philip M. Klutznick

Secretary

National Bureau of Standards

Ernest Ambler, Director

Addendum to

^attmtal ^Bureau of Standards

Certificate of (Analyst*

Standard Reference Material 909

Human Serum

ADDITIONAL CERTIFICATION

The following certified values are to be added to Tables 1 and 2.

Table 1. Certified Analyte Concentrations and Uncertainties per Gram of Freeze-Dried Serum after Reconstitution of

SRM 909 according to Procedure A.

Analyte

1 Concentration,2 per gram, Uncertainty,

3 per gram,

mmol-L -g

1 mmol-L ' g1

Cholesterol

3 4.346 ±0.030

Magnesium3 1.425 ±0.072

Table 2. Certified Concentrations and Uncertainties for Analytes in Reconstituted SRM 909 for Use with Procedure B.

Analyte

1 Concentration2

, Uncertainty

3

, mmol-L 1 mmol-L 1

Cholesterol

3 3.68 +022

-0.08

Magnesium3 1.21 +0.14

-0.10

Washington, D.C. 20234 George A. Uriano, Chief

November 14, 1980 Office of Standard Reference Materials

40
IJ. S. Department of Commerce

Malcolm Bald rige "Secretary {

National Burm*or$tandards

Ernest l<\mbler, pSrector Rational ^mmvc of jltantlard*

Certificate of ^nalgsi*

Standard Reference Material 910

Sodium Pyruvate

This Standard Reference Material (SRM) is certified as a chemical of known purity. It is intended primarily for use in the

calibration and standardization of procedures for pyruvate, lactic dehydrogenase, and glutamic-pyruvic transaminase

determinations in clinical analyses, and for critical evaluation of the routine working or secondary reference materials

used in these procedures.

Sodium Pyruvate

1 98.7

Sodium 2-hydroxy-4-keto-2-methylpentanedioate

1 0.9 (parapyruvate)

2 Moisture (0.28) weight percent

Methanol (0.21) weight percent

Water-insoluble matter (0.004) weight percent

'"The certified pyruvate and parapyruvate concentrations were obtained by taking weighted averages for results from

two separate methods of analysis. Measurements were made at NBS using high-performance liquid chromatography

(HPLC) and high-field, proton NMR spectroscopy at 400 MHz. For each certified average, the relative weights were

calculated based on the internal (within-method) and the between-method variance components. The standard errors of

the certified concentrations were also calculated using combinations of both the variance components. The individual

results for each method of analysis were: NMR - pyruvate, 98.83 ± 0.05; parapyruvate, 0.68 ±0.05; HPLC - pyruvate,

98.50 ± 0.03; parapyruvate, 1.02 ± 0.03 weight percent.

2Values in parentheses are not certified because they were determined by one method only.

All reported uncertainties are stated as plus or minus one standard error of the listed value.

NOTICE AND WARNINGS TO USERS

This Standard Reference Material is intended for "in vitro" diagnostic use only.

±0.2 weight percent

±0.2 weight percent

Storage:

SRM 910 should be stored in the tightly capped bottle at 2-6 °C. It should be allowed to warm to room temperature

before opening. Under proper storage, this material should be stable for at least 5 years. If the purity of the material

degrades beyond the limits certified, purchasers will be notified by NBS. This material is not certified for use after 5 years from date of purchase.

The sodium pyruvate used for this SRM was obtained from the Sigma Chemical Company, St. Louis, Missouri.

Analyses and physical determinations were performed at NBS in the Organic Analytical Research Division by B. Coxon,

A. Cummings, J. Lee, S. Margolis, and L. Sniegoski.

The statistical analysis of the data was made by R. Paule, NBS National Measurement Laboratory.

The overall direction and coordination of the technical measurements leading to the certification were under the

chairmanship of S. Margolis and B. Coxon.

The technical and support aspects involved in the preparation, certification, and issuance of this Standard Reference

Material were coordinated through the Office of Standard Reference Materials by R. Alvarez.

Washington, D.C. 20234 George A. Uriano, Chief

May 15, 1981 Office of Standard Reference Materials

(over)

41
Liquid chromatography of 3-mg samples of this SRM, dissolved in water, was performed by using a 1 50 x 0.9 cm column

packed with Sephadex G- 1 5, operated at a pressure of 500 kPa. The eluant was 0.03 mol/ L sodium phosphate buffer at pH 8.0. Elution was monitored by measurement of refractive index and transmittance at 254 nm. A major peak and two

minor peaks with retention times of 0.65 and 0.80 relative to the major peak were detected. The material corresponding

to each peak was collected, lyophilized, checked for chromatographic purity by chromatography on a Sephadex G-15

column, and characterized by both proton and carbon- 13 ( C) NMR spectroscopy. Chromatography on Sephadex

G-15 of chromatographic fractions before and after lyophilization showed that no changes occurred on lyophilization

of the separated materials nor did new products form during the process of chromatography.

The major peak exhibited proton and

13 C NMR spectra that are characteristic of sodium pyruvate: at pH 6 and pH 8, proton NMR indicated that approximately 7.5 percent and 4.7 percent, respectively, of the pyruvate is hydrated at the

C-2 position. The impurity at the relative retention time 0.80 (the larger of the minor peaks) appears to be a single

compound which exhibits an NMR spectrum characteristic of the linear form of the parapyruvate. The impurity at the

relative retention time of 0.65 (present at only trace levels) was located at the void volume of the column, and NMR

analysis of the lyophilized material suggested that this material was a mixture of oligomers of sodium pyruvate.

The parapyruvate content was found to be 0.68 ± 0.05 percent from methyl proton NMR peak intensities and

1 .02 ± 0.03 percent from chromatographic measurements. The reasons for the discrepancy in the estimates by NMR and

HPLC is unclear. It does not appear to be attributable to a contaminant in that HPLC peak, to differences in the

extinction coefficients of the pyruvate and parapyruvate, or to differences in the intensities of the NMR signals of the

methyl group of these compounds.

From signal measurements,

13C NMR spectroscopy indicated the presence of less than 0.6 mol percent of organic

impurities other than parapyruvate and methanol in the SRM. Proton NMR spectroscopy at 400 MHz was performed

to determine the content of parapyruvate and methanol. The spectroscopy was performed at ambient temperature using

a data set of 16,384 points, a 30° pulse, and a relaxation delay of 6.26 s between pulses.

Samples for proton NMR analysis were prepared by dissolving 240 mg of the SRM in 0.5 mL of 9: 1 v/v water-deuterium

oxide. No significant differences in parapyruvate or methanol content were observed for solutions that were analyzed by

signal averaging over periods ranging from 7 minutes to 3 hours. After drying the SRM at 93 °C and 2.5 kPa for 15 hours, the methanol content was 0.16 percent, indicating that methanol is not readily removed by such treatment.

The structure of the parapyruvate was proven by means of

13C NMR spectroscopy at 22.6 MHz using a data set of

8, 192 points, a 30° or 45° pulse, a relaxation delay of 5 s, and solutions prepared by dissolving 1-g portions of the SRM

in 2-mL aliquots of 9: 1 v/v water-deuterium oxide. C spectral assignments were confirmed by the use of off-resonance

proton decoupling techniques, proton coupled spectra, and measurements of the spin-lattice relaxation times of sodium

pyruvate and parapyruvate, using the fast inversion recovery method.

The ultraviolet absorption spectrum of sodium pyruvate in distilled water at pH 5.9 exhibited an absorbance maximum

at 316 nm and a minimum at 289 nm. The molar extinction coefficient at 316 nm is 18. 14 ± 0.04 L mol cm . Parapyruvate exhibited an absorbance maximum at 326 nm and a minimum at 301 nm. The molar extinction coefficient is 25 L mol cm . The absorbance of the SRM above 400 nm is less than 0.3 percent of the absorbance at 316 nm.

Microchemical analysis yielded these values, in percent: carbon, 32.64 ± 0.08; hydrogen, 2.84 ± 0.02; sodium,

20.73 ± 0.03; and oxygen, 43.49 ± 0.06. Calculated percentages based on C3H3 Na03 are 32.74, 2.74, 20.89, and 43.91,

respectively.

The homogeneity of the SRM, as determined by liquid chromatography and by proton and

13C NMR spectroscopy, was found to be satisfactory.

This SRM is intended for "in vitro" diagnostic use only.

This material is for use as a standard in clinical chemistry. Stock solutions should be prepared daily with distilled water. The pH of a solution of the SRM in distilled water at a concentration of 250 mg/mL is 5.90 ± 0.06. Such solutions are

stable for several weeks in the frozen state at -20 °C. However, at 20 °C and at an initial pH 5.90, the concentration of

parapyruvate doubles in five days, and triples within 24 hours if the pyruvate is dissolved in 0.25 mol/L potassium

phosphate at pH 8.0 and 20 °C. With the same solvent adjusted to pH 9, 50 percent of the pyruvate dimerizes within

24 hours.

42
U. S. Department of Commerce

Philip M. Klutznick

Secretary

National Bureau of Standards

Ernest Ambler, Director

Rational ^ttram of jltandartts

Certificate of (Attaints

Standard Reference Material 911a

Cholesterol

A. Cohen, W. May, and R. Schaffer

This Standard Reference Material is certified as a chemical of known purity. It is intended primarily for use in the calibration and standardization of procedures for cholesterol determinations employed in clinical analysis

and for routine critical evaluation of the daily working standards used in these procedures.

Purity 99.8 ± 0. 1 percent

The selenium dioxide test for lathosterol [I] was negative.

The purity was determined by the use of liquid chromatography, gravimetric recovery, and thin-layer

chromatography. The most recent monitoring of purity, completed in February 1 980, was performed by the use of mass spectrometry, capillary column gas chromatography, and thin-layer chromatography. The results showed nonsignificant changes in the levels of impurities.

This Standard Reference Material should be stored in the tightly capped bottle in a desiccator at 0°C. It should

be allowed to warm to room temperature before opening. If this procedure is followed, drying is unnecessary.

The cholesterol used for this Standard Reference Material was obtained from the J. T. Baker Chemical

Company of Phillipsburg, N.J. Analyses and physical determinations were performed by A. Cohen, S. P. Cram,

E. R. Deardorff, D. Ft. Freeman, H. S. Hertz, W. May, R. Schaffer, W. P. Schmidt, C. P. Talley, and T K. Taylor. The additional analyses were performed by S. Chesler, B. Coxon, L. Sniegoski, and E. White V.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by T. W. Mears.

Washington, D.C. 20234 George A. Uriano, Chief

March 5, 1980 Office of Standard Reference Materials

(Revision of Certificate dated 11-1-74) (over)

43
Liquid chromatography was performed on this material using a column packed with poly-2-methyl-5-vinylpyridine/divinylbenzene. The sample size was exactly 1 g cholesterol (measured to the nearest 0.1 mg). The

eluant was chloroform and the progress of the elution was monitored by the measurement of transmittance

of effluent at 254 nm. Two peaks due to impurities were detected at 0.7 and 0.8 retention time relative to the

cholesterol peak. Recovery of the sample by gravimetry corrected for the blank due to column bleed, was

100. 04 percent. The weighed effluent residues were examined by thin-layer chromatography on 250-/xm layers of

silica gel using 1:1 (v/v) ethyl acetate—heptane as developing solvents. Spraying with 1:5 (v/v) sulfuric acid—

methanol followed by heating to 1 10 °C revealed two impurities at migration distances of 1.53 and 1. 16 relative to that of cholesterol. These impurities, found in fractions representing a combined weight of 0.08 percent of

the intial cholesterol, corresponded to the impurities detected by prior liquid chromatography at retention times

of 0.7 and 0.8, respectively.

Gas-chromatographic examination, using Gas-Chrom Q treated with 3 percent OV- 1 7 as the stationary phase at 240 °C, showed impurity peaks at retention times 0.5, 0.80, and 1.2 relative to cholesterol.

Non-destructive neutron activation analysis of cholesterol samples sealed in high-purity quartz ampoules prior

to irradiation indicated a bromine content of 12 /ug/g* a chlorine content of 0.7 jug/g, and an iodine content of

less than 0.8 Mg/g- The estimated accuracy of these measurements was within 20 percent.

The infrared-absorption spectrum of SRM 91 la was the same as that of SRM 91 1. The ultraviolet-absorption

spectrum of SRM 91 la (4 percent solution in methylene chloride) showed very little absorption in the range

400 to 240 nm. This absorption is less than that exhibited by SRM 91 1 under similar conditions.

The melting point of this material, measured in a sealed tube under vacuum, is 149.0 to 149.4 °C. The specific

rotation [a] 20 is -0.700 rad (-40.1°) (c, 1; CHCI3). Microchemical analysis found carbon 83.86 ± 0.05 wt. percent, hydrogen 12.00 ± 0.05 weight percent; theoretical percentages based on C27H46O are 83.87 and 1 1.99, respectively.

Heating the material at 100 °C at 3Pa (0.02 mm Hg) resulted in a nearly constant loss in weight of 0.01 percent

per hour over a 1.5 day period. Such a volatilization may be related to degradation and /or sublimation

processes.

Precautions

This Standard Reference Material is intended for "in vitro" diagnostic use only.

The Standard Reference Material should be stored in a tightly closed bottle kept in a refrigerator or freezer.

It should not be subjected to heat, direct sunlight, or artificial sources of ultraviolet radiation. For extended

periods of storage after opening, it is recommended that the material be kept at or below - 1 5

0 C in a desiccator

under inert gas. Experience at NBS, where the material is stored under inert gas at - 1 5 °C, indicates the material

may be stable for 10 years. If the purity of control material at NBS degrades beyond the limits certified,

purchasers will be notified by NBS. However, if the material is stored under ordinary laboratory conditions in a

refrigerator, it is recommended that the material should not be used after 3 years from the date of purchase. If

it is stored in the dark at room temperature, it is recommended that the material not be used after six months

from the date of purchase.

SRM9Ila

44
This material is for use as a standard in clinical chemistry. A stock standard solution of cholesterol in ethanol

(5 mmol/L) may be prepared by dissolving 194mgof SRM 91 la in 50 mL of warm absolute ethanol in a 100-mL

volumetric flask, allowing the solution to cool, and diluting to exactly 100 mL with ethanol [2]. It should be

stored in an all-glass, tightly stoppered bottle at 0 °C. Under such conditions this solution should be stable

for about 4 months [3].

Because methods for the determination of cholesterol vary widely, users should follow the instructions included

with each method for preparing the working standard solution from the stock standard solution.

Solutions of cholesterol in glacial acetic acid gradually form cholesteryl acetate when stored and therefore may

cause errors in calibration [4].

All constituted solutions of cholesterol should be clear and display no turbidity.

References:

[1] Fieser, L. F. , Cholesterol and Companions. Ill, Cholestanol, Lathosterol and Ketone 104, J. Am. Chem.

Soc. 75^4395 (1953).

[2] Fundamentals of Clinical Chemistry, N. Tietz, editor, p. 358, W. B. Saunders Co., Philadelphia, Pa. (1970).

[3] Henry, R. D., Clinical Chemistry, Principles and Technics, p. 854, Hoeber Medical Division, Harper &

Rowe, New York, N.Y. (1967).

[4] Klein, B., and Kleinman, N.B., Esterification of Cholesterol in Glacial Acetic Acid., Clin. Chem. 20, 90

(1974).

This Standard Reference Material has been measured and certified at the laboratories of the National Bureau

of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of this Standard Reference Material was June 6, 1974.

SRM 911a

45
U.S. Jepartrrtent of Commerce

Juanita Krepa

Secretary

National Burau or Standards

Ernest Ambler. Director

^National ^nttnn of j^tattdartte

Certificate of (Analysis

Standard Reference Material 912a

UREA

This Standard Reference Material is certified as a chemical of known purity for use in the calibration and

standardization of procedures employed in clinical analysis.

Purity 99.9 ± 0.1 percent

Moisture 0.02 ± 0.003 percent

Biuret 0.02 ± 0.02 percent

Ash 0.001 ± 0.0007 percent

Insoluble matter 0.0001 ± 0.00005 percent

The purity value has an estimated uncertainty of 0. 1 percent. The errors of the moisture, biuret, ash, and

insoluble matter are given as two standard errors of the mean.

The urea used for this Standard Reference Material was obtained from Fluka AG, Switzerland. Analyses were performed by R. G. Christensen, B. Coxon, A. L. Cummings, J. Lee, D. J. Reeder, F. J. Savluk, and

L. T. Sniegoski, of the Organic Analytical Research Division.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of B. Coxon and D. J. Reeder.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by R. Alvarez.

Washington, D.C. 20234 George A. Uriano, Chief

November 16, 1979 Office of Standard Reference Materials

(over)

46
Differential scanning calorimetry [1] of the Standard Reference Material indicated a purity of 99.97 ±0.01 mole

percent (exclusive of moisture content).

The moisture content of the Standard Reference Material was determined separately by Karl Fischer titration of

samples ranging from three to ten grams.

Biuret was estimated spectrophotometrically by use of a 6 mol l.

1 solution of urea in aqueous, alkaline

nickelous sulfate measured at its absorption maximum at 461 nm[2]. This determination was calibrated against

dilute solutions of crystalline biuret, the purity of which was established by high resolution, pulse-Fourier

transform, carbon- 1 3 nuclear magnetic resonance (

l3CNMR) spectroscopy of a 1 mol • L

1 solution of the biuret

in methyl sulfoxide-d.6.

Measured in a 2-cm cell, a 50 percent (wt / vol) solution of urea in water showed strong absorption ( 1 . 87 ± 0.0 1 ) at 220 nm, a weak absorption (0.036 ± 0.001) at 280 nm, and a very weak absorption (0.006 ± 0.001) at 461 nm.

The sulfated ash content of the Standard Reference Material was determined by volatilization of 25 g samples in porcelain crucibles, followed by moistening of the residue with concentrated sulfuric acid, further volatilization,

and finally, ignition at 800 °C to constant weight.

Insoluble matter in the Standard Reference Material was determined by dissolution of 25 g samples in 100 mL

aliquots of water, followed by filtration of the briefly boiled solutions through tared crucibles which were then

dried at 110° C.

The homogeneity of the Standard Reference Material was verified by differential scanning calorimetry,

13C

NMR spectroscopy, melting point determination, and moisture determination by the Karl Fischer method.

Spectroscopy by C NMR of approximately lOmolL solutions of the urea in H20:D20 (9: 1 v/v), performed

by signal averaging of 1 2,000 scans at 22.6 MHz showed only a single

1

3

C resonance with a chemical shift, 5c, of

161.6 from external tetramethylsilane, and thus indicates the absence of organic impurities by this test.

The melting range of this Standard Reference Material is 133.0 to 134.0 °C, as measured in an open capillary

tube heated at 0.5 °C min"1

. A 10 percent (w/v) solution of this Standard Reference Material in water, free from carbon dioxide, showed a pH of 7.1 ±0.2 at 23 °C.

This Standard Reference Material is intended for "in vitro" diagnostic use only.

47
This material is intended for use as a standard in clinical chemistry. A standard solution containing 20 mg per

100 mL (0.2 mg per mL) of urea nitrogen may be prepared by weighing 0.429 g urea into a one-liter volumetric

flask and making to volume with ammonia-free distilled water. A few drops of ACS Reagent-Grade chloroform

is to be added as a preservative. The solution should be stored in a refrigerator [3]. The concentration of urea

nitrogen in this solution is approximately that of the normal level in serum. An alternate procedure [4] recommends 0.1 g sodium azide per 100 mL of solution as a preservative.

This Standard Reference Material should be stored in a well-stoppered container at room temperature

(30 °C or less). It should not be subjected to heat, moisture, or direct sunlight during storage. Refrigerated

storage is recommended, but the material should be allowed to warm to room temperature before opening the

container. Under proper storage, experience at NBS indicates this material to be stable for at least 5 years. If the

purity of the material degrades beyond the limits certified, purchasers will be notified by NBS. It is recommended that this material not be used after 5 years from the date of purchase.

The standard urea nitrogen solution (20 mg/ 100 mL), prepared as described above, is stable for 3 months when

refrigerated at 4 °C in a well-stoppered, all-glass container.

All constituted solutions of urea should be clear and without indications of bacterial growth of any kind.

References:

[1] Plato, C, and Glasgow, A.R., Jr., Anal. Chem. 41, 330 (1969).

[2] Reeder, D.J., and Savluk, F.J., unpublished method.

[3] Henry, R.D., Clinical Chemistry, Principles and Practice, pp. 262-276, Hoeber Medical Division, Harper&

Row, New York, N.Y. 10016 (1967).

[4] Tietz, N.W., Fundamentals of Clinical Chemistry, pp. 718-722, W. B. Saunders Co., Philadelphia, Pa. 19105 (1970).

This Standard Reference Material has been measured and certified at the laboratories of the National Bureau of

Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of this Standard Reference Material was November 1979.

48
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Roberta, Director

^fyttottal ^Bureau of j^tandartte

(Kerttficati? of JVnalusts

Standard Reference Material 913

URIC ACID

This Standard Reference Material is certified as a chemical of known purity. It is intended

primarily for use in the calibration and standardization of procedures for uric acid determinations

employed in clinical analysis and for routine critical evaluation of daily working standards used in these procedures.

Purity 99.7 percent

Volatile matter 0.14 percent

Ash 0.057 percent

The value of the purity has an estimated inaccuracy of 0.1 percent.

The ash was found to be composed principally of salts of sodium and potassium. Aluminum,

calcium, iron, phosphorus, and silicon were found in proportions estimated to be between 1 and 10

percent of the ash. Cobalt, copper, manganese, nickel, and zinc were each present to an extent not

exceeding 1 percent of the ash.

The uric acid used for this Standard Reference Material was obtained from the Pfanstiehl

Laboratories, Inc., of Waukegan, Illinois. Analyses were performed by I). P. Enagonio, R. A.

Paulson, W. P. Schmidt, V. C. Stewart, R. S. Tipson, and B. F. West of the Analytical Chemistry

Division.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard Reference Material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

Washington, D. C. 20234 J. Paul Cali, Chief

September 24, 1968 Office of Standard Reference Materials

Revised November 23, 1973

(over)

49
The uric acid used in this Standard Reference Material was found to be homogeneous by paper

and thin-layer chromatography with several solvent systems. This homogeneity was further verified

by gas-liquid chromatography of the trimelhylsilylated material.

Volatile material was determined by heating the sample overnight at I 10 °C.

An emission spectrometric analysis for metallic constituents in the ash from this Standard

Reference Material showed the following present as major constituents: sodium, potassium,

aluminum, calcium, iron, phosphorus, and silicon. Neutron activation analysis of the bulk Standard

Reference Material indicated the presence of the following approximate concentrations of elements:

sodium, 170 ppm; copper, 2.4 ppm, manganese, 0.028 ppm.

The ultraviolet absorption spectra of the material exhibited the following absorption maxima:

In lithium carbonate solution, pU - 7.6

at 292 nm,e max = 12,560 ± 10

at 236 nm, e max = 10,000 ± 80

In a glycine-buffered solution, pH = 9.6

at 292 nm,e max = 12,650 ±50

at 234 nm,e max = 9^90 ± 50

The measures of uncertainty given are the standard deviation of a single measurement. They should

not be considered to be a certified measure of inaccuracy for the extinction coefficients.

A 100—g sample of uric acid was extracted successively with 500 cm3 each of water, absolute

ethanol, benzene, and water. The ultraviolet absorption spectrum of each of these extracts showed

no absorption bands other than those of uric acid. Only uric acid was detected by thin—layer

chromatography of these same extracts.

This Standard Reference Material is for "in vitro" diagnostic use only.

This material is for use as a standard in clinical chemistry. A "stock standard" solution containing 1 mg/ml of uric acid may be prepared as follows. Transfer 1.00 g of SRM 913 to a 1000-ml

volumetric flask. Dissolve separately 0.60 g of lithium carbonate (SRM 924) in 150 ml warm

deionized water, filter, and heat filtrate to 60 °C. A slight turbidity at this point may be ignored.

Add the warm lithium carbonate solution to the uric acid (SRM 913) and mix until completely

dissolved. It may be necessary to warm the flask under hot running water during mixing. Cool to room temperature. The solution usually remains slightly turbid. Add 20 ml of 40% formaldehyde.

Dilute to about 500 ml with deionized water, then slowly add with mixing 25 ml of 1 N sulfuric

acid. Dilute to the mark with deionized water, mix well, and place in a glass-stoppered, dark-brown

bottle and store in a refrigerator at 4 °C [ 1,2]

.

A "working" standard solution containing 5 Mg/ml may be prepared by transferring 0.50 ml of

the above "stock" standard solution to a 100-ml volumetric flask and diluting to the mark with

deionized water. Store solution in refrigerator at 4 °C. Prepare fresh weekly.

Similar standard solutions prepared without the use of formaldehyde and sulfuric acid are described by Faulkner and King [3]

.

50
This Standard Reference Material should be stored in a well-closed container at room temperature (30 °C or less). It should not be subjected to heat or direct sunlight during storage. Under

proper storage, experience at NBS indicates this material to be stable for at least 5 years. If the

material purity degrades beyond the limits certified, purchasers will be notified by NBS. It is recommended that material not be used after 5 years from date of purchase.

There are several opinions in the literature regarding the stability of uric acid solutions

[1 ,4,5,6,7,8] . It is recommended that the 1 mg/ml "stock" standard solution be considered stable

for 3 months when stored in a well-stoppered, all-glass, dark-brown bottle at 4 °C. The 5 Mg/ml

"working" standard solution should be prepared fresh weekly and stored in the same manner.

References:

Caraway, W. T., Uric Acid, in Standard Methods of Clinical Chemistry, Vol. 4, David Seligson,

Editor-in-Chief, pp. 239-247, Academic Press, Inc., New York, N. Y. 1963.

Natelson, S., Uric Acid, in Standard Methods of Clinical Chemistry, Vol. 1, Miriam Reiner,

Editor-in-Chief, pp. 5-5-59\ Academic Press, Inc., New York, N. Y., 1953.

Faulkner, W. R., and King, J. W., Renal Function Tests, in Fundamentals of Clinical Chemistry,

N. W. Tietz, Editor, pp. 726-729, W. B. Saunders Company, Philadelphia, Pa. 1970.

Feichtmeir, T., and Wrenn, H., Direct determination of uric acid using uricase. Am. J. Clin.

Path. 25,833-845 (1955).

Dubbs, C, Davis, F. W., and Adams, W. S., Simple microdetermination of uric acid. J. Biol.

Chem. 218,497-504 (1956).

Liddle, L., Seegmiller, J. E., and Laster, L., The enzymetric spectrophotometric method for

determination of uric acid. J. Lab. and Clin. Med. 54, 903-913 (1959).

Henry, R. J., Sobel, C, and Kim, J., A modified carbonate-phosphotungstate method for the

determination of uric acid and comparison with the spectrophotometric uricase method. Am.

J.Clin. Path. 28, 152-160 (1957).

Henry, R. J., Clinical Chemistry, Principles and Technics, pp. 276-287. Hoeber Medical Division, Harper and Row, New York, N. Y. 1967.

This Standard Reference Material has been measured and certified at the Laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B31 1, Chemistry Building

National Bureau of Standards

Washington, D. C. 20234

The date of issuance and certification of this Standard Reference Material was September 24,

1968.

51
U. S. Department of Commerce

Frederick B. Dent

Secretary

N»tion»l BuraaB of Standards

Richard W. Roberta. Director

Rational ££uram xA Standards

©*rttfttat* of ^nalyst*

Standard Reference Material 914

CREATININE

This Standard Reference Material is certified as a chemical of known purity. It is intended

primarily for use in the calibration and standardization of procedures for creatinine determinations

employed in clinical analysis and for routine evaluations of daily working standards used in these

The value of the purity has an estimated inaccuracy of 0.1 percent.

The creatinine used for this Standard Reference Material was obtained from the Pfanstiehl

Laboratories, Inc., of Waukegan, Illinois. Analyses were performed by D. A. Becker, R. F. Brady.

Jr., M. M. Darr, T. E. Gills, R. A. Paulson, W. P. Schmidt, and R. S. Tipson of the Analytical

Chemistry Division.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard Reference Material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

procedures.

Purity

Volatile matter

Chloride . . . . Ash

Insoluble matter

99.8 percent

0.03 percent

0.07 percent

0.003 percent

0.001 percent

Washington, D. C. 20234

September 24, 1968

Revised November 23, 1973

J. Paul Cali, Chief

Office of Standard Reference Materials

(over)

52
The homogeneity of the creatinine was determined by paper, thin—layer, and gas—liquid

chromatography.

Volatile matter was determined by measurement of loss of weight of the creatinine after

heating for 24 hours at 1 10 °C.

Phase— solubility analysis [1] of an oven— dried sample of the Standard Reference Material,

with absolute methanol as the solvent, indicated the purity to be 99.82 weight percent. Phasesolubility analysis of the undried creatinine with 95 percent methanol, and 95 percent ethanol,

indicated purities of 99.81 and 99.76 weight percent, respectively. Potentiometric titration of the

Standard Reference Material required 99.82 percent of the theoretical amount of hydrochloric acid.

The certified value for chloride was obtained by titration with mercuric nitrate of a solution of

the products resulting from an oxygen—flask combustion of the Standard Reference Material

The ultraviolet absorption spectrum of a solution of the creatinine in water showed an extinction coefficient (e max ) of 7140 ± 30 at 234 nm. The measure of uncertainty is the standard

deviation of a single measurement, and should not be considered to be a certified measure of

inaccuracy for the extinction coefficient. Infrared absorption and nuclear magnetic resonance

spectra provided no evidence of impurities.

An emission spectrometric analysis for metallic constituents in the ash from this Standard

Reference Material showed the following present as major constituents: silicon, aluminum, sodium,

titanium, iron, and magnesium. Neutron activation analysis of the bulk Standard Reference Material

indicated the presence of the following approximate concentrations of elements: chlorine, 330

ppm; copper, 0.2 ppm; manganese, 0.07 ppm; sodium, 30 ppm.

This Standard Reference Material is for "in vitro" diagnostic use only.

This material is intended for use as a standard in clinical chemistry. A "stock" standard solution

containing 1 mg/ml of creatinine may be prepared by weighing 0. 100 g of SRM 914 into an 100-ml

volumetric flask. The flask is then filled nearly to the mark with 0.1N hydrochloric acid and

agitated until solution is complete. The flask is then filled to the mark with 0.1N hydrochloric acid.

This solution should be stored in a refrigerator. A "working" standard containing 20 Mg/ml of

creatinine may be prepared by diluting 2.0 ml of the "stock" standard solution to 100 ml with

distilled water in a volumetric flask [2] . This "working" standard solution should be prepared daily.

This Standard Reference Material should be stored in a well-closed container at room temperature (30 °C or less). It should not be subjected to heat or direct sunlight during storage. Refrigerated storage is recommended. Under proper storage, experience at NBS indicates this material to be stable for at least 5 years. If the material degrades beyond the limits certified, purchasers will be

notified by NBS. It is recommended that material not be used after 5 years from the date of

purchase.

The "stock" standard solution containing 1 mg/ml, prepared as described above, is stable

indefinitely when stored in a refrigerator at 4 °C in a well-stoppered, all-glass container. The dilute

"working" standard solution should be prepared daily from the "stock" standard solution [3]

.

53
References:

[1] W. J. Madors, Phase—Solubility Analysis, in Organic Analysis, Vol. II, p. 253, Interscience

Publishers, Inc., New York 1954.

[2] N. W. Tietz, Fundamentals of Clinical Chemistry, pp. 722-726, W. B. Saunders Co., Philadelphia, Pa. 1970.

[3] R. D. Henry, Clinical Chemistry, Principles and Technics, pp. 292-302, Hoeber Medical Division, Harper & Row, New York, N. Y. 1967.

This Standard Reference Material has been measured and certified at the laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D. C. 20234

The date of issuance and certification of this Standard Reference Material was September 24,

1968.

54
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards Richard W. Roberts, Director

^National ££uram af Standards

Certificate of (Analysis

Standard Reference Material 915

Calcium Carbonate

This Standard Reference Material is certified as a chemical of known purity- It is intended

primarily for use in the calibration and standardization of procedures for calcium determinations

employed in clinical analysis and for routine critical evaluation of the daily working standards used

in these procedures.

The sample consists of highly purified calcium carbonate, and chemical assay as well as analysis

for specific impurities indicate that the material may be considered to be essentially pure.

Purity 99.9+ percent

Water 0.01 ± 0.005 percent

Replicate samples taken from a randomly selected region of the undried material were assayed

by a coulometric acidimetric procedure. The results from nine independent determinations, based on expression of the assay as calcium carbonate, indicate a purity of 99.99+ percent with a standard

deviation of 0.003 percent. Samples equilibrated at a relative humiditv of 90 percent and assayed

by this coulometric procedure showed a maximum moisture adsorption of 0.02 percent as compared to samples that were dried for 6 hours at 210 °C. The moisture content, similarly measured, on samples equilibrated at 75 percent relative humidity, was found to be 0.01 percent. The water

content was determined by the Karl Fischer method.

The calcium carbonate used for this Standard Reference Material was obtained from the J. T. Baker Chemical Company, of Phillipsburg, New Jersey. Analyses were performed by C. E. Champion, E. R. Deardorff, G. Marinenko, O. Menis, T. C. Rains, T. A. Rush, W. P. Schmidt, B. F. Scribner, V. C. Stewart, J. K. Taylor, and D. W. Vomhof.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard Reference Material were coordinated through the Office of Standard Reference Materials

by J. L. Hague.

Washington, D. C. 20234 J. Paul Cali, Chief

March 4, 1969 Office of Standard Reference Materials

Revised November 21, 1973

55
The material was examined for compliance with the specifications for reagent grade calcium

carbonate as given in Reagent Chemicals, 4th edition, published by The American Chemical Society.

The material was found to meet or exceed the minimum requirements in every respect. Examination bv thermal gravimetric analysis indicated the loss of a minute proportion of weight below 175

°C (volatile matter) and the composition was stable above this temperature until a temperature of

625 °C, above which decomposition (evolution of C02

) set in.

A semi-quantitative survey for trace contaminants by emission spectroscopy indicated the

presence of less than 0.001 percent of copper, iron, magnesium, manganese and silicon in the

material. By atomic absorption magnesium was evaluated at 1.0, sodium at 0.4, and strontium 2.1 parts per million (ppm); potassium was less than 0.4, lithium less than 0.05, and barium much less than 10 ppm. Neutron activation analysis indicated copper 0.9, manganese 0.6 and sodium 0.5 ppm.

Copper was determined at 1 ppm by spectrophotometry.

This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is for use as a standard in clinical chemistry. It may be used to prepare calcium

standard solutions for either atomic absorption or titrimetric methods of analysis.

Standard stock solutions of calcium for atomic absorption (Reference Method) [jjj Prepare a minimum of three concentrations at 2.00, 2.50, and 3.00 mmol of calcium per liter, with each to contain 140 mmol of sodium chloride and 5.0 mmol of potassium chloride per liter. To each of

three 1 -liter volumetric flasks, add 8.18 g NaCl and 373 mg of KC1. To the first flask (2.00 mmol of

Ca per liter) add 200.2 mg of SRM 915 (dried at 200 °C for 4 hours), to the second flask (2.50

mmol of Ca per liter) add 250.2 mg of SRM 915, and to the third flask (3.00 mmol of Ca per liter)

add 300.3 mg of SRM 915. To each flask add a few milliliters of water and 1 ml of concentrated

HC1. Make sure that all the calcium carbonate is in solution before diluting with water up to the

neck. When at ambient temperature, dilute each flask to the calibrated volume and mix by inverting

the flask 30 times. Pipettings and dilutions of this material should follow the instructions given in reference [ 1 ]

.

Stock solution of calcium for titrimetric procedure : Place 0.250 g of dried SRM 915 into a 1000-ml volumetric flask. Add approximately 9 ml of deionized water and 1 ml concentrated HC1.

Shake until dissolved. Fill to the mark with deionized water and store in a pvrex bottle. This

solution contains 10.0 mg per 100 ml or 5.00 meq. per liter.

This Standard Reference Material should be stored in a well-stoppered bottle (preferably the

original bottle) at room temperature. Calcium carbonate is a stable material. Under proper storage,

experience at NBS indicates this material to be stable for at least 10 years. If the material purity

degrades beyond the limits certified, purchasers will be notified by NBS. It is recommended that the

material not be used after 5 years from the date of purchase.

Solutions prepared from SRM 915, Calcium Carbonate, are stable indefinitely when stored in an glass-stoppered bottle. All such solutions should be clear and display no turbidity.

56
References:

[1] J. P. Cali, G. N. Bowers, Jr., and D.S. Young, Clin. Chem. 19, 1208-1213 (1973).

[2] N. W. Tietz, Fundamentals of Clinical Chemistry, pp. 636-648, W. B. Saunders Co., Philadelphia, Pa., 19105 (1970).

This Standard Reference Material has been measured and certified at the laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

B31 1, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of this Standard Reference Material was March 4, 1969.

57
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Roberta, Director Rational ^uratu of jgttantlartte

(Eerttfttate of (Attaints

Standard Reference Material 916

Bilirubin

This standard reference material is certified as a chemical of known purity. It is intended

primarily for use in the calibration and standardization of procedures for bilirubin determination

employed in clinical analysis and for routine critical evaluation of the daily working standards used

in these procedures.

Purity (bilirubin content) 99.0 percent

Chloroform 0.8 percent

Insoluble (in chloroform) less than 0.01 percent

Ash 0.01 percent

The value of the bilirubin content has a possible estimated inaccuracy of two percent. (See

section on thin-layer chromatography).

The certification of this Standard Reference Material is based on the best current state-of-the-art knowledge. In spite of decades of work on bilirubin, it is still felt that much of its basic chemistry is incomplete.

The material in chloroform (ACS reagent containing ethanol) at 25.0 °C shows at 453 nm an

absorptivity (±1 SD) of 104.6 ± 0.2 liter cm 1 g

1

. In methyl sulfoxide at 25.0 °C, the absorptivity

(±1 SD) of the material at 453 nm is 107.7 ± 0.6 liter cm 1 g1

.

It is recommended that bilirubin and its solutions be handled only under low-intensity incandes- cent light. The bilirubin should be stored under conditions that totally exclude light. Once removed

from the ampoule, the vial should be replaced for storage in an air-tight container and stored at low

temperature. The vial must be allowed to return to room temperature before opening.

The bilirubin used for this standard reference material was obtained from Pfanstiehl Laboratories, Inc., of Waukegan, Illinois. Analyses were performed by R. F. Brady, Jr., R. W. Burke, A.

Cohen, B. Coxon, W. D. Dorko, D. Enagonio, A. J. Fatiadi, D. H. Freeman, J. M. Ives, B. A.

Johnson, E. C. Kuehner, R. A. Paulson, T. C. Rains, R. Schaffer, W. P. Schmidt, J. T. Sterling, J. K.

Taylor, B. F. West, W. J. Zielinski, Jr.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of this standard reference material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

Washington, D. C. 20234 J. Paul Cali, Chief

March 10, 1971 Office of Standard Reference Materials

(over)

58
The standard reference material was prepared from material that was isolated from hog bile and

crystallized as the acid. It was purified further by treatment in chloroform solution with sodium

sulfate according to Fog [1] and retry stallization from chloroform.

Ash was determined on 100-mg samples heated overnight at 250 °C and then for 3 hrs at 650 °C.

Flame photometry and atomic absorption measurements on a solution of the ash obtained from

0.275 g of the material showed, in jug/g (ppm) of metal: <0.05 lithium, 7.3 sodium, 1.6 potassium,

2.1 calcium, and 2.3 magnesium.

Elemental composition found for the material was: C, 67.36; H, 6.24; N, 9.42; CI, 0.73. Required for a bilirubin preparation containing 0.8 percent of chloroform: C, 67.25; H, 6.17; N, 9.50;

CI, 0.71. In these analyses, nitrogen was determined by the Kjeldahl technique; and chlorine was

determined by Carius digestion followed by gravimetric determination as silver chloride. By the

latter method and recalculated as chloroform, the average (±1 SD) of ten 25-mg samples, was 0.83 ± 0.04 percent. The chloroform content was also obtained by heating at 250 °C at 0.5 torr for 4 hrs; the average (± 1 SD) of six 100-mg samples was 0.79 ± 0.02 percent. (Only about one-half or one-tenth of the chloroform was removed at 180 °C and at 110 °C, respectively.) During gradual

heating of the material in a quadrupole mass spectrometer, only ion-fragments characteristic of

chloroform were observed until the sample was heated above 300 °C, whereupon water and carbon

dioxide were detected, and at a somewhat higher temperature, the mass spectrum typical of

bilirubin was obtained. Gas chromatography and nuclear magnetic resonance spectroscopy with the

material dissolved in methyl sulfoxide confirmed the presence of chloroform. Because the chloroform is so firmly retained and homogeneously dispersed, it is recommended that the material be

used as supplied.

Thermogravimetric analysis with the sample heated in a dry nitrogen atmosphere at 5 °C/min

showed the initiation of the loss of a large proportion of sample weight at temperatures between

319 and 323 °C; determined in air, however, comparable weight-loss began between 288 and 292

°C.

For determining the absorptivity of the standard material, absorbances were recorded with a Cary 16 spectrophotometer on solutions using a capped 1 .000 ± 0.001 -cm path-length cuvette in a cell-holder thermostated at 25.0 ± 0.1 °C. Solution preparation and handling were performed under

low intensity, incandescent light; at other times, solutions were totally protected from light. To

preclude any change in concentration of chloroform solutions due to evaporation of the solvent

during solution transfer, nitrogen gas was used to force the solution from the flask through Teflon

tubing into the cuvette and, to effect rinsing of the cuvette, from the latter to an overflow.

Solutions in methyl sulfoxide were transferred to the cuvette by pipet.

For the determination of chloroform-insoluble matter, sample (0.1 g) and solvent (200 ml),

protected from light, were agitated in an ultrasonic bath, heated to 60 °C briefly, and then cooled

and filtered, using pressure, (with 50 ml of the solvent for washing) through a tared 0.4 /jm-porosity

membrane.

Extraction by Bicarbonate. Yellow extracts were obtained by shaking a solution of the standard

reference material (0.010 g) in chloroform (40 ml) with lO-ml volumes of 0.6 molar aqueous

sodium bicarbonate. Their absorption spectra, with maxima in the range 415-430 nm, showed

absorbance values that ranged from 0.035 to 0.030 in successive extracts using 1-cm cells. The

qualitative and quantitative compositions of such extracts were examined using the filtered chloroform solutions containing 0.1

-g quantities of the standard reference material that were prepared in the tests for chloroform insolubles: Extractions twice with 50-ml volumes of the bicarbonate

solution and with water, and neutralization of the combined aqueous extracts followed by extraction into chloroform, yielded pigment (dry weight approximately 0.2 mg) that was shown by its spectrum and specific absorptivity to be typical of bilirubin in chloroform. Thus, bicarbonate

extraction provided no evidence of impurities more acidic than bilirubin.

59
Extraction hy Carbonate. Extraction of a 200-ml chloroform solution containing 0.1 g of standard

with 100-ml volumes of 0.1 molar sodium carbonate reduced the 1-cm absorbance value of the

chloroform layer to approximately 0.22 after the second extraction, and to 0.08 and then 0.01 with

the third and fourth extractions, respectively. On washing with water and then evaporating the

extracted chloroform layer to dryness, residue weights were typically about 0.01 mg. Hence, this extraction process showed a negligible proportion of nonacidic impurities.

Thin-layer Chromatography. An impurity in the standard material may be detected by thin-layer

chromatography with polyamide as the absorbent and 3:1 (v/v) methanol -aqueous ammonium

hydroxide (3.3 percent) as the developer [2]. Thus, 0.05 mg of the material (spotted from a chloroform solution) provides, on development, an elongated, yellow-orange streak preceded (and

usually separate) by a faintly-visible, yellow spot. Under 366-nm irradiation, a pink fluorescence

develops very quickly at the location of this spot. The material responsible for the pink fluorescence

and its precursor have not been characterized. A means for obtaining a reliable estimate of this contribution to overall impurity has not been ascertained, but is under study. Repurification of the

standard material does not affect this behavior.

This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is for use as a standard in clinical chemistry. A standard solution for the development of a calibration curve may be obtained as follows. Weigh out exactly 20.2 mg of SRM 916,

transfer to a 100-ml volumetric flask, and dissolve in 2 ml of 0.1 M sodium carbonate and 1.5 ml of

0.1N sodium hydroxide. The solution should be clear and red in color. Dilute this solution to 100

ml with "acceptable" [3], pooled serum and mix well. Since bilirubin is light sensitive, the flask

should be wrapped in aluminum foil and kept as dark as possible. It is further recommended that

the solution preparation and handling be carried out under low-intensity incandescent light [3,4].

Standard solutions of lower concentration may be prepared by dilution of appropriate aliquots

of the above solution with "acceptable" pooled serum.

Standard Reference Material 916 is supplied in a vial, which is sealed in an ampoule under argon.

The sample must be protected from light. After opening, the material should be kept in the

tightly-closed vial in a desiccator, protected from light by a black plastic bag. Refrigeration at 4 °C

is suggested. Under proper storage, experience at NBS indicates this material to be stable for at least 3 years. If the material degrades beyond the limits certified, purchasers will be notified by NBS. It is recommended that this material not be used after 3 years from the date of purchase.

Solutions of bilirubin, prepared as described above, may be preserved for about a week under

refrigeration at —20 °C.

References

[1] Fog, J., Scand. J. Clin. Lab. Invest., 16,49 (1964).

[2] Petryka, Z. J., and Watson, C. J., J. Chromatog., 37, 76 (1964).

[3] Recommendation on a uniform bilirubin standard, Clin. Chem. 8, 405-407 (1962).

[4] Tietz, N. W., Fundamentals of Clinical Chemistry, W. B. Saunders Co., Philadelphia. Pa., 1970,

pp. 755-762.

This Standard Reference Material has been measured and certified at the laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B31 1, Chemistry Building

National Bureau of Standards

Washington, D. C. 20234

The date of issuance and certification of this Standard Reference Material was March 10, 1971.

60
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Roberts, Director (fltriiixtntt of (Analysis

^National ^mtmx of £tanrfant»

Standard Reference Material 917

D-Glucose (Dextrose)

B. Coxon and R. Schaffer

This standard reference material is certified as a chemical of known purity. It is intended

primarily for use in the calibration and standardization of procedures for glucose determinations

employed in clinical analysis and for routine critical evaluation of the daily working standards used

in these procedures.

Purity 99.9 percent

a-D-Glucopyranose greater than 99.0 percent

0-D-Glucopyranose less than 1.0 percent

Moisture 0.06 percent

Ash 0.002 percent

Insoluble Matter 0.001 to 0.006 percent

Nitrogen less than 0.001 percent

Specific Rotation

[a] p° = +53.2 ° (at equil., c 20.1 in water)

[a] gj6 = +62.8 ° (at equil., c 20.1 in water)

[a] p° = +112.6 ° (initials 10.05 in methyl sulfoxide)

The value for the purity has an estimated inaccuracy of +0.1 percent.

The D -glucose used for this standard reference material was obtained from Pfanstiehl

Laboratories, Inc., of Waukegan, Illinois. Analyses were performed by R. F. Brady, Jr., B. Coxon,

M. M. Darr, T. E. Gills, E. C. Kuehner, R. A. Paulson, T. C. Rains, T. A. Rush, W. P. Schmidt, J. H.

Thomas, and W. L. Zielinski of the Analytical Chemistry Division.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of

this standard reference material were coordinated through the Office of Standard Reference

Materials by T. W. Mears.

Washington, D. C. 20234 J. Paul Cali, Chief

November 18, 1970 Office of Standard Reference Materials

Revised September 20, 1973

61
The only impurities detected in this standard reference material were moisture and traces of

inorganic compounds. Paper, thin-layer, and high-pressure ion-exchange chromatographic techniques revealed no organic impurities.

The proportion of the a -D -glucose anomer was estimated by three methods. The ratio of the

0-anomer to the a-anomer was found to he 0.5:100 by gas-liquid chromatography (gle) after per(trimethylsilyl)ation of the solid standard material for 10 min at 0 °C using N-(trimethylsilyl)imidazole in anhydrous pyridine to minimize possible mutarotation. Use of this gle technique on partly melted standard material showed that the proportion of the 0-anomer increased markedly

during melting. Differential scanning calorimetry of the standard material, contained under nitrogen

in unsealed aluminum pans, showed the ra-D -glucose content to be 99.4 percent. This value

represents only the proportion of anhydrous a-D -glucopyranose present, since the method treats

/3-D -glucose, or hydrates of a-D -glucose that are stable up to the melting point, as impurities.

However, proton magnetic resonance spectroscopy at 90 MHz indicated the ratio of j3-anomer to a-anomer to be 0.9:100. This determination was performed 10 min after dissolution of 100 mg of D -glucose in 0.5 ml of methyl sulfoxide-d6

, by integration of the doublets due to the anomeric

hydroxyl groups.

Optical rotations were obtained by use of an automatic polarimeter and a high-precision

manual polarimeter.

The moisture content reported was determined by the Karl Fischer and near infrared methods.

As only 0.01 to 0.02 percent in weight was lost on drying at 70 °C/l-2 torr for 100 hr, the analyses

reported herein were performed on the undried standard reference material.

The ash content reported was determined by ignition of 20-g samples at 750 °C; the

undissolved residue, on 10-g samples. Turbidimetric assays of solutions of the standard showed the

presence of chloride at 2 ppm and sulfate at 3 ppm. Neutron activation indicated chloride at 4 ppm.

Emission spectrometric analysis of the ash from this standard reference material showed

calcium to be approximately 5 ppm; magnesium and silicon each less than 0.1 ppm; aluminum,

boron and iron each less than 0.05 ppm; and copper, less than 0.01 ppm.

Atomic absorption spectrometry of the standard reference material indicated that it contains

less than 0.5 ppm of magnesium. Flame emission spectrometry indicated the content of calcium to be 1 ±0.5 ppm, and sodium to be 2.9 ppm.

This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is for use as a standard in clinical chemistry. A 1 percent standard solution of

glucose may be prepared by weighing l.OOOg of SRM 917 into an 100-ml volumetric flask. The flask

is then filled nearly to the mark with 0.2 percent benzoic acid solution and agitated until solution is complete. The flask is then filled to the mark with 0.2 percent benzoic acid solution. One ml of this solution contains O.Olg (lOmg) of glucose. The benzoic acid solution should be prepared from ACS

Reagent grade benzoic acid. Appropriate size samples of this solution are analyzed by the exact

procedure used for the submitted specimen of body fluid.

62
To prepare glucose solution of lower concentration the appropriate aliquot is pipetted into a 100-ml volumetric flask and diluted with 0.2 percent benzoic acid solution.

This Standard Reference Material should be stored in a well-closed container at room temperature (30 °C or less). It should not be subjected to heat or direct sunlight during storage. Refrigerated storage is recommended. Under proper storage, experience at NBS indicates this material to be

stable for at least 5 years. If the material purity degrades beyond the limits certified, purchasers will be notified by NBS. It is recommended that material not be used after 5 years from date of

purchase.

The I percent standard glucose solution, prepared as described above, is stable indefinitely when

stored in a refrigerator at 4 °C and in a well-stoppered, all-glass container. The dilute glucose

standard should be prepared daily from the 1 percent stock solution [1,2]

.

All constituted solutions of D-Glucose should be clear and without indications of bacterial

growth of any kind.

References:

[1] R. D. Henry, Clinical Chemistry, Principles and Practice, pp. 625-656, Hoeber Medical

Division, Harper & Row, New York, New York 10016 (1967).

[2] N. W. Tietz, Fundamentals of Clinical Chemistry, pp. 154-163, W. B. Saunders Co.,

Philadelphia, Pa. 19105 (1970).

This Standard Reference Material has been measured and certified at the Laboratories

of the National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be

addressed to

:

Office of Standard Reference Materials

Room B3 11, Chemistry Building

National Bureau of Standards

Washington, D. C. 20234

The date of issuance and certification of this Standard Reference Material was November 18, 1970.

63
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Roberta, Director

This standard reference material is certified as a chemical of known purity. It is intended

primarily for use in the calibration and standardization of procedures employed in the determination of potassium and chloride ions in clinical analyses. The sample consists of highly purified

potassium chloride. Chemical assay as well as analyses for specific impurities indicate that the

material may be considered essentially pure, except for moisture due to occlusion.

Purity 99.9 ± 0.0 percent

The above value for the purity of the material is based on a sample dried over magnesium

perchlorate for 24 hours. Potassium chloride is hygroscopic when the relative humidity at room

temperature exceeds 75 percent, but can be dried to the original weight by desiccation over freshly

exposed ^2^5 or Mg(C10 4 ) 2 for 24 hours. The material should be stored with such a desiccant. The

potassium was determined by a combination of gravimetric and isotope dilution analyses. More than

99 percent of the potassium was precipitated, filtered, and weighed as potassium perchlorate. The

weight of potassium perchlorate was corrected for rubidium perchlorate. The soluble potassium was

determined by isotope dilution mass spectrometry. Total potassium was the sum of the potassium

from the potassium perchlorate and the potassium from the filtrate. The chloride was determined

by a coulometric argentimetric procedure.

Based on 12 independent measurements for each ion, the sample was considered homogeneous.

Material dried at 500 °C for 4 hours in a platinum or Vycor crucible (Pyrex is unsatisfactory) was

assayed at 99.98 ± 0.01 percent. The loss of moisture by this procedure was about 0.07 percent.

The potassium chloride used for this standard reference material was obtained from the J. T. Baker Chemical Company, of Phillipsburg, New Jersey. Analyses were performed by G. Marinenko,

T. J. Murphy, T. C. Rains, T. A. Rush, W. P. Schmidt, and V. C. Stewart.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of W. R. Shields.

The technical and support aspects concerning the preparation, certification, and issuance of this standard reference material were coordinated through the Office of Standard Reference Materials

by J. L. Hague.

Washington, D. C. 20234 J. Paul Cali, Chief

January 22, 1971 Office of Standard Reference Materials

Revised November 23, 1973

Potassium Chloride

(Clinical Standard)

(over)

64
This material was examined for compliance with the specifications for reagent grade potassium

chloride as given in Reagent Chemicals, 4th edition, published by the American Chemical Society.

The material met or exceeded the minimum requirements in every respect.

A semi-quantitative survey for trace contaminants by emission spectroscopy indicated the

presence of less than 0.001 percent aluminum, copper, iron, and magnesium. A value of 0.24 parts

per million (ppm) of magnesium was obtained by atomic absorption spectrometry. Flame emission

spectrometry indicated the presence of the following elements: rubidium, 27 ppm; sodium, 9 ppm;

lithium, 0.6 ppm; and cesium and calcium, less than 2 ppm.

This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is intended for use as a standard for potassium and, to a lesser degree, for chloride

determination in clinical chemistry.

Potassium is most frequently determined by flame emission photometry. The operative details

of this methodology vary from instrument to instrument and are discussed at length in their

respective operating manuals. A standard solution of potassium chloride (10 mmol potassium per

liter) may be prepared as follows: transfer 0.746 g of SRM 918 that has been dried to constant

weight quantitatively to a 1-liter volumetric flask, dilute to volume with water, and make the

solution uniform by inverting the flask at least 30 times. The concentrations required for analysis

may be prepared by accurate dilution of this standard with deionized water.

A standard solution of chloride containing 100 mmol per liter may be prepared by transferring

quantitatively 7.46 g of SRM 918 to a 1-liter volumetric flask and adding 3 ml of concentrated

nitric acid (ACS Reagent Grade) and 100 ml of deionized water. After all the salt is dissolved, dilute to volume with deionized water. It should be noted that a chloride standard solution prepared from

sodium chloride contains the respective ions in a ratio more nearly that of normal serum than a solution prepared from potassium chloride.

This Standard Reference Material should be stored in the well-closed original container under

normal laboratory conditions. It is recommended that weighing and other manipulations of the

solid SRM not be made when the relative humidity exceeds 75 percent.

The solutions of SRM 918 are stable indefinitely when stored in a well-stoppered, all-glass

container. All such solutions should be clear and display no turbidity.

References:

[1] P. M. Hald and W. B. Mason, "Sodium and potassium by flame photometry", in Standard

Methods of Clinical Chemistry, Vol. 2, David Seligson, editor-in-chief, pp. 165-185, Academic

Press, Inc., New York, (1958).

[2] N. W. Tietz, Fundamentals of Clinical Chemistry, pp. 621-625, W. B. Saunders Company,

Philadelphia, Pa. (1970).

This Standard Reference Material has been measured and certified at the laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of this Standard Reference Material was Januarv 22,

1971.

65
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Roberta, Director ^National ^mtnn of j^tandartfe

Ccrttfttate of .Analyst*

Standard Reference Material 919

Sodium Chloride

(Clinical Standard)

This Standard Reference Material is certified as a chemical of known purity. It is intended

primarily for use in the calibration and standardization of procedures employed in the determination of sodium and chloride ions in clinical analyses. The sample consists of highly purified sodium

chloride. Chemical assay as well as analyses for specific impurities indicate that the material may be

considered essentially pure, except for occluded moisture.

Purity . 99.9 ± 0.0 percent

The above value for the purity of the material is based on a sample dried over magnesium

perchlorate for 24 hours. At room temperature sodium chloride is hygroscopic above 60 percent

relative humidity. The sorbed water can be removed, however, by desiccation over freshly exposed

P2O5 or Mg(C104)2 for 24 hours. Chloride was determined using the coulometric method of

Marinenko and Taylor [J. Res. NBS, 67A, 31(1963)].

Based on 8 independent measurements of chloride content, the sample is considered homogeneous.

When the material is crushed and dried at 200 °C for 18 hours, the loss of moisture is about

0.08 percent. Coulometric determinations of chloride on the dried material indicate 99.995 ± 0.004

percent purity.

The sodium chloride used for this Standard Reference Material was obtained from the J. T. Baker Chemical Company, of Phillipsburg, New Jersey. Analyses were performed by G. Marinenko,

J. R. Baldwin, M. Darr, and T. C. Rains.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of R. A. Durst.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard Reference Material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

Washington, D. C. 20234 J. Paul Cali, Chief

August 6, 1973 Office of Standard Reference Materials

Revised November 23, 1973

(over)

66
This materia] was examined for compliance with the specifications for reagent grade sodium

chloride as given in Reagent Chemicals, 4th edition, published by the American Chemical Society.

The material meets or exceeds the minimum requirements in every respect.

Sodium was assayed using a gravimetric procedure in which the sodium chloride was converted

to sodium sulfate. Approximately 250 mg of sodium chloride (dried at 500 °C for 4 hours in a platinum crucible) was dissolved in ultrapure sulfuric acid solution (1:1) and evaporated to dryness.

Ammonium carbonate was added and the crucible slowly heated to 600 °C, then 900 °. This

treatment was repeated until the weight of sodium sulfate remained constant. Based on 6 determinations, the sodium assay is 39.

3

2 weight percent or 99.

9

6 percent of the amount computed for

perfectly pure, stoichiometric NaCl.

A semiquantitative survey for trace elements by emission spectroscopy indicated less than 10

Mg/g calcium, copper, iron, and magnesium. A value of less than 3 Mg/g magnesium was obtained by

atomic absorption spectrometry. Flame emission spectrometry indicated the presence of the following elements: potassium, 11 /Jg/g; calcium and cesium, less than 2 Mg/g; and rubidium and lithium

less than 0.5 Mg/g.

This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is intended for use as a standard for the determination of sodium and chloride

ions in clinical chemistry.

Sodium is most frequently determined by flame emission photometry. The operative details of

this methodology vary from instrument to instrument and are discussed at length in their respective

operating manuals. A standard solution of 100 mmol of sodium chloride per liter (suitable for both

sodium and chloride determinations) may be prepared by placing 5.85 g of SRM 919 (dried at 110

°C) in a 1 -liter volumetric flask and adding 3 ml of concentrated nitric acid (ACS Reagent Grade)

and 100 ml of deionized water. After the NaCl is dissolved, dilute to the mark with deionized water. The concentration required for analysis may be prepared by accurate dilutions with distilled water.

This Standard Reference Material should be stored in the well-closed original, bottle under

normal laboratory conditions. It is recommended that weighing and other manipulations not be

made when the relative humidity exceeds 60 percent.

Solutions of SRM 919 are stable indefinitely when stored in a well-stoppered, all-glass container. All such solutions should be clear and display no turbidity.

References:

[1] IN. W. Tietz, Fundamentals of Clinical Chemistry, pp. 616-618; 621-625, W. B. Saunders Co.,

Philadelphia, Pa. (1970).

[2] R. D. Henry, Clinical Chemistry, Principles and Practice, pp. 345-350: 402-409, Hoeber Medical

Division, Harper & Row, New York, N. Y. (1967).

This Standard Reference Material has been measured and certified at the laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D. C. 20234

The date of issuance and certification of this Standard Reference Material was August 6, 1973.

67
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Roberta, Director

B. Coxon and R. Schaffer

This Standard Reference Material is certified as a chemical of known purity. It is intended

primarily for use in the calibration and standardization of procedures for triglycerides determinations employed in clinical analysis and for routine critical evaluation of the daily working

standards used in these procedures.

The value for the purity has an estimated inaccuracy of 0.1 percent.

The D-mannitol used for this Standard Reference Material was obtained from Pfanstiehl

Laboratories, Inc., of Waukegan, Illinois. Analyses were performed by R. F. Brady, Jr., B. Coxon, B. A. Johnson, W. H. McCurdy, and W. P. Schmidt of the NBS Analytical Chemistry Division.

The overall direction and coordination of technical measurements leading to the certification was under the chairmanship of R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of this

Standard Reference Material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

D-Mannitol . D-Glucitol . . Total Alditol. 99.8 percent

. . 0.1 percent

. 99.9 percent

Loss on drying <0.02 percent

Ash

Insoluble matter

<0.001 percent

<0.001 percent

Washington, D. C. 20234

January 17, 1972

Revised November 23, 1973

J. Paul Cali, Chief

Office of Standard Reference Materials

(over)

68
The homogeneity of this Standard Reference Material was monitored by differential scanning

calorimetry of 20 samples taken at random from the bulk material, and by polarimetry, gas-liquid

chromatography, and thin-layer chromatography. Elemental microanalysis (±2 SD) showed carbon

39.51 ± 0.10 and hydrogen 7.86 ± 0.12: the calculated values are 39.56 and 7.75 percent,

respectively. The Standard Reference Material melted at 167.0—168.0 °C (corr.) when heated in an open capillary at 0.5 °C min" 1

.

The content of D-glucitol in the material was determined by gas-liquid chromatography of

hexakis-o-(trifluoroacetyl) derivatives on a 10-ft. column of Gas Chrom Q (100-120 mesh) coated

with 3 percent of GE-XE-60 liquid phase, using a flame-ionization detector. The derivatives were

prepared by treating 200 mg of the D-mannitol with 2 ml of trifluoroacetic anhydride and 10 mg of

sodium trifluoroacetate in 2 ml of nitromethane for 2 hours at 25-30 °C. The solution resulting was

diluted to 5.0 ml with nitromethane, and 2-ml aliquots were injected into the gas chromatograph

(inlet temperature, 135 °C; column, 145 °C; detector, 150 °).

The purity of the Standard Reference Material, as determined by differential scanning

calorimetry, is 99.9 mole percent, and by phase solubility analysis, 99.8 weight percent. For

differential scanning calorimetry, the D-mannitol (~0.5 mg) was heated from 380 to 436 K at 80

Kmin"1 and then from 436 to 442 K at 0.625 Kmin" 1. Phase solubility analysis was conducted by

equilibrating the material with either ethanol-water (1:1 v/v), or methanol-water (1:1 v/v) at 25 °C

for six days.

No impurities were revealed by paper and thin-layer chromatography, infrared spectroscopy

(KC1 pellet), ultraviolet spectrophotometry (20-percent solution of the material in water), or by

proton and carbon- 13 magnetic resonance spectroscopy.

The proton magnetic resonance spectrum obtained at 90 MHz by accumulating 324 frequency

sweeps of a solution of 0.1 g of the material in 0.5 ml of methyl sulfoxide-c?6 showed, as expected

for D-mannitol, only a complex multiplet and a doublet at 4.4 and 4.2 ppm, respectively, from

tetramethylsilane, due to six hydroxyl protons, and a complex multiplet at 3.5 ppm due to eight

CH protons.

The proton-decoupled carbon-13 magnetic resonance spectrum, accumulated at 22.6 MHz from

1024 scans of a saturated solution of the material in water-hexafluoroacetone sesquihydrate (5:1

v/v), with heteronuclear, field-frequency stabilization on fluorine, showed only three singlets, at 122, 123, and 129 ppm from external, 13 C-enriched carbon disulfide, owing to the two-fold axis of

symmetry of D-mannitol.

In the absence of proton decoupling, 5650 scans of a similar solution gave a carbon-13 nmr

spectrum that showed only two overlapping doublets (^13

c H 146 and 141 Hz), each overlapped by

a triplet (7l 3

C H 142 Hz).

Optical rotations were measured by means of an automatic polarimeter and a high-precision,

manual polarimeter, by using solutions of the material either in water, or in aqueous 4.7 percent

ammonium molybdate solution (20.0 ml) diluted to 25.0 ml with 0.5 M sulfuric acid at 20 °C.

[<*] 2D

°= 139.0° (c 1.6 in acidified 3.8 percent ammonium molybdate solution)

["]

2D

° = -0.3° (c 16.0 in water)

On being heated at 70 °C under vacuum for 24 h, 7-g samples of the Standard Reference

Material lost 0.001 to 0.002 percent of their weight; however, at 110 °C and 30 torr, constant

weight was not reached during 80 h, at which time, 50-g samples of the material had decreased in weight by 0.02 percent, corresponding mainly to sublimation of the samples.

The residue insoluble in water and the ash content of the Standard Reference Material were each

determined on 25-g samples.

69
This Standard Reference Material is intended for "in vitro" diagnostic use.

This material is for use as a standard in the determination of triglycerides in clinical chemistry.

Since mannilol solutions require no preliminary handling prior to the automated part of the analysis

they are useful in checking automated systems. A stock solution may be prepared hy transfer of

182.2 mg of SRM 920 to a 1-liter volumetric flask, dissolving it in 0.2 N sulfuric acid and diluting to

the mark with 0.2 N sulfuric acid. This solution contains 1 jumol/ml 0 f mannitol. Working solutions

of 0.050, 0.100, and 0.150 jumol/ml may be prepared by dilution of appropriate aliquots with 0.2 N

sulfuric acid [ 1 ,2]

.

This Standard Reference Material should be stored in a well-closed container at room

temperature (30 °C or less). It should not be subjected to heat or direct sunlight during storage.

Under proper storage, experience at NBS indicates this material to be stable for at least 5 years. If the material degrades beyond the limits certified, purchasers will be notified by NBS. It is recommended that material not be used after 5 years from date of purchase.

The stock standard solution (1 ^mol/ml) and the working solutions should be stored in a glass-stoppered, brown bottle at 4 °C. Under such conditions these standards should be stable for 6

months.

All constituted solutions of D-mannitol should be clear and display no turbidity.

References:

(1] Kanter, S. L., Mannitol as a primary standard in the determinations of triglycerides. Clin. Chim.

Acta 16, 177-178(1967).

[2| Communication from Lipids Laboratory, Center for Disease Control, Atlanta, Ga., January 8,

1974.

This Standard Reference Material has been measured and certified at the laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. AU\inquiries should be addressed to:

Office of Standard Reference Materials

Room B311 , Chemistry Building

National Bureau of Standards

Washington, D. C. 20234

The date of issuance and certification of this Standard Reference Material was Janaury 17, 1972.

70
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Roberta, Director

Standard Reference Material 921

Cortisol (Hydrocortisone)

B. Coxon and R. Schaffer

This Standard Reference Material is certified as a chemical of known purity. It is intended

primarily for use in the calibration and standardization of procedures for Cortisol determinations

employed in clinical analysis and for routine critical evaluation of the daily working standards used

The Cortisol assay has an estimated inaccuracy of 0.2 percent.

The Cortisol used for this Standard Reference Material was obtained from the Upjohn Company, Kalamazoo, Michigan. Analyses were performed by R. F. Brady, Jr., A. Cohen, B. Coxon, M.

Darr, W. D. Dorko, D. P. Enagonio, T. E. Gills, E. E. Hughes, W. P. Schmidt, and S. A. Wicks of the

Analytical Chemistry Division.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard Reference Material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

in these procedures.

Constituent Percent

Cortisol

21-Dehydrocortisol

21-O-Acetylcortisol

21-Dehydrocortisone

Cortisone

Total Steroids . . . Ash

Insoluble matter . . Loss on drying . . .

98.9

0.6

0.2

0.1

0.1

99.9

0.002

0.001

0.08

Washington, D. C. 20234

February 15, 1973

Revised December 16, 1973

J. Paul Cali, Chief

Office of Standard Reference Materials

(over)

71
Identification and quantitation of the four steroid impurities were accomplished by Fouriertransform proton-magnetic-resonance (pmr) spectroscopy and thin-layer chromatography (tic) per- formed on fractions from the liquid chromatography of 100 mg of the material in ethanol on a column (91 x 0.8 cm) of poly(vinylpyridine) crosslinked with 8 percent of divinylbenzene. Fractions were eluted with ethanol at a pressure of 4.7 kg-cm" 2

. Tic of aliquots of the fractions was

performed on silica gel GF254 using 9:1 (v/v) chloroform-methanol. Equivalent sensitivity of detection was obtained by fluorescence quenching and by spraying with aqueous 20-percent sulfuric acid

and heating at 120 °C. All the steroid impurities, except 21-dehydrocortisone, showed similar

sensitivity. 4-Androsten-l l0-ol-3,17-dione was found in liquid chromatography fractions, but could

not be demonstrated directly by tic of up to 1 mg of the bulk material. Because this compound was

readily resolved from mixtures prepared with it and the bulk material and detected in proportion to amounts used for reference, the compound was adjudged an artifact produced during liquid chromatography. On the other hand, the major impurity, 21-dehydrocortisol, did not arise by the known

copper-catalyzed oxidation of Cortisol, as shown by its unaltered proportion by tic of the bulk

material even after EDTA-treatment of the system to remove copper.

The quantitative proportion of each steroid present in the sample was estimated from the dry

weight ( W) of the residue of each liquid chromatographic fraction and the measured intensity of the

Fourier-transform generated methyl signals characteristic for each steroid, using the expression:

Whn Mn m„ Mn h,M, + h2 M2 ...+ hm Mm

where mn and Mn are the number of moles present and the molecular weight, respectively of the

nth component in a mixture of m components, hn

is the methyl signal intensity of the nth component, and .--h m

are the corresponding intensities of components l...m, obtained by meas- urement of the methyl peaks above the methylene envelope of the steroids.

For proof of homogeneity, nine samples were withdrawn from the bulk Standard Reference

Material according to a statistical plan. They were analyzed in a commercial carbonhydrogen-nitrogen microanalyzcr and were found to be homogeneous with respect to carbon and

hydrogen content within the limits of precision of the method. Solutions of the samples in 95

percent ethanol at 25 °C showed an absorbance maximum at 242 nm with a molar extinction

coefficient of 16.1 x 103 litercm" 1 .mol" 1

.

Elemental maeroanalvsis of the material showed carbon 69.49 ± 0.10 percent (2 SD of the

mean); and hydrogen 8.39 ± 0.05 percent (2 SD of the mean); the calculated values for Cortisol are 69.58 percent and 8.34 percent, respectively.

The Standard Reference Material melted at 219.0-220.5 °C (corrected) when heated in an open

capillary tube at 0.5 °Cmin"'. The resulting pale yellow melt did not solidify on cooling. After

sealing in a capillary tube under vacuum, the material melted at 220.5-221.5 °C without yellowing,

but did not resolidify.

The-rmogravi metric analysis of samples heated under dry nitrogen at 2 °C-min_1 showed the

initiation of loss of a large proportion of sample weight at 221 °C (uncorrected). However, for

samples heated in air, loss of weight began at 204 °C. The attempted application of differential

scanning ealorimetrv to samples heated under nitrogen gave thermograms that were very dependent on the rale and time of heating, and that were not reproducible.

72
The mass spectrum of the Standard Reference Material obtained by electron induced ionization •

at 70eV and a probe temperature of 220 °C showed strong ion currents at m/e 362 [M '], 344

[M-18(H 2 0)], 332 |M-30(CH 2 O)], 303 [M-59(COCH2 OH)] , 302 [M-60(CH 2 =C=O and

H2 0)1, 285 [M-59-18], 42 [CH2 =C=0] , and 31 [CH2 =0-H]+

. The peaks at m/e 302 and 163

correspond to the molecular ion and key fragment, respectively, of the thermal degradation product

of Cortisol, namely 4-Androsten-l l/3-ol-3,l 7-dione.

Optical rotations of solutions of the Standard Reference Material in ethanol (c 1. 00) were measured at 20 °C by means of automatic and high-precision, manual polarimeters and are as follows:

(±2 SD of the mean)

X (nm) degrees radians

589 168.9±0.1 2.948±0.002

578 177.3±0.1 3.094±0.002

546 205.6±0.1 3.588±0.002

436 387.9+0.4 6.770±0.007

365 571 .7±0.6 9.978±0.010

Insoluble matter was determined by filtration of solutions of the Standard Reference Material

(1.8-2.0 g) in methyl sulfoxide (9-20 ml) through Millipore filters (1.5 Mm).

The loss of weight on drying was determined after heating three samples (2.8 g, each) of the

material at 110 °C and 0.1 torr for 24 hours. No further weight loss occurred during heating of the

samples for an additional 48 hours.

Ash was determined by heating of samples (10 g) of the Standard Reference Material to 700 °C.

Spectrometric analysis of the ash indicated calcium as a major constituent, and sodium, magnesium,

and silicon as minor constituents.

Destructive neutron activation analysis using SRM 1577, Bovine Liver, as a standard indicated

that the Cortisol Standard Reference Material contains 0.035±0.005 ppm (±2 SD of the mean) of

copper.

This Standard Reference Material is for "in vitro" diagnostic use only.

A standard solution containing 5 /ug per ml of Cortisol may be prepared as follows. Transfer 50

mg of SRM 921 to a 50-mI volumetric flask and add 35 ml of absolute ethanol. When the Cortisol is completely dissolved, dilute to the mark with absolute ethanol. Dilute 1 ml of this ethanol solution

to 200 ml with distilled water [ 1 ,2]

.

Working standard solution may be made by appropriate dilution of aliquots of the 5 /ug per ml

solution with distilled water.

This Standard Reference Material should be stored in a well-closed container at room temperature (30 °G or less). It should not be subjected lo heat or direct sunlight during storage. Refrigerated storage is recommended. Under proper storage, experience at NBS indicates purified Cortisol to be stable for at least 5 years. If the material purity degrades beyond the limits certified,

purchasers will be notified by NBS. It is recommended that material not be used after 5 years from

date of purchase.

73
The solution of 1 mg/ml of Cortisol in ethanol as prepared above should be stored in a well- stoppered, all-glass container and kept in a refrigerator at 4 °C. The aqueous solution of 5jUg per

ml Cortisol should also be stored in a well-stoppered, all-glass container at 4°C. Under these conditions both solutions should be stable for six months. The more dilute "working" standard solutions

should be prepared daily.

All constituted solutions of Cortisol should be clear and display no turbidity.

References:

11] R. E. Peterson, "Hydrocortisone in plasma", in Standard Methods of Clinical Chemistry, Vol.

3, David Seligson, Editor-in-Chief, pp. 160-166, Academic Press, Inc., New York, N. Y. (1961).

[2] N. W. Tietz, Fundamentals of Clinical Chemistry, pp. 509-512. W. B. Saunders Company,

Philadelphia, Pa., (1970).

This Standard Reference Material has been measured and certified at the laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D. C. 20234

The date of issuance and certification of this Standard Reference Material was February 15,

1973.

74
U.S. Department of Commerce

Elliot L. Richardson,

Secretary

National Bureau of Standards

Ernest Ambler, Acting Director Rational ^Bureau of j&andartte

(Eerttftcate

Standard Reference Materials

Tris(hydroxymethyl)aminomethane (922)

Tris(hydroxymethyl)aminomethane hydrochloride (923)

B. R. Staples

These Standard Reference Materials are intended for use in preparing secondary standard pH buffer solutions

in the physiological range. Such buffers are used in the clinical laboratory in cases where phosphate buffers would cause undesirable side reactionsor do not adequately approximate the required variation of pH with

temperature. Coulometric assay indicates the tris(hydroxymethyl)aminomethane to be 99.99 ± 0.02 mole

percent after drying in a vacuum oven at 70 °C for 24 hours. Coulometric assay of the tris(hydroxymethyf)-

aminomethane hydrochloride as received was 99.69 ± 0.05 mole percent.

The pH(S) values listed below correspond to log(l/aH), where aH is a conventional activity of the hydrogen

(hydronium) ion referred to the standard state on the scale of molality. The values were derived from the emf of

cells without liquid junction by the method of calculation described by Bates [1]. The uncertainty of the assigned

values of pH(S) is estimated not to exceed ±0.005 unit. The values listed below apply only to the material herein

certified.

The solution recommended for the calibration of pH equipment is 0.01667 molal with respect to tris(hydroxymethyl)aminomethane and 0.0500 molal with respect to tris(hydroxymethyl)aminomethane hydrochloride.

The pH(S) of this solution as a function of temperature is as follows:

°C pH(S) °C pH(S) °C pH(S)

0 8.471 20 7.840 37 7.382

5 8.303 25 7.699 40 7.307

10 8.142 30 7.563 45 7.186

15 7.988 35 7.433 50 7.070

The name "tris(hydroxymethyl)aminomethane" is used preferentially in this certificate since it is the name

commonly used in clinical laboratories. Under the system of nomenclature recommended by the International

Union of Pure and Applied Chemistry this material is named 2-amino-2-(hydroxymethyl)-I,3-propanediol. It

is also known by several trivial and proprietary names, e.g., "tris," "THAM," "trizma," "tromethamine,"

"tromethane," etc. However, the certified values given herein apply only to the material supplied as an NBS-SRM.

The tris(hydroxymethyl)aminomethane and tris(hydroxymethyl)aminomethane hydrochloride were obtained

from the Sigma Chemical Company of St. Louis, Missouri.

The overall direction and coordination of technical measurements leading to the certification wus performed

under the chairmanship of R. A. Durst.

The technical and support aspects involved in the preparation, certification, and issuance of these Standard

Reference Materials were coordinated through the Office of Standard Reference Materials by T. W. Mears.

Washington, D.C. 20234 J. Paul Cali, Chief

June 23, 1971 Office of Standard Reference Materials

Revised December 13, 1973

Revised August 20, 1976

(over)

75
These Standard Reference Materials (SRM's) are intended for "in vitro" diagnostic use only.

This material is for use in preparing standard buffer solutions for use in clinical chemistry. A buffer solution

having the pH values certified on the face of this certificate is 0.0 1 667 molal with respect to tris(hydroxymethyl)-

aminomethane and 0.0500 molal with respect to tris(hydroxymethyl)aminomethane hydrochloride. The pre- paration of this solution is described in the following paragraph.

Transfer 7.800 g of tris(hydroxymethyl)aminomethane hydrochloride (SRM 923) and 1 .999 g of tris(hydroxymethyl)aminomethane (SRM 922) to a 1-litre volumetric flask. (The figures given are weights in air; bouyancy

corrections are not required.) Dissolve and fill to the mark with distilled water at 25 °C. The distilled water should not contain dissolved carbon dioxide and should have a conductivity no greater than 2 X 10" S-cm"

1 (2X 10" ohm ' cm '). Carbon dioxide-free water can be prepared by boiling a good grade of distilled water for

10 rhinutcs and guarding it with a tube of carbon dioxide absorbant. The certified pH(S) values apply for materials as received. No particular drying procedures are necessary. The tris(hydroxymethyl)aminomethane

should not be heated above 80 °C and as a precaution the tris(hydroxymethy!)aminomethane hydrochloride

should not be exposed to temperatures above 40 °C.

CAUTION: Reference electrodes containing linen-fiber or dialysis-membrane junctions should not be used

with this buffer. Such junctions produce large liquid-junction potentials, drift, and long equilibrium times. Reference electrodes with other types of liquid junctions may also exhibit operational pH values which differ from the assigned pH(S) by up to 0.05 unit. For this reason, solutions of this buffer are not recommended as prim'ary standards of pH except in cases where a liquid junction is not involved. This buffer is useful, however,

as a secondary standard in cases where the phosphate buffers are not satisfactory, as noted above.

Standard Reference Material 922 should be stored in a well-closed container at room temperature. Exposure to high temperatures (above 50 °C) and direct sunlight should be avoided. Experience has shown this compound

to be stable in storage for at least I2years[2]. If the material degrades such that the certified values are changed,

the users will be notified by NBS. It is recommended that this material not be used after 5 years from the date of

purchase.

Standard Reference Material 923 should be stored in a well-closed container at room temperature, preferably in a desiccator. Exposure to high temperatures (above 40 °C) and direct sunlight should be avoided. SRM 923,

tris(hydroxymethyl)aminomethane hydrochloride, is quite hygroscopic even at relative humidities of 30 to 50

percent [3]. Experience at NBS has indicated that, properly stored, this material is stable for at least 5 years. Weighing and other manipulations of SR M 923 should be avoided under conditions when the relative humidity

exceeds 50 percent. If the material degrades such that the certified values are changed, the users will be notified by NBS. It is recommended that this material not be used after 5 years from the date of purchase.

This buffer solution is sensitive to contamination by carbon dioxide [4]. If the solution is to maintain the assigned pH(S) for a few weeks the exclusion of carbon dioxide is essential. The solution should be replaced

after a few weeks, or sooner if mold or sediment appear, or if it is repeatedly exposed to air containing carbon

dioxide.

References:

[1] R. G. Bates, Revised Standard Values for pH Measurements From 0 to 95 °C, J. Research NBS 66A, 179

(1962).

[2] J. A. Riddick, Amine Buffers as Acidimetric Standards, Ann. N Y. Acad. Sci. 92, 357 (1961).

[3] Sigma Tentative Technical Bulletin No. 106 B, Sigma Chemical Company, St. Louis, Mo., revised 1967.

[4] R. G. Bates and H. B. Hetzer, Absorption of Carbon Dioxide by Solutions of 2-amino-2-(hydroxymethyl)-l,3-propanedioI, Anal. Chem. 33, 1285 (1961).

These Standard Reference Materials have been measured and certified at the laboratories of the National

Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standards Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D. C. 20234

The date of issuance and certification of these Standard Reference Materials was June 23, 1971.

76
S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Robe.ta, Director ^athnal ^Bureau of jiltantlartte

(tterttfttaie of ^mlyti*

Standard Reference Material 924

Lithium Carbonate

This Standard Reference Material is certified as a chemical of known purity. It is intended

primarily for use in calibration and standardization of procedures employed in clinical analysis and

for the routine critical evaluation of daily working standards used in these procedures.

The purity shown is based on the determination of the carbonate ion by coulometric aci- dimetry. The molecular weight for lithium carbonate employed in the calculations is 73.9486. This

value is based on a mass-spectrometrically determined value of 6.9696 for the atomic weight of

lithium in this sample. The uncertainty shown represents the 95-percent confidence interval of the mean based on 16 determinations. The assay in excess of 100 percent may be due to anion

impurities of lower molecular weight than the carbonate ion, e.g., hydroxide.

This Standard Reference Material is of limited certification because no actual determination of

lithium content was made. The certification is based on the analysis of the carbonate anion and the

proven absence (or presence in trace quantities) of metallic cations.

The lithium carbonate used for this Standard Reference Material was obtained from the J. T. Baker Chemical Company of Phillipsburg, New Jersey. Analyses were performed by G. Marinenko,

M. Darr, E. L. Garner, T. C. Rains, and T. A. Rush.

The overall direction and coordination of technical measurements leading to certification were

under the chairmanship of R. A. Durst.

The technical and support aspects concerning preparation, certification, and issuance of this Standard Reference Material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

Purity 100.05 ± 0.02 Percent

Washington, D. C. 20234

February 23, 1972

Revised November 23, 1973

J. Paul Cali, Chief

Office of Standard Reference Materials

(over)

77
The lithium carbonate meets or exceeds the specifications for reagent grade lithium carbonate

as given in Reagent Chemicals, 4th edition, published by the American Chemical Society. A semiquantitative survey for trace contaminants by emission spectroscopy showed no significant metallic

impurities. Atomic absorption and flame emission spectrometry showed neither alkali metal nor

alkaline-earth impurities in excess of 1 ppm except calcium (4 ppm).

This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is intended for use as a standard for determination of lithium in clinical chemistry. For best results using either atomic absorption spectroscopy or flame emission photometry it

is necessary that lithium be determined against a background of sodium and potassium.

A "standard" solution containing 1.00 mmol of lithium per liter may be prepared as follows.

Dry SRM 924 for 4 hours at 200 °C, then cool to room temperature in a desiccator. Dissolve 73.91

mg of SRM 924 in 50 ml of deionized water and 20 ml of 0.1N HC1 (ACS Reagent Grade). Dilute to the mark with deionized water and mix well in a 2-liter class-A volumetric flask.

A "blank" solution containing 140 mmol of sodium per liter and 5 mmol of potassium per liter may be prepared as follows: Dissolve 8.18 g of sodium chloride (SRM 919) and 0.373 g of

potassium chloride (SRM 918) in deionized water. Bring to the mark of a 1-liter flask with de- ionized water and mix well.

Working standards containing 0.10 or 0.1*0 mmol of lithium, 14 mmol of sodium and 0.5 mmol

of potassium per liter may be prepared as follows. To each of two 100-ml volumetric flasks add 10

ml of "blank solution". Add exactly 10.00 ml of "standard solution" to one flask and exactly

20.00 ml of "standard solution" to the second flask using class-A volumetric pipettes. Dilute each

flask to the mark with deionized water and shake well.

This Standard Reference Material should be stored in the well-closed original bottle under

normal laboratory conditions.

The solutions of SRM 924 are stable indefinitely when stored in a well-stoppered, all-glass

container. All such solutions should be clear and display no turbidity.

References:

[1] J. Pybus and G. N. Bowers, Jr., Serum lithium determination by atomic absorption spec- troscopy, in Standard Methods of Clinical Chemistry, Vol. 6, R. P. McDonald, editor-in-chief,

pp 189-192, Academic Press, Inc., New York, N. Y. (1970).

[2] A. L. Levy and E. M. Katz, A comparison of serum lithium determinations using flame photometry and atomic absorption. Clin. Chem. 15, 787 (1969).

This Standard Reference Material has been measured and certified at the laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of this Standard Reference Material was February 23,

1972.

78
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Roberts, Director

^National ^nttnn of jitantlartte

Certificate of (Analysis

Standard Reference Material 925

4-Hydroxy-3-methoxy-DL-mandelic Acid (VMA)

A. J. Fatiadi and R. Schaffer

This Standard Reference Material is certified as a chemical of known purity. It is intended

primarily for use in the calibration and standardization of procedures employed in clinical analysis

and for routine critical evaluation of the daily working standards used in these procedures.

Purity 99.4 percent

Uncharacterized Compound maximum 0.5 percent

Keto-VMA maximum 0.1 percent

Volatile Matter 0.02 percent

Ash 0.004 percent

The value of purity has an estimated inaccuracy of 0.4 percent. The VMA for this Standard

Reference Material was prepared at the National Bureau of Standards. Analyses were performed by

A. Cohen, B. Coxon, E. R. Deardorff, R. A. Durst, D. P. Enagonio, A. J. Fatiadi, J. E. Fearn, B.

Greifer, G. Marinenko, W. P. Schmidt, and J. K. Taylor of the Analytical Chemistry Division.

The overall direction and coordination of technical measurements leading to certification were

under the chairmanship of R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard Reference Material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

Washington, D. C. 20234 J. Paul Cali, Chief

May 24, 1973 Office of Standard Reference Materials

Revised December 26, 1973

(over)

79
The Standard Reference Material, dried to constant weight in a vacuum desiccator over concentrated sulfuric acid, showed little tendency to gain weight when exposed to laboratory air for 24 h. Losses in weight on heating for 1 h at 56 °C at a vacuum of 0.1 mm Hg (13 Pa) averaged 0.017

percent, with little additional loss on further heating (1 h). Prolonged heating (8 h) caused gradual

decomposition.

The ash content was measured using 1.0-g samples.

Solutions of VMA exposed to light and air are unstable; originally colorless solutions turn pale

yellow on standing. The initial photo-oxidation product is keto-VMA (4-hydroxy-3-methoxybenzeneglyoxylic acid). A procedure for the preparation of the previously unreported keto-VMA

will be published. In acetone the rate of decomposition of VMA was found by spectrophotometry

at 335 nm to be about 1 percent per day. Solutions of VMA in water, ethyl acetate, or 0.01

mol/liter hydrochloric acid did not change appreciably (< 0.5 percent) during storage for three days

in the dark at room temperature, or when refrigerated for three months at 3-5 °C. Instability of

VMA in solutions exposed to air was found to be in the order acetone > water > ethanol>

methanol > ethyl acetate.

Analysis of the Standard Reference Material (SRM) by thin-layer chromatography (tic) revealed

two impurities. When 0.5mg of this SRM was applied as a spot on non-activated silica gel G plates,

developed with 4:4:1 (v:v:v) chloroform-acetic acid-water (solvent A) followed by spraying with 3

mol/liter sulfuric acid in methanol and heated for 2 min. in an oven at 110 °C showed VMA at Rp

0.63 and keto-VMA at R F 0.92. The amount of keto-VMA detected was equivalent to 0.5 - 1.0 jug

of the pure keto-VMA used as a standard. However, at least some of the keto-VMA is a chromatographic artifact. Two-dimensional tic revealed keto-VMA in two locations, originating respectively

from the positions that the VMA and the keto-VMA had occupied after the initial direction of

chromatography. Furthermore, tic of 0.1-mg quantities of keto-VMA with solvent A, followed by

sulfuric acid charring, revealed the presence of a small proportion of vanillin, possibly as an artifact

due to the instability of the keto-VMA in this chromatography. The second impurity, which is as yet uncharacterized, was revealed at RF 0.19 by tic of the SRM on silica gel GF with solvent A

followed by exposure to ammonia vapor and irradiation at 366 nm. (VMA and keto-VMA are also

detected by this technique.) With the silica gel GF and use of 1:1 (v:v) benzene-ethyl acetate or 5:4

(v:v) ethyl acetate-cyclohexane, the two impurities and the VMA were detected at RF values similar to those given with solvent A. An attempt was made to isolate the uncharacterized impurity from

50 mg of SRM 925 by means of preparative thin-layer chromatography. However, this impurity

underwent decomposition after being extracted and concentrated and was not detectable on chromatography by the previously employed technique. A definite proportion of the uncharacterized

impurity in the SRM could not be assigned, but it is assumed to be less than 0.5 percent.

Phase solubility analyses of the SRM with 1:1 (v:v) benzene-ethyl acetate and with 5:4 (v:v)

ethyl acetate-cyclohexane were performed by shaking mixtures for 8 days followed by gravimetric

analysis of the solutions. The purity of the VMA appeared to be in the range 99.6-99.9 percent;

however, tic showed that both impurities remained in the solid phase. Thus, the results of these

phase solubility analyses were not meaningful. In part this may be a consequence of the aforementioned instability of VMA.

Samples of VMA were titrated with standardized sodium hydroxide using a pH meter to the first inflection point of the titration curve. Complete titrations also were made in which both the

carboxyl and phenolic groups were titrated. The pH values at the 0.5 and 1.5 equivalent points were

3.75 and 9.80, respectively, corresponding to the pk, and pK2 for the compound. At the pH value

6.80, corresponding to the first inflection point, it was calculated that 99.91 percent of the

carboxyl group is titrated; accordingly, the acid equivalent measured was increased by 0.09 percent.

The sample contains a carboxylic acid equivalent of 99.83 percent.

80
The melting range (decomposition) of this SRM was 133-134 °C when measured in an open

capillary tube heated at 1 °C per min.

Elemental analysis. Calculated for C9 H 10 O5 (198.17); C = 54.54; H = 5.09; O = 40.37. Found:

C = 54.6; H = 5.1;0 = 40.3.

This Standard Reference Material was prepared at the National Bureau of Standards by slowly

adding glyoxylic acid to an ice-cold alkaline solution of guaicol, with mechanical stirring. The

product was purified by successive recrystallizations from ethyl acetate-cyclohexane and

2-butanone-cyclohexane mixtures. (Details of this one-step synthesis of VMA will be published.)

The synthetic material was further characterized by gas-liquid chromatography (GLC) after per(trimethylsilylation) with TRI-SIL-Z and showed Rt 17.2 min. using a glass column (1.8 m x 2

mm i.d.)of Chromosorb 0 (60-80 mesh) with 3 percent OV-17 as liquid phase, isothermal at 150 °C;

injection port at 180 °C,- ilame-ionization detector at 200 °C; nitrogen flow-rate at 25 ml per min.;

samples size 10 Mg in acetone (1 Atg//il). Infrared spectrum maxima (KBr pellet): 1870, 1748 and

1715 cm 1 (C=0 stretch). Nmr (methyl sulfoxide-d6 ): singlet at 6 3.80 (-OCH3 ), multiplet at 5 6.8

(aromatic protons), broad peak at 6 8.73 (-COOH). Ultraviolet spectrum: X max in 1.0 mol/liter

K2 C03 (10-15 min. after dissolution) at 251 nm (e M 1.022), 293 nm (0.429), and at 347 nm

(0.001).

Note: The use of proprietary designations in this certificate are for

information only, and should not be construed as an endorsement of

the product by either the Department of Commerce or the National

Bureau of Standards.

This Standard Reference Material is for "in vitro" diagnostic use only.

This material is for use as a standard in the determination of VMA (3-mcthoxy-4-hydroxymandelic acid) in clinical chemistry. A "stock" standard solution containing 1 mg/ml of VMA may

be prepared as follows. Accurately weigh 100 mg of SRM 925; transfer to a 100-ml volumetric flask and dissolve in 0.01N hydrochloric acid. Dilute the contents to the mark, and transfer to a glassstoppered, brown bottle. This solution should be stored in a refrigerator at 4 °C.

To prepare VMA solutions of lower concentration, the appropriate aliquot is pipetted into a 100-ml volumetric flask and diluted to the mark with 0.01N hydrochloric acid. These diluted

"working" standard solutions should be kept in a glass-stoppered, hrown bottle at 4 °C and dis- carded after one week [1,2]

.

This Standard Reference Material should be kept in the well-closed, original bottle and stored in a desiccator. Refrigeration at 4 °C, or preferably —20 °C, is recommended. The SRM and desiccator

should be allowed to warm to room temperature before opening. The SRM should not be subjected

to direct sunlight or to artificial ultraviolet sources. Standard Reference Material 925 is being kept

under close surveillance at NBS and if the material degrades beyond the limits certified, purchasers

will be notified by NBS. It is recommended that the material not be used after 5 years from the

date of purchase.

The "stock" standard solution containing 1 mg/ml, prepared as described above is stable for

about 3 months when stored in a glass-stoppered, brown bottle in a refrigerator at 4 °C. The dilute

"working" standard solution should be prepared weekly [1,2]

.

All constituted solutions of VMA should be clear and show no indication of turbidity.

81
References:

[1] Sunderman, F. W., Jr., Colorimetric determination of VMA in urine, in Standard Methods of

Clinical Chemistry, Vol. 6, R. P. McDonald, editor-in-chief, Academic Press, Inc., New York,

N. Y., 1970, pp 99-106.

[2] Tietz, N. W., Fundamentals of Clinical Chemistry, W. B. Saunders Co., Philadelphia, Pa. 1970,

pp 577-580.

This Standard Reference Material has been measured and certified at the laboratories of the

National Bureau of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of this Standard Reference Material was May 24, 1973.

82
U.S. Department of Commerce

Juanita M. Kreps

Secretary

National Bufletfti of Standards

Ernest Ambler, Acting Director ^National ^mtnix of j^tandartfe

Certificate

Standard Reference Material 926

Bovine Serum Albumin

(Total Protein Standard)

D. J. Reeder and R. Schaffer

This Standard Reference Material (SRM) is certified as a chemical of known purity. It conforms to the specifications for bovine serum albumin (lyophilized powder) approved by the National Committee for Clinical Laboratory Standards [1]. A 7-percent solution of this albumin is issued as a standardized solution (SRM 927) for use in the calibration and standardization of procedures for total serum protein determinations and for routine

critical evaluation of daily working standards used in these procedures.

Table 1. Certified Data

Constituent

Ash

Carbohydrate

Total hexose

Sum of citrate, pyruvate, lactate

Lipid (Total)

Non-protein amino compound,

as norleucine

Water

Karl Fischer method

Vacuum oven method

Protein impurities (Dimer)

Cellulose acetate Gel electrophoresis (polyacrylamide gel)

Gel chromatography (Sephadex)

Mass Fraction

Found

0.0006 ± 0.0001

0.000341 0.00003

0.00015 ± 0.00002

0.0003 ± 0.0003

0.00002 ± 0.00002

0.048

0.0475

: 0.002

: 0.0006

None detected

0.043 ±0.002

0.050 ±0.003

Spectral properties Ahsorhance

Ultraviolet, (A25 2/A2 79 ratio) 0.485 ±0.009

Soret band, (A4os at 70 g/L) 0.182 ±0.002

Visual, (A500 at 70 g/L) 0.048 ±0.002

(A6oo at 70 g/L) 0.023 ±0.002

The uncertainty is expressed as one standard deviation. The spelling "liter" and its symbol "L" are recom- mended usage in the United States (See Federal Register, Vol. 41, 54018, Dec. 10, 1976).

The bovine serum albumin used for this Standard Reference Material was prepared by the Research Division,

Miles Laboratories, Inc., Kankakee, Illinois. Analyses were performed by R. G. Christensen, A. Cohen, R. Deardorff, R. Durst, H. Hertz, B. Howell, S. Margolis, J. Maurey, D. J. Reeder, L. Sniegoski, P. Verdier, H. L. Wagner, F. W. Wang, and W. Yap.

The overall direction and coordination of technical measurements leading to the certification were under the chairmanship of R. Schaffer.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by T. W. Mears.

Washington, D.C. 20234

March 10, 1977

Revised July 18, 1977

J. Paul Cali, Chief

Office of Standard Reference Materials

(over)

83
The analytical techniques used in the certification of this Standard Reference Material are generally those

recommended in NCCLS Approved Standard: ACC-1 [1]. Non-protein amino compounds were determined

by fluorescence methodology [2].

Supplementary information for this Standard Reference Material is given in Table 2; the amino acid composition of the Bovine Serum Albumin in Table 3; and the fatty acid composition of the included lipid in Table 4. These data are not certified, but given for information only.

Table 2 — Supplementary information on SRM 926, Bovine Serum Albumin

Refractive index increment (dn/dc)(cm

3 /g) 0.18440 ±0 00025

Partial specific volume (in vacuo) (cm

3 / g) 0.7332 ±0.0007

Nitrogen analysis (Kjeldahl) (mg/g) 163.98 ±1.15

Immunoelectrophoresis No protein impurities detected

Molecular weight (g/mol)a 68,400 ±110

Number-average molecular weight of 7-percent solution, M„/c£ 9.73x10s ±0. 1 lxlO5

a Weight-average molecular weight, Mw , determined by equilibrium centrifugation.

b Determined by membrane osmometry, where Co is concentration of albumin standard (SRM 927).

Table 3 — Amino acid composition of SRM 926, Bovine Serum Albumin

Amino Acid Residues per 100 Residues

Aspartic acid 9. 13 Threonine 5.49 Serine 4.61 Glutamic acid 13.89

Table 4 — Fattv acid composition bv gas chromatoeraphv-mass spectrometry of the extracted lipid.

Proline

Glycine

Alanine

5.73 2.72

7.98

5.51 6.30

0.67

1.97 11.03 3.36 4.86

9.98

2.85

3.93

1/2-Cystine

Valine

Methionine

Isoleucine

Leucine

Tyrosine

Phenylalanine

Lysine

Histidine

Arginine

Tryptophan Not determined

Compound,

Methyl benzoate

Methyl decanoate

Methyl dodecanoate

Methyl tetradecanoate (myristate)

Methyl pentadecanoate

A phthalate ester Methyl hexadecenoate <a|

Methyl hexadecanoate (palmitate)

Dibutyl phthalate

Methyl oleate Methyl octadecanoate (stearate)

Methyl eicosanoate

Relative Amount

4.4

3.0

3.9 10

6.9

7.1 20

45

100

12 23

8.1

a = probable identity

84
This Standard Reference Material is intended for "in vitro" diagnostic use only.

This Standard Reference Material should be stored in a well-closed container at a temperature not to exceed

4 °C. Storage in a desiccator is recommended. It should not be subjected to sunlight or ultraviolet radiation. Under proper storage, this SRM is expected to be stable for at least 3 years. Samples of this material will be

monitored and should the certified properties degrade beyond the limits specified, purchasers will be notified by

NBS. It is recommended that material not be used after 3 years from date of purchase.

The lyophilized Standard Reference Material is extremely hygroscopic and will generally increase in moisture

content under most weighing conditions. It is recommended that, for applications requiring only portions of

the material, the container should be opened and samples weighed under controlled atmospheric conditions,

e.g., a dry nitrogen atmosphere in a glove box or similar type of isolation chamber.

Albumin solutions may be prepared from the lyophilized albumin powder by adding the powder to the surface of the liquid and allowing the powder to dissolve by diffusion into the liquid. Avoid disturbing the solution

during this process. If dry powder is present when the solution is mixed,the clumps that formed will be found

sparingly soluble and may take several days to dissolve.

The SRM should not be used if the material takes on a color other than the normal white appearance. Another

sign of degradation of the albumin is insolubility of the powder when preparing solutions at a concentration of

1% or less.

References:

[I] Standardized Protein Solution (BovineSerum Albumin), Approved Standard: ACC-1, National Committee

for Clinical Laboratory Standards, Villanova, Pa., 1972.

[2] Reeder, D.J., Sniegoski, L.T., and Schaffer, R., o-Phthalaldehyde for the Fluorimetric Assay of Nonprotein Amino Compounds, submitted for publication to Clinical Chemistry.

This Standard Reference Material has been measured and certified at the Laboratories of the National Bureau

of Standards, Gaithersburg, Maryland. All inquries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of this Standard Reference Material was March 10, 1977. NOTE: The use of proprietary names are for identification purposes only and do not constitute NBS endorsement of any particular product.

85
U.S. Department of Commerce

Juanita M. Kreps

Secretary

National Bu1*«u of Standards

Ernest Ambler, Acting Director ^National l&mtnvc of Standards

Certificate

Standard Reference Material 927

Bovine Serum Albumin (7% Solution)

(Total Protein Standard)

Dennis J. Reeder and Robert Schaffer

This Standard Reference Material (SRM) is certified as a solution of known protein concentration and purity.

It conforms to the specification for standardized protein solution approved by the National Committee for Clinical Laboratory Standards (NCCLS) [1]. SRM 927 was prepared from the same lot of bovine serum

albumin as SRM 926, brought to proper ionic strength with sodium chloride and to proper pH with sodium

hydroxide. It was sterilized by membrane filtration. This SRM is intended primarily for use in the calibration

and standardization of procedures employed in clinical analyses for total serum protein determinations and for routine critical evaluation of daily workmg standards used in these procedures.

Table 1. Certified Data

Peptide mass (g/L)*

Biuret method [2] 70.45 ±0.10

Kjeldahl method 70.48 ± 0.50

Method using optical density at 278 nm 70.77 ± 0.23 pH 6.66 ± 0.01

Sodium ion, substance concentration (mol/L) 0.0291 ± 0.0004

Chloride ion, substance concentration (mol/L) 0.0210 ± 0.0002

Volume (mL) 2.06 - 2.28 The spelling of "liter" and its symbol "L" are recommended usage in the United States (Federal Register, 41,

51089, December 10, 1976).

The inaccuracies expressed in the above table are one standard deviation (a), except for the peptide mass by

biuret method. In the analysis of the biuret data, regression curves were developed for three separate experiments involving at least 80 separate correlated measurements. Thus, the final data is expressed in terms of

standard error (a//n), rather than standard deviation.

The bovine serum albumin solution was prepared by the Research Division, Miles Laboratories, Inc., Kankakee, Illinois. Analyses were performed by R. G. Christensen, A. Cohen, R. Deardorff, R. Durst, H. Hertz, B. Howell, S. Margolis, J. Maurey, D. Reeder, L. Sniegoski, W. Yap, P. Verdier, and H. L. Wagner.

The overall direction and coordination of technical measurements leading to the certification were under the

chairmanship of R. Schaffer.

Washington, D.C. 20234 George A. Uriano, Chief

December 31,1 979 Office of Standard Reference Materials

(Revision of Certificates dated 3-16-77 and 7-18-77) (over)

86
This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is for use as a standard in clinical chemistry. It is intended for use primarily as a reference standard for assays of total protein by colorimetric methods. A biuret method [2], modified to a 60-minute

incubation, was employed to assay the comparison solutions prepared from SRM 926, and the standardized

ampouled solution. It is suggested that this biuret method be used to standardize laboratory-prepared protein

solutions and "normal" serum pools. Such standardized "normal" sera could then be used to calibrate re- fractometers or other instruments for serum protein estimations. Standard Reference Material 927 may be

used for other procedures, such as gel diffusion, amino acid analysis, electrophoresis, nitrogen assays, or other

tests which require well-characterized protein.

WARNING

This Standard Reference Material is not to be used in standardizing dye-binding tests, for directly checking pre- calibrated refractometers, or as an immunochemical standard. It is not recommended for use in billirubin standardization.

Protein solutions of lower concentration may be prepared by transfer of the appropriate aliquot to a 25-mL

volumetric flask and diluted. Diluents are not furnished with the Standard Reference Material. An aqueous

diluent, such as 0.15 mol/L sodium chloride solution, may be used.

This Standard Reference Material is supplied to the user in sealed ampoules. It must be stored such that the temperature of the solution does not exceed 4 ° C; nor may the solution be allowed to freeze. Once an ampoule is opened, the solution should be used promptly. Storage of opened ampoules is not recommended. Under proper

storage in sealed ampoules this SRM is expected to be stable for 3 years. Stocks of this SRM kept at NBS will be

monitored and if degradation is evident, purchasers will be notified. It is recommended that this material not be

used after 3 years from date of purchase.

References:

[1] Standardized Protein Solution (Bovine Serum Albumin), Approved Standard: ACC-1, National Committee for Clinical Laboratory Standards, Villanova, Pa., 1972.

[2] B. T. Doumas, Standards for Total Serum Protein Assays - A Collaborative Study. Clin. Chem. 21 (8), 1159-1166 (1975).

[3] United States Pharmacopeia, 18th Revision, p. 855, Class A, United States Pharmacopeial Convention,

Rockville, Md. 1970 (see also 19th Revision, p. 712, 1975).

This Standard Reference Material has been measured and certified at the laboratories of the National Bureau

of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B311, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of this Standard Reference Material was March 16, 1977.

87
The sterile ampouled solution used for this Standard Reference Material was prepared from the same lot of

bovine serum albumin as SRM 926. The following properties, which equal or exceed those required by NCCLS

Approved Standard ACC-1, were measured on aqueous solutions of SRM 926. The uncertainties are expressed

as one standard deviation.

Constituent

Ash

Carbohydrate

Total hexose

Sum of citrate, pyruvate, and lactate

Lipid (total)

Non-protein amino compound, as norleucinei

Water

Karl Fischer method

Vacuum oven method

Protein impurities (Dimer)

Cellulose acetate Gel electrophoresis

Gel chromatography

Spectral properties

Ultraviolet (A252 /A 279 ratio at 70 g/L)

Soret band (A405 at 70 g/L)

Visual (A5 oo at 70 g/L)

(A60o at 70 g/L)

Mass Fraction Found

0.0006 ± 0.0001

0.00034

0.00015

0.00003

0.00002

0.0003 ± 0.0003

0.00002 ± 0.00002

0.048 ± 0.002

0.0475 ± 0.0006

None detected

0.043 ± 0.002

0.050 ± 0.003

Absorbance

0.485 ± 0.009

0.182 ±0.002

0.048 ± 0.002

0.023 ± 0.002

The certified protein concentration is based on the mass of polypeptide material dissolved per liter of solution,

where peptide material is defined as albumin powder less its content of ash, carbohydrate, lipid, non-protein

amino compounds, and water.

Supplementary information on SRM 926, Bovine Serum Albumin

Refractive index increment (dn/dc) (cm3 /g) Partial specific volume (in vacuo) (cm /g)

Nitrogen analysis (Kjeldahl) (mg/g)

Immunoelectrophoresis

Molecular weight

3

Number-average molecular weight of albumin (as 7-percent

solution)

0.1 8440 ± 0.00025

0.7332 ± 0.0007

163.98 ± 1.15 No protein impurities detected

68,400 ±110

68,500 ± 780

Weight-average molecular weight, Mw, determined by equilibrium centrifugation. Value determined by membrane osmometry which gave Mn/Co = 9.73 x 10

5 ± 0. 1 1 X 10 mL/mol, where Mn is the number-average

molecular weight and Co is the concentration of albumin standard (SRM 927).

88
U.S. Department of Commerce

Elliot L. Richardson,

Secretary

National Bureau of Standards

Ernest Ambler, Acting Director

Rational ££uram of jltandante

Certificate of ^ttalgst*

Standard Reference Material 928

Lead Nitrate

(Clinical Standard)

This Standard Reference Material is certified for use as an assay standard for lead. It is intended

primarily for use in the calibration and standardization of procedures employed in clinical analysis

and for the routine critical evaluation of daily working standards used in these procedures.

Assay 100.00 ± 0.03 percent

The assay shown is based on the determination of lead in the material as received; drying being

unnecessary. Lead is precipitated as the chromate using a slight excess of potassium dichromate

(SRM 136c). The lead chromate is removed by filtration and the excess chromate ion determined

spectrophotometrically. Details of this method are reported elsewhere [ 1 ]. The molecular weight of

lead nitrate employed in the calculation is 331.219. This value is based on a mass-spectrometrically

determined value of 207.209 for the atomic weight of lead in this sample. The uncertainty shown

represents two standard deviations of a single measurement based on 16 determinations with

allowances for known sources of possible error.

A semi-quantitative survey for trace metals by emission spectroscopy indicated the following: silver,

2fig/g; chromium, 3 ngjg; nickel, 3/jg/g. No other metals were detected.

The lead nitrate used for this Standard Reference Material was obtained from the J. T. Baker

Chemical Co., Phillipsburg, New Jersey. Chemical analyses were performed by T. J. Murphv

and J. W. Gramlich. Spectroscopic analyses were performed by C. S. Annell and D. Golightly of the

United States Geological Survey.

The overall direction and coordination of technical measurements leading to certification were

under the chairmanship of I. I,. Barnes.

The technical and support aspects concerning preparation, certification, and issuance of this Standard Reference Material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

Washington, D.C. 20234 J. Paul Cali, Chief

February 27, 1976 Office of Standard Reference Materials

Revised May 19, 1976

(over)

89
This material was examined for compliance with the specifications for reagent grade lead nitrate as given in Reagent Chemicals, 5th edition, published by the American Chemical Society. The material

met or exceeded the requirements in every respect.

This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is intended for use as a standard for lead determination in clinical chemistry.

Because of the instability of non-acidified aqueous lead solutions at the working levels it is recommended [2] that three levels of concentration be used.

(a) A stock standard solution containing 50 mmol/l is prepared by dissolving 1.6561 g of SRM

928 in ion-free water. If the solution is cloudy or a precipitate forms, add a few drops of

ammonium hydroxide. Mix, dilute to 100 ml in a calibrated volumetric flask and transfer

immediately to a previously acid-washed, water-rinsed, dry polyethylene bottle. This

solution is stable for six months. [2]

.

The above directions are directly quoted from the reference given. Users are cauuoned that

carbonate-free ammonium hydroxide not in excess of 0.2 ml should be added. Otherwise,

insoluble basic lead salts will form. However, experience at NBS indicates that this material

will easily dissolve without cloudiness when high-purity water is used.

(b) An intermediate solution containing 500 Mmol/l is prepared by a 1:100 dilution of the above

stock solution. This solution may be stored in a capped polyethylene bottle at room

temperature for one month [2]

.

(c) Working standard solutions of 0.5, 1.0, 2.5, and 5.0/umoles/l should be prepared each time

an analysis is performed [2]

.

Note: Dilute aqueous lead standards remain stable for less than three hours. Lead is readily

adsorbed on the surfaces of glass and plastic containers and this reaction is accelerated by

exposure to light, particularly ultraviolet light [3] . It is recommended that very dilute

aqueous lead solutions be prepared in a darkened room and protected from light [4]

.

This Standard Reference Material should be stored in the tightly-closed original bottle under normal

laboratory conditions. Tests show the material to be dry as received and not to adsorb appreciable

water when exposed to a 90 percent relative humidity atmosphere for 5 days.

The solutions of SRM 928 are stable as described above. At time of use these solutions should be

clear and display no turbidity.

References:

[1] E. I. Catanzaro, T. 1. Murphy, W. R. Shields and E. L. Garner, J. Res. NBS 72A, 261-267

(1968).

[2] L. Kopito and H. Shwachman, Measurement of lead in blood, urine, and hair by. atomic

absorption spectroscopy, Standard Methods of Clinical Chemistry, Vol. 7, G. R. Cooper,

editor-in-chief, pp. 151-162, Academic Press, Inc., New York, N.Y. 1972.

[3] L. Kopito and H. Shwachman, J. Lab. Clin. Med. 70, 326-332 (1967).

[4] Fundamentals of Clinical Chemistry, N. W. Tietz, editor, pp. 852-857, W. B. Saunders Co.,

Philadelphia, Pa. (1970).

The date of issuance and certification of this Standard Reference Material was June 15, 1975.

90
U.S. Department of Commerce

•luanita M. Kreps

Secretary

i * I National Bureau ot Standards

Ernest Ambler, Director

This Standard Reference Material is certified for use as an assay standard for magnesium. It is intended

primarily for use in the calibration and standardization of procedures employed in clinical analysis and for the

routine critical evaluation of daily working standards used in these procedures. The material is highly purified

magnesium gluconate dihydrate, Mg (QHi |0?)2 - 2H20.

This certified value is based on a minimum sample of 25 mg of the material dried to constant weight for at least 24 hours over anhydrous magnesium perchlorate. The certified value is based on the determination of

magnesium in the dried material by thermal ionization isotope dilution mass spectrometry. Details of this method are reported elsewhere [1].

For mass spectrometric analysis, two different methods of magnesium separation were used. The uncertainty;

0.022, is the sum of: 0.014, the possible systematic differences between the methods; and 0.008, the 95 percent

confidence limit for the mean.

The magnesium gluconate dihydrate used for this Standard Reference Material was obtained from the J.T. Baker Chemical Co., Phillipsburg, N.J.

The analyses were performed by L.A. Machlan, J.R. Moody, and L.J. Moore of the NBS Inorganic Analytical

Research Division.

The statistical evaluation of the data was performed by H.H. Ku, NBS Statistical Engineering Division.

The overall direction and coordination of the technical measurements leading to certification were under the chairmanship of I.L. Barnes.

The technical and support aspects concerning preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by R.W. Seward.

Washington, D.C. 20234 George A. Uriano, Acting Chief

April 27, 1979 Office of Standard Reference Materials

Standard Reference Material 929

Magnesium Gluconate Dihydrate

(Clinical Standard for Magnesium)

MAGNESIUM, weight percent: 5.403 ± 0.022

(over)

91
The water of hydration was determined on the dried material (see above) by the Karl-Fischer method using dry

methanol and dimethyl sulfoxide (80:20) solvent. The water content was found to be 7.99 weight percent, which

is in agreement with the theoretical value of 2 moles of water per mole of salt, 8.00 weight percent. Determination of water content was performed by S.A. Margolis, NBS Organic Analytical Research Division.

This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is intended for use as a standard for magnesium determination in clinical chemistry.

STORAGE: Standard Reference Material 929 should be stored in the tightly-closed, original bottle under

normal laboratory conditions. Tests show this material to be hygroscopic and must be dried as directed before

use; such drying will not remove water of hydration. Stored under these conditions, this material will show no

significant change in properties. NBS will keep this lot under surveillance for five years after the date of last

sale. If degradation occurs beyond the limit certified, NBS will notify purchasers. In the absence of such

notification, the user should not use the material beyond five years after the purchase date. A standard solution containing 5.00 mmol/L of magnesium may be prepared by placing 1.125 g of dried SRM

929 in a 500 mL volumetric flask and dissolving the material with laboratory reagent grade water.* Lower

concentrations required for analysis may be prepared by accurate dilutions.

Solutions of SRM 929 prepared as above are stable for at least 60 days under normal laboratory conditions.

[1] Catanzaro, E.J.; Murphy, T.J.; Garner, E.L.; and Shields, W.R., J. Res. NBS 70A, No. 6, 553-558(1966).

* Laboratory reagent grade water meeting any of the following specifications:

American Society for Testing and Materials (ASTM), Dl 193-Type II; College of American Pathologists (CAP), Type II; National Committee for Clinical Laboratory Standards (NCCLS), Type I.

92
U.S. Department of Commerce

Juantta M. Kreps

Secretary

National BuCee*] of Standards

Ernest Ambler, Acting Director Rational ^@ttram af jitatulartte

(Certificate

Standard Reference Material 930D

Glass Filters for Spectrophotometry

R. Mavrodineanu and J. R. Baldwin

This Standard Reference Material is intended as a reference source for the verification of the transmittance

and absorbance scales of spectrophotometers. It consists of three individual glass filters in their metal holders

and one empty filter holder. The holders are provided with shutters to protect the glass filters when not in use. These shutters must be removed at the time of measurements and be replaced after the measurements have been

completed. Each filter bears an identification number, and the upper left corner has been removed to indicate correct placing in the metal holder.

Filter & Set

Ident. Number

TRANSMITTANCE (T) TRANSMISSION DENSITY (-log,0T)

Wavelength and (Bandpass)

nm

Wavelength and (Bandpass)

nm

440.0

(2.2)

465.0

(2.7)

546.1

(6.5)

590.0

(5.4)

635.0

(6.0)

440.00

(2.2)

465.0

(2.7)

546.1

(6.5)

590.0

(5.4)

635.0

(6.0)

1- 930

2- 930

3- 930

0.0923

0.1920

0.2929

0.1096

0.2161

0.3193

0.1023

0.2059

0.2993

0.0923

0.1918

0.2745

0.1032

0.2069

0.2777

1.035

0.717

0.533

0.960

0.665

0.4958

0.990

0.686

0.524

1.035

0.717

0.561

0.987

0.684

0.556

Date of Certification: January 1, 1981

The transmittance values (T) can be converted to percent transmittance (%T) by multiplying by 100. The

transmission densities are calculated from the measured transmittance (T). These values should be indicated by

the absorbance scale of the spectrophotometer if the filters are measured against air. The transmittance values

given were measured against air at an ambient temperature of 23.5 °C.

The transmittance values are estimated to be accurate to within ±0.5 percent at the time of certification. This

uncertainty includes the effects of the random and systematic errors of the calibration procedure, as well as possible transmittance changes of the filters during the period of calibration.

Aging of the glass may cause some filters to change transmittance by about ± 1 percent over a period of approximately one year from the date of calibration. Improper storage or handling of the filters may also cause changes

[5]. It is recommended that the filters in the holders be handled only by the edges with soft plastic (polyethylene)

gloves and optical lens tissue. When not in use they should be stored in their holders and in the container

provided for this purpose. Extended exposure to laboratory atmosphere and dusty surroundings should be

avoided. In cases where verification is desirable, the filters should be returned to the National Bureau of

Standards for cleaning and recalibration.

This Standard Reference Material was issued with the assistance and advice of K. D. Mielenz and J. R. DeVoe.

The technical and support aspects involved in the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by T. W. Mears and

R. W. Seward.

Washington, D.C. 20234

August 1, 1977

(over)

J. Paul Cali, Chief

Office of Standard Reference Materials

93
The transmittance measurements were made using the high-accuracy spectrophotometer designed and built at the NBS Institute for Materials Research [1]. This instrument represents the primary transmittance standard;

its transmittance accuracy was established using the double-aperture method of linearity testing [1,3,5,6]. The

estimated standard deviation obtained from a set of 20 measurements of the high-accuracy spectrometer used

for transmittance measurements on glass filters of the SRM 930 type is 5 x 10

5 transmittance units for transmit- tance between 0. 1 and 0.3. The bounds of the systematic error of the instrument are estimated to be +10 ''trans- mittance units.

The neutral glasses for the filters were provided by Schott of Mainz, Germany, and are designated as "Jena Color and Filter Glass." The glass material was prepared by the manufacturer especially for SRM 930. It was

fine-annealed and was selected for best homogeneity and minimum of inclusions and striae. The glass filters were aged at NBS for about one year prior to certification. They are of the type NG-4 and NG-5, and their nominal transmittances are 10, 20, and 30 percent [2,5]. The glasses were selected to provide a means to verify the transmittance scale of conventional spectrophotometers at three levels. The exposed surface of the glass is approximately 29 x 8 mm, measuring from a point 1.5 mm above the base of the filter holder (see figure). The

empty filter holder is provided to be used in the reference beam of the spectrophotometer so that approximately

equivalent conditions of stray radiations are achieved for both beams.

The transmittance of the filters depends upon the intrinsic properties of the material, wavelength, spectral bandpass, geometry of the optical beam, temperature, and positioning of the filter. A change of ambient temperature

of 1 or 2 °C from 23.5 °C will not significantly affect the calibration [5]. Changes in the transmittance may be

caused by surface conditions, aging of the glass, exposure to a harmful atmosphere, or careless handling as indicated on the face of this certificate [2,3,4,5]. The effective spectral bandpasses used to determine the certified values are given on the face of the certificate and the transmittance measurements are made by producting the

vertical image of the slit (about 8 mm by 0.5 mm), using a convergent beam geometry with an aperture ratio f: 10,

in the middle of the entrance face of the glass filter. The filters were measured in the spectrophotometer in a

position perpendicular to the incident light beam as shown in the attached figure.

SRM 930D is stored in a black anodized aluminum container provided with a threaded cap made of the same

metal. Each filter is placed in a cylindrical cavity to prevent any contact between the filter face and the walls of

the storage container. Contamination of the glass filter surface with particulate matter due to static charges is minimized through the metallic nature of the container. Each filter holder is provided with a flat leaf spring

which is inserted into the cylindrical cavity to minimize damage during transportation. These springs can be

removed during normal use in the laboratory.

Prior to certification measurements, each filter was examined for surface defects and thorougly cleaned [5]. Should the surface of the glass filter become contaminated, no attempt should be made to clean it unless the user has the facilities to demonstrate that the cleaning treatment has not altered the glass surface or degraded the accuracy of the certified values. As the Standard Reference Material is a transfer standard, the only means

available to verify its integrity is remeasuring its transmittance with a primary standard instrument similar to

that used in this certification [1,4,5]. In most cases where verification, or recertification, of the transmittance

values is desirable, it will be most expeditious to return the filters to the National Bureau of Standards for measurement. Prior to shipment, the NBS Office of Standard Reference Materials should be contacted regarding the conditions and cost of verification and/or recertification. We wish to acknowledge the cooperation of George N. Bowers, Jr., M.D., of Hartford Hospital, Hartford,

Connecticut; Royden N. Rand, Ph.D., of the Eastman Kodak Co. Research Laboratories, Rochester, New

York; and Donald S. Young, M.D., Ph.D., of the National Institutes of Health, Bethesda, Maryland.

94
REFERENCES

1. R. Mavrodineanu, An Accurate Spectrophotometer for Measuring the Transmittance of Solid and Liquid

Materials, NBS Journal of Research 76A, No. 5, 405^25 (1972).

2. R. Mavrodineanu, Solid Materials to Check the Photometric Scale of Spectrophotometers, NBS Tech. Note

544, O. Menis and J. I. Shultz, Eds., pp. 6-17, U.S. Government Printing Office, Washington, D.C. 20402

(Sept. 1970); ibid, NBS Tech. Note 584, pp. 2-21 (December 1971).

3. K. S. Gibson, Spectrophotometry, NBS Circ. 484 (Sept. 1949).

4. Collected Papers from NBS Conference on Accuracy in Spectrophotometry and Luminescence Measurements, NBS Journal of Research 76A, No. 5, 375-510 (1972).

5. R. Mavrodineanu and J. R. Baldwin, Glass Filters as a Standard Reference Material for SpectrophotometrySelection, Preparation, Certification, Use, SRM 930, NBS Special Publication 260-51, U.S. Government

Printing Office, Washington, D.C. 20402, 1975.

6. K. D. Mielenz and K. L. Eckerle, Spectrophotometer Linearity Testing Using the Double-Aperture Method,

Appl. Optics 11, 2294-2303 (1972).

METAL HOLDER FOR THE COLORED GLASS FILTERS*

00?

FRONT TOP

BASE

1.5

DIMENSIONS in mm

.METAL HOLDER

57 X 13 X 13

EXPOSED FILTER SURFACE

29 X 8

COLORED GLASS FILTER

30.5 X II X 2.0 (Of 1,5)

*Shutters not illustrated.

95
U.S. Department of Commerce

Juanita M. Kreps

Secretary

National Huteau of Standards

Ernest Ambler; Acting Director ^National ^mtan of Standards

Certificate

Standard Reference Material 931b

Liquid Absorbance Standards for

Ultraviolet and Visible Spectrophotometry

R. W. Burke and E. R. Deardorff

This Standard Reference Material is certified as solutions of known net absorbance at specific spectral wavelengths. It is intended primarily for use in the calibration and checking of accuracy of the photometric scale of narrow bandpass spectrophotometers employed in clincial analysis and for routine critical evaluation of daily

working standards used in clinical spectrophotometry. This Standard Reference Material is applicable for cali- brating those instruments that provide an effective spectral bandpass of 1 .5 nm or less at 302 nm, 2.0 nm or less at 395 nm, 3.3 nm or less at 512 nm and 8.5 nm or less at 678 nm [1].

Filter

Net Absorbance

3

Wavelength and (Bandpass), nm

302(1.0) 395(1.7) 512(2.0) 678(6.5)

"I" - "Blank"

"II" -"Blank"

"III" - "Blank"

0.306 ± 0.003

.607 ± .004

.891 ± .005

0.302 ± 0.003

.605 ± .004

.902 ± .005

0.300 ± 0.003

.602 ± .004

.899 ± .005

0.115±0.002

.230 ± .003 .342 ± .003

Net absorbances ("I" - "Blank", "II" - "Blank", and "III" - "Blank") were determined using 10.00 mm cuvettes (SRM 932) at 25 °C. See

Instructions for Use.

Absorbance measurements were performed on a high precision double-beam spectrophotometer equipped with

a double monochromator. The accuracy of the photometric scale of this instrument was established with the NBS high-accuracy spectrophotometer described by Mavrodineanu [2]. The uncertainties of the certified values

include all known sources of possible systematic error and the 95 percent confidence level for the mean.

While no long-term stability studies have been made on this lot (931b), studies on previous lots (931 and 931a) over a three-year period showed no degradation of the material when stored in the original sealed ampoules.

Nevertheless, until additional information is forthcoming, it is recommended that this material not be used after three years from the date of purchase.

The overall direction and coordination of technical measurements leading to certification were performed under

the chairmanship of I. L. Barnes.

The technical and support aspects involved in the' preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by W. P. Reed.

Washington, D.C. 20234 J. Paul Cali, Chief

November 10, 1977 Office of Standard Reference Materials

(over)

96
Temperature Dependence

Absorbances at various temperatures (17 to 35 °C) may be calculated using the equation

At =A25 [l+CA(t-25)],

where: At = Absorbance at temperature t (°C)

A25 = Absorbance certified at 25.0 °C

Ca = Fractional change in absorbance per °C

The values of Ca, at the four wavelengths, are given below. [NOTE: At wavelength 302 nm, absorbance

decreases with increasing temperature; at the other wavelengths, absorbance increases with increasing temperature.]

Wavelength, nm Ca

302 -0.0014

395 +0.0014

512 +0.0018

678 +0.0014

Preparation of Filters

The filters were prepared by dissolving high-purity cobalt and nickel in a mixture of nitric and perchloric acids. The absorbance spectrum of the icsulting solution is shown in the following figure. The maxima at 302 and 512

nm are due to absorbance by NO3- and Co(H20)V, respectively. The maximum at 395 nm and the plateau at 650-700 nm are due to Ni(H20)6? The pH of these solutions is about 1.

ABSORftftNCE 302 393 912

300 Site 5oT5 7O0

WAVELENGTH, nm

Warning

This Standard Reference Material is intended for "in vitro" diagnostic use only.

Instructions for Use

This material is for use as a spectrophotometric absorbance standard.

1. Select two clean 10.00 mm cuvettes free of scratches. At least one should be fitted with a ground glass or Teflon stopper to minimize evaporation. Reserve it for all sample measurements.

2. Mark each of the cuvettes to assure the same orientation in the spectrophotometer.

3. Place the cuvettes in their respective holders and fill with distilled water. (Borosilicate Pasteur-type pipettes

fitted with rubber bulbs are recommended for transferring all solutions to and from the cuvettes. Soft glass

pipettes, which are available coniim_.cially, contain residual amounts of ultraviolet absorbing material, but

may be used after proper cleaning. Several rinses, first with isopropyl alcohol and then with distilled water, are generally adequate.)

4. Obtain the optical mismatch of the cuvettes at 302, 395, 5 1 2, and 678 nm, using the spectral bandpass limita- tions given on the face of the certificate.

5. Empty the cuvettes by suction without removing them from their holders, refill with distilled water and

measure the absorbances again at each of the above wavelengths.

97
6. Repeat the emptying and refilling operation until constant absorbance readings are obtained.

7. Using the liquid filters provided, measure, in turn, the absorbance of the "Blank", "I", "II", and "III" against

distilled water. Shake each ampoule before opening to remix any condensate which may have collected in the neck. (The ampoules have been prescored directly below the gold band to facilitate opening.)

8. Subtract the appropriate "Blank" reading from the absorbances obtained for'i", "II", and "III". These net absorbances should agree with the certified values within the uncertainties specified. Consult the manufacturer of the instrument if they do not.

The above instructions are for use with the standard 10-mm rectangular cuvette. For calibration of the several spectrophotometric systems used in various automated instruments, the user is referred to the instruction

manual for the particular instrument.

The absorbances of these liquid absorbance standards will depend not only on the accuracy of the photometric

scale, but also on the wavelength accuracy and the spectral bandpass. A mercury lamp is recommended for checking the wavelength scale. In addition, for those spectrophotometers having a hydrogen (H) or deuterium

(D) source, the two emission lines at 486. 1 and 656.3 nm (H) or 486.0 and 656. 1 nm (D) may provide a convenient

check at these wavelengths.

To insure that the measured absorbances are not significantly different from the certified values, the following

restrictions are placed on the size of the spectral bandpass selected: To obtain ±0. 1 percent of the true value, the

effective spectral bandpass should not exceed 1 .5, 2.0, 3.3, and 8.5 nm at 302, 395, 512, and 678 nm, respectively.

For ±0.2 percent, the respective bandpasses should not exceed 2.2, 2.9, 4.8, and 12.3 nm. Additional information on the effect of spectral bandpass on the absorbances of these filters is given in the figure below. These

curves are not to be used, however, to correct the measured absorbances.

+ 2.00

+1.00

o 0.00

§

-i-oo

Ixl ^ -2.00

<

m

£ -3.00

o

CO3 -4.00

-5.00

0 2 4 6 8 10 12 14 16 18

EFFECTIVE SPECTRAL BANDPASS, nm

This Standard Reference Material should be kept in the original sealed ampoules. Once opened, the material

should be used immediately. No attempt should be made to reseal the ampoule. In addition, it is recommended

that this Standard Reference Material not be used after three years from the purchase date.

References

[1] R. W. Burke, E. R. Deardorff, and O. Menis, J. Research.Nat. Bur. Stand. 76A, 469-482 (1972).

[2j R. Mavrodineanu, J. Research.Nat. Bur. Stand. 76A, 405-425 (1972).

Note: The above papers are also published in NBS Special Publication 378, Accuracy in Spectrophotometry and Luminescence Measurements, R. Mavrodineanu, J. I. Shultz, and O. Menis, editors, U.S. Government Printing Office, Washington, D.C. 20402, 1973.

678 nm

^\5l2nm

302nrr\

1

1 1 1 1

\ 395 nm

i i \i i

98
U.S. Department of Commerce

Juanita jtf. Kreps

(Eerttficate

Standard Reference Material 932

Quartz Cuvette for Spectrophotometry

R. Mavrodineanu and J. W. Lazar

This Standard Reference Material consists of a single, accurately calibrated cuvette that is issued for use in the production of accurate spectrophotometric data on liquids. The design and nominal dimensions of the all- quartz cuvette are shown in Figure 1. The pathlength of the cuvette is defined by the distances between the two

optically transparent windows taken at several heights within the cuvette. Cuvettes issued as Standard Refer- ence Material 932 have a nominal pathlength of 10 mm. The pathlength and parallelism are certified with an uncertainty of ±0.0005 mm as determined by measurements (at 20° C) taken at the positions indicated below.

Cuvette number is issued with this certificate. For this cuvette the following measurements were

The cuvette must be handled with great care and should be held only by the frosted-quartz side windows. When

not in use, it should be stored in the container provided for this purpose. Extended exposure to laboratory

atmosphere and dusty surroundings is to be avoided.

The overall direction and coordination of the technical measurements leading to certification were performed

under the chairmanship of O. Menis and J. A. Simpson.

The technical and support aspects involved in the preparation, certification .and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by T. W. Mears.

Washington, D.C. 20234 J. Paul Cali, Chief

August 2, 1978 Office of Standard Reference Materials

(Revision of certificates dated 1 1-5-73 and 6-16-77) (over)

obtained.

Height Pathlength

mm mm

99
The original cuvettes were designed and produced at the National Bureau of Standards using special techniques

and non-fluorescent optical-quality fused silica as described in NBS SP 260-32 [

1]. The transparent windows are attached to the body of the cuvette by direct fusion, and the unit was stress-relieved by annealing. The overall

flatness of each surface of a transparent window is within two fringes (546 nm Hg line). The radiation pathlength

measurements of the cuvette were performed using electronic feeler-gauge type instruments capable of a resolu- tion of 5 parts in 10 . The development and production of SRM 932 is a result of the combined efforts of the Center for Analytical Chemistry, the Center for Mechanical Engineering and Process Technology, and the Instrument Shops Division. E. P. Muth and E. I. Klein designed and assembled the cuvettes, respectively.

Since January 1977, the cuvettes issued as SRM 932 have been prepared by Starna, Ltd., Dayenham, Essex, U. K., in accordance with NBS techniques and specifications described in NBS SP 260-32. The radiation pathlength measurements of all of these cuvettes, regardless of manufacturer, have been performed by E. G. Erber of

the Mechanical Processes Division.

Reference:

[1] Mavrodineanu, R., and Lazar, J. W., Standard Reference Materials: Standard Quartz Cuvettes for High

Accuracy Spectrophotometry, Nat. Bur. Stand. (U.S.), Spec. Publ. 260-32 (December 1973). Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402, 55 cents.

10-

RADIATION

PATHLENGTH"

1.25-

i 't- M 10

6 TOP

SIDE

48

(FROSTED)

FRONT

(TRANSPARENT)

BOTTOM

I I -H 12.5 KTOP

MEASUREMENT

LEVEL

BOTTOM

MEASURMENT

LEVEL

INCIDENT RADIATION BEAM

100
U. S. Department of Commerce

Frederick B. Dent

Secretary

National Burwi of Standards

Richard W. Roberta, Director^attmtal ££uram of Standards

(Etrttfttat*

Standard Reference Material 933

Clinical Laboratory Thermometer

This Standard Reference Material is intended for use in clinical laboratories as a primary cali- brant, particularly in the area of clinical cnzymology. It is comprised of three individually-calibrated

thermometers. The certified corrections for each thermometer, as a computer print-out sheet, are attached, together with information relating to the calibrating details and to the International

Practical Temperature Scale of 1968.

Each thermometer is a solid-stem, mercury -in-glass instrument 180 ± 5 mm in length, and marked

with a 95 mm immersion line. The stems are plain front, enameled back made of lead-glass ther- mometer tubing 7 mm in diameter. Nitrogen gas fills the space above the mercury. Each thermometer has an auxiliary scale from -0.20 to + 0.20 °C with 0.05 °C divisions. The main scales of the

thermometers are 24.00 to 26.00 °C, 29.00 to 31.00 °C, and 36.00 to 38.00 °C, respectively, with

0.05 °C divisions. Calibrated points are 0 °C, and 25, 30, or 37 °C depending on the scale of the

individual thermometer. Detailed descriptions and drawings of these thermometers are given in the

following publications:

Mangum, B. W., Clin. Chem. 20, 670 (1974).

Mangum, B. W., and Wise, J. A., NBS Special Publication 260-48, U. S. Government Printing

Office, Washington, D.C. 20402, 1974.

The thermometers were manufactured by Prineo Instruments, Inc. of Southampton. Pa. Measurements leading to the certification were performed by J. A. Wise of the Meat Division, Institute for

Basic Standards.

The general direction of the technical work was performed by B. W. Mangum of the Heat

Division, Institute for Basic Standards.

Washington, D.C. 20234 J. Paul Cali, Chief

October 1, 1974 Office of Standard Reference Materials

101
S. Department of Commerce

Frederick B. Dent

Secretary

National Bureau of Standards

Richard W. Roberta, Director

^National ££uram of j^tandard*

Certificate

Standard Reference Material 934

Clinical Laboratory Thermometer

This Standard Reference Material is intended for use in clinical laboratories as a primary

calibrant, particularly in the area of clinical enzymology. The thermometer is individually calibrated

at four points. The certified corrections, as a computer print-out sheet, are attached, together with

information relating to the calibration details and to the International Practical Temperature Scale

of 1968.

The thermometer is a solid-stem, mercury-in-glass instrument 300 ± 5 mm in length, and marked

with a 95-mm immersion line. The stem is plain front, enameled back, made of lead-glass

thermometric tubing 7 mm in diameter. Nitrogen gas fills the space above the mercury. It has an

auxiliary scale from-0.20 to +0.20 °C with 0.05 °C divisions. The main scale extends from 24.00

°C to 38.00 °C in 0.05 °C divisions. The calibrated points are 0, 25, 30, and 37 °C. Detailed

description and drawings of the thermometer are given in the following publications:

Mangum, B. W., Clin. Chem. 20, 670 (1974).

Mangum, B. W., and Wise, J. A., NBS Special Publication 260-48, U. S. Government Printing

Office. Washington, D. C. 20402, 1974.

The thermometers were manufactured by Princo Instruments Inc., of Southampton, Pa.

Measurements leading to the certification were performed by J. A. Wise of the Heat Division,

Institute for Basic Standards.

The general direction of the technical work was performed by B. W. Mangum of the Heat

Division, Institute for Basic Standards.

Washington, D.C. 20234 J. Paul Cali, Chief

October 23, 1974 Office of Standard Reference Materials

102
U.S. Department of Commerce

Juanita M. Kreps

Secretary

National Buremj of Standards

Ernest Ambler, Acting Director

^National ^nttnn of j^tatutartb

(Certificate

Standard Reference Material 935

Crystalline Potassium Dichromate

for Use as an Ultraviolet Absorbance Standard

R. W. Burke and R. Mavrodineanu

This Standard Reference Material consists of crystalline potassium dichromate of established purity. Solutions

of known concentrations of this SRM in 0.001 N perchloric acid are certified for their apparent* specific

absorbances**, €a , at 23.5 °C.

This SRM is intended to be used as a reference standard for the verification of the accuracy and linearity of the absorbance scale of absorption spectrometers that can provide an effective spectral bandpass of 1.2 nm or less

at 235 nm, and 0.8 nm or less at 257, 3 1 3, 345, and 350 nm. Such verification is accomplished by comparing the measured apparent absorbances, Aa , to the Aa calculated from the certified €a values as described under

"Instructions for Use."

Table 1 gives the certified values of 6a in kgg ' cm

1 for five concentrations of the SRM 935 potassium

dichromate in 0.001 N perchloric acid at 23.5 °C and the indicated wavelengths and spectral bandpasses for a 1-cm internal pathlength.

a —j — | Table 1. €a . Apparent Specific Absorbance, kg g cm

Nominal Wavelength and (Bandpass) nm

Concentration

g-kg"' 235.0(1.2) 257.0(0.8) 313.0(0.8) 345.0(0.8)" 350.0(0.8) Uncertaii

0.020 12.260 14.262 4.805 10.604 10.672 ± 0.034

.040 12.304 14.318 4.811 10.603 10.682 ± .020

d

.060 12.347 14.374 4.816 10.602 10.692 ± .020

d

.080 12.390 14.430 4.821 10.601 10.701 ± .020

d

.100 12.434 14.486 4.827 10.600 10.711 ± .020

d

a Ca values are given to the third decimal place to preserve the smooth variation of the data with concentration, although the

uncertainties are in the second decimal place. Wavelength 345.0 nm is near one of the two isosbestic points in HCrOJ/C^O? spectra. Because it is on the slope of the composite

spectrum, reproduction of the Ca values is dependent on wavelength accuracy. Measurements at this wavelength should be made only for

verification of the linearity of the absorbance scale. 6a values are not corrected for the effects of internal multiple reflections within the cuvette, nor have the weights been corrected to vacuum. With these two exceptions, the uncertainties given include all known systematic errors and the 95 percent confidence

interval of the mean. At wavelength 313.0 nm, the uncertainty is reduced to ±0.010.

•The term "apparent" is used because no corrections have been applied to the data for the effects of internal multiple reflections within the

cuvette or for buoyancy, i.e., the weights used to express concentrations have not been corrected to vacuum. These combined corrections do not exceed 0.2 percent. The specific absorbances are given in reference 1. "The nomenclature used in this certificate is that recommended by K. D. Mielenz, Anal. Chem.48, 1093-1094(1976), which is reproduced

in the Appendix of NBS Special Publication 260-54.

Washington, D.C. 20234 J. Paul Cali, Chief

June 1, 1977 Office of Standard Reference Materials

(over)

103
The overall direction and coordination of the technical measurements leading to this certificate were per- formed under the joint chairmanship of I. L. Barnes and J. R. DeVoe.

The technical and support aspects involved in the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by R. W. Seward.

We wish to acknowledge: The contributions of K. D. Mielenz, NBS Analytical Chemistry Division, for his many

valuable discussions and suggestions, and H. H. Ku, NBS Applied Mathematics Division, for his statistical treatment of the data; the cooperation and early support of the National Institute of General Medical Sciences in the research leading to this SRM; and the encouragement of George N. Bowers, Jr., M.D., Hartford Hospital,

Hartford, Conn., and Royden N. Rand, Ph.D., Eastman Kodak Co., Research Laboratories, Rochester, N.Y.

PREPARATION AND CERTIFICATION

The details of the preparation and certification of SRM 935 are provided in NBS Special Publication 260-54,

Certification and Use of Acidic Potassium Dichromate Solutions as an Ultraviolet Absorbance Standard [2]. This publication should be referred to every time SRM 935 is to be used. Briefly, the transmittances, T, of the solutions prepared from the undried, as received, material were measured with the NBS Institute for Materials

Research high-accuracy transmission spectrometer [3].

The €a values were calculated for each wavelength using the relation:

where:

(1)

6a — apparent specific absorbance

Aa = apparent absorbance

Ds = transmittance density of the sample solution, -logioTs Db= transmittance density of the blank solution, -logioTb

b = internal cuvette pathlength, cm

c = concentration, by weight, of K.2Cr207 solution, gkg 1

The crystalline potassium dichromate used for SRM 935 is a special lot of analytical reagent grade material

obtained from the J. T. Baker Chemical Co., Phillipsburg, N.J.

Assay: A coulometric assay of the purity of the undried material was performed by G. Marinenko of the NBS

Analytical Chemistry Division. The purity of SRM 935, expressed as an oxidant, was found to be 99.972 ± 0.005

percent where the uncertainty figure represents the 95 percent confidence interval for the mean based on 1

1

degrees of freedom. In addition, the material was examind by optical emission spectrometry for trace elemental

impurities by J. A. Norris of the NBS Analytical Chemistry Division. The only significant impurities detected were sodium and rubidium. Their concentrations were estimated to be in the range of 0.02 and 0.03 percent,

respectively. Drying at 105 °C for 12 hours showed that the surface moisture of this material was less than

0.01 percent.

Stability: Solutions prepared from SRM 935 in the concentration range indicated in table 1 and made according

to the instructions given in NBS SP 260-54 have been found to be stable within the uncertainties given in table 1

for at least six months when stored at room temperature and protected from evaporation and exposure to light.

INSTRUCTIONS FOR USE

The use of SRM 935 as an absorbance standard requires the careful preparation of a series of solutions of

known concentrations, c, of the potassium dichromate in 0.001 N perchloric acid. These solutions are trans- ferred to a quartz cuvette of known pathlength, b, and their apparent absorbances measured at wavelengths

235, 257, 313, and 350 nm, using the spectral bandpass requirements given in table 1. The preparation and

measurement of these solutions are described in detail in Section 5 of NBS SP 260-54.

104
The accuracy of the absorbance scale of the spectrometer being tested is ascertained by comparing the measured

apparent absorbances, Aa, of a series of 0.001 N perchloric acid solutions containing 0.020 to 0.100 gram

K2Cr207 / kg to the Aa values calculated from the certified €a values. Although the €a data in table 1 are given for nominal concentrations of 0.020, 0.040, 0.060, 0.080, and 0. 100 g K2Cr207/kg, the €a values for concentrations

between these nominal concentrations can be determined by linear interpolation. Using the appropriate €a values, the calculated Aa values at 23.5 °C are obtained from the expression:

Aa = €a x b x c (2)

Calculations:

An example of the calculation of Aa for one concentration of K2Cr2C>7 under a specified set of conditions is shown below. Calculations of Aa for other concentrations and wavelengths are performed in a similar manner.

Conditions: Wavelength = 350 nm, spectral bandpass 0.8 nm or less b = 0.9982 cm

c = 0.04375 gkg 1

t = 23.5 °C

From column 6, table 1, the €a for concentrations of 0.040 and 0.060 g kg

1 are 10.682 and 10.692, respectively.

The corresponding €a for c = 0.04375 g kg is:

ea =10.682 + ^-°

047 (10.692 -10.682)

6a = 10.682 + 0.0019

€a = 10.684

The calculated apparent absorbance, Aa , from equation 2, is: Aa = 10.684 x 0.9982 x 0.04375

Aa = 0.4666

The uncertainty, AAa, in the calculated Aa is determined from the combined uncertainties in €a , b, and c in equation 2, provided no other systematic errors are present. Thus:

AAa = be | A€a | + €ac | Ab | + €a b | Ac | (3) To evaluate AAa , A€a is taken from column 7 of table 1 and the Ab and Ac values must be determined experimentally.

In the experiments performed to obtain the €a values in table 1 , the uncertainties for b and c did not exceed 1 part

in 10 and 2 parts in 10 , respectively.

The solution of equation 3 gives:

AAa = 1(0.044) (0.020) + 10.7(0.044) (0.0001) + 10.7(1) (0.0000088) = 0.0010

Thus, the uncertainty of Aa, for the above set of conditions, is ±0.0010.

The correction of the absorbance scale of the absorption spectrometer under test is determined by plotting the

differences between Aa measured and Aa calculated as a function of absorbance. A typical plot of such a graph

is shown in figure 1. The apparent absorbances measured on this instrument at 350 nm are accurate when the indicated correction is subtracted from the corresponding absorbance scale reading, provided that the conditions of wavelength accuracy, spectral bandpass, and absence of stray light are fulfilled as specified in NBS SP 260-54. Correction curves for wavelengths 235, 257, and 313 nm are obtained in a similar manner.

105
Figure 1. Correction curve for the absorbance

scale of a precision spectrometer. The error bars

are the sum of the errors arising from the uncertainties in the certified apparent specific absorbances,

€a , cuvette pathlength, b, and concentration, c.

o I—i U,—i i i i i i i

i i 0 0.2 0.4 0.6 0.8 1.0

Absorbance

Temperature Correction:

Although €a values in table 1 are certified at 23.5 °C, SRM 935 can be used as an absorbance standard at other

temperatures in the range 20 to 30 °C provided corrections are made to the €a values. Over this range the apparent specific absorbances decrease linearly with increasing temperature for all the wavelengths given in table 1. The corresponding temperature coefficients, k, for these wavelengths are given in table 2.

Table 2. Variation of €a with Temperature Over the Range 20 to 30 °C.

A, nm Temperature Coefficient, k

Percent per degree Celsius

235 -0.05

257 -0.05

313 -0.02

345 -0.08

350 -0.05

The value of €a at any temperature in the range 20 to 30 °C can be calculated from the certified value and the appropriate temperature coefficient using the relation:

€a = ea23 5 £l +~(t-23.5)J

where: Ca = apparent specific absorbance at temperature t (°C)

23 5 €a = apparent specific absorbance certified at 23.5 °C.

k = temperature coefficient, percent per °C.

REFERENCES

1. Burke, R. W., and Mavrodineanu, R., Acidic Potassium Dichromate Solutions as Ultraviolet Absorbance

Standards, J. Res. Nat. Bur. Stand. (U.S.), 80A (Phys. and Chem.), No. 4, 631-636 (July-Aug. 1976).

2. Burke, R. W., and Mavrodineanu, R., Certification and Use of Acidic Potassium Dichromate Solutions as an Ultraviolet Absorbance Standard, NBS Spec. Publ. 260-54 (1977). Copies may be obtained from the

Office of Standard Reference Materials, National Bureau of Standards, Washington, D.C. 20234.

3. Mavrodineanu, R., An Accurate Spectrophotometer for Measuring the Transmittance of Solid and Liquid

Materials, J. Res. Nat. Bur. Stand. (U.S.), 76A (Phys. and Chem.), No. 5, 405^25 (1972).

106
U.S. Department of Commerce

Juanita M~ Kreps

National Bureai? or Standards

Ernest Ambler, pirector

Rational ^mtnn of js»tandard*

(Eerttfttate

Standard Reference Material 936

Quinine Sulfate Dihydrate

R. A. Velapoldi and K. D. Mielenz

ITiis Standard Reference Material is intended for use in the evaluation of methods and the calibration of

fluorescence spectrometers. It is certified for the relative molecular emission spectrum, E(X), in radiometric

units for a solution of 1.28 x 10 mol/L quinine sulfate dihydrate in 0.10S mol/L perchloric acid using an

excitation wavelength of 347.5 nm. The certified values of the molecular emission spectrum at 5 nm wavelength intervals from 375 to 675 nm are given in table 1 . These values have been corrected for instrument and

sample parameters, including the spectral responsivity of the detection system, monochromator bandwidth,

photomultiplier tube nonlinearity, monochromator wavelength error, solvent refractive index, and cell window

transmittance. The relative standard error in E(X), RSE [E(X)], is given in table 1. The estimate of the

relative systematic error limits in the molecular emission spectrum, RSEL [E(X)], is also given in table 1 and

was determined by the addition of the absolute values of the estimated systematic errors. These relative error

limits include uncertainties in the calibration values for the spectral responsivity, the wavelength position of the emission peak maximum, and in the corrections applied for instrument and sample parameters.

From the certified values of E(X), values may be calculated for the molecular emission spectrum in the various

photon, radiometric, wavelength, and wavenumber units using the following equation: [1,2]

E(X) =

EP(X) E(tT) EP (5T)

X

2 X

3

These values have been calculated and are given in NBS Special Publication 260-64.

The technical emission spectrum, E

T

(X), i.e., the emission spectrum corrected for instrument parameters only,

is also given in SP 260-64. The quinine sulfate dihydrate used for SRM 936 was a special lot of material

obtained from the J. T. Baker Chemical Co., Phillipsburg, N.J.

The technical and support aspects concerning the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by T. W. Mears and

R. W. Seward.

Washington, D.C. 20234 George A. Uriano, Chief

April 1, 1979 Office of Standard Reference Materials

(over)

107
Table 1. The Molecular Emission Spectrum, E(X), of Quinine Sulfate Dihydrate in 0.105 mol/L HCIO4, the

Relative Standard Error, RSE, and the Estimated Relative Systematic Error Limits, RSEL, in the

E(X) Values.

X,nm E(X) RSE [E(X)] RSEL [E(X)]

375.0 0.005 0.019 0.087

380.0 .012 .006 .078 385.0 .028 .003 .071 390.0 .057 .003 .064 395.0 .103 .002 .059 400.0 .170 .002 .054

405.0 .257 .003 .049

410.0 .359 .003 .045 415.0 .471 .003 .041 420.0 .586 .003 .037

425.0 .694 .003 .034

430.0 .792 .002 .031 435.0 .874 .002 .028 440.0 .940 .001 .026 445.0 .984 .001 .024 450.0 .999 .001 .023 455.0 .997 .001 .023 460.0 .982 .001 .024 465.0 .947 .001 .024

470.0 .897 .001 .025

475.0 .838 .002 .026

480.0 .782 .002 .027 485.0 .719 .002 .027 490.0 .657 .002 .027 495.0 .595 .003 .027 500.0 .541 .002 .027 505.0 .486 .001 .028 510.0 .434 .003 .028 515.0 .386 .003 .028 520.0 .342 .002 .028

SRM 936

Page 2

X,nm E(X) RSE [E(X)] RSEL [E(X)]

525.0 0.302 0.001 0.029

530.0 .264 .003 .029 535.0 .231 .003 .029 540.0 .201 .002 .029 545.0 .175 .002 .029 550.0 .153 .001 .029 555.0 .132 .001 .029 560.0 .116 .001 .029 565.0 .101 .002 .029 570.0 .088 .002 .029

575.0 .076 .003 .029 580.0 .065 .003 .029 585.0 .057 .001 .029 590.0 .050 .003 .030 595.0 .043 .004 .030 600.0 .037 .006 .030 605.0 .032 .002 .030 610.0 .028 .006 .030

615.0 .024 .003 .030

620.0 .021 .011 .030

625.0 .018 .003 .030 630.0 .016 .015 .030

635.0 .014 .014 .030

640.0 .011 .037 .030 645.0 .010 .015 .030 650.0 .009 .027 .030 655.0 .008 .035 .031 660.0 .007 .073 .031 665.0 .006 .046 .032 670.0 .005 .053 .032 675.0 .004 .065 .033

108
SUPPLEMENTARY DATA

The following data for the specific molar absorbances, water content, photon yields, and fluorescence lifetimes are considered to be supplementary and are not to be considered certified values.

The quinine sulfate dihydrate (QSD) used for SRM 936 was found to be homogeneous to better than 0.5% by

thin-layer chromatography with development by two solvent systems and the determination of specific molar

absorbances, €, at three different wavelengths. The SRM contains approximately 1.7% of an impurity as determined by high performance liquid chromatography using absorbance and fluorescence detection. This

impurity is believed to be dihydroquinine sulfate dihydrate, which has optical characteristics that are similar to those of the quinine sulfate dihydrate. The ultraviolet absorption spectrum of SRM 936 in 0. 105mol/L HCIO4

exhibits the following absorption maxima:

250.0 nm, emax = 56,990 ± 90 Lmof'cnf 1

347.5 nm, emax = 10,810 ± 20 L mof' cnf1

and, on the side of a peak:

365.0 nm, €obs = 6,920 ± 10 Lmof'cm"'

The water content of this material was measured by two methods. The average of six determinations by the Karl-Fischer method gave a value of (4.74 ± 0.05%), while the average of four determinations by a weight loss procedure gave a value of (4.57 ± 0.04%). The theoretical value for water in quinine sulfate dihydrate is 4.60%.

The photon yield, Q, and the fluorescence lifetime, t, of SRM 936 were compared to values obtained for a sample of purified quinine sulfate dihydrate and are summarized below:

Q r, ns

0.5 mol/L H2SO4 0.5 mol/L H2SO4

SRM 936, QSD 0.544 ± 0.03 19. 1 ± 0.

1

Purified QSD 0.546

a 19.2 ± 0.1

a Melhuish, W. H., J. Phys. Chem. 65, 229 (1961); ibid, New Zealand J. Sci. Tech. 37, 142

(1955).

SRM 936

Page 3

(over)

109
PREPARATION AND USE OF SRM 936

This Standard Reference Material is for "in vitro" diagnostic use as a clinical laboratory standard. A "stock"

standard solution containing 0. 1 mg/mL of quinine sulfate may be prepared as follows: Weigh 0. 100 g of SRM

936 to the nearest one-tenth milligram and quantitatively transfer it to a 1000-mL volumetric flask. Dilute to the

calibrated volume withO. 105 mol/L HC104,to give a solution that is 1.28 x 10 mol/L(0. 1 mg/mL) in quinine

sulfate. Store this solution in the dark in a well-stoppered, glass bottle. A "working" standard solution

containing 1 fxg/mL may be prepared by transferring 10 mL of the above "stock" standard solution to a 1000-mL volumetric flask and diluting to the calibrated volume with 0. 105 mol/LHC104 to give a solution that

is 1.28 x 10 mol/L (1 ng/mL) in quinine sulfate. Store this solution in the same manner as the above "stock"

standard solution.

Several opinions regarding the stability of quinine sulfate solutions have appeared in the literature [3]. NBS

considers the 0. 1 mg/mL "stock" standard solution prepared from SRM 936 to be stable for 3 months when

stored as specified; and the 1 vg/mL "working" standard solution to be stable for 1 month when so stored. SRM 936 should be kept in its original bottle and stored in the dark at room temperature (30 °C or less). It should not be subjected to heat or direct sunlight during storage. Experience at NBS indicates that under proper

storage this material is stable for at least 3 years. If this material degrades beyond the limits certified, purchasers

will be notified by NBS. It is recommended that the material not be used after 3 years from the date of purchase.

References:

[1] Ejder, E. J., J. Opt. Soc. Amer. 59, 223 (1969).

[2] Melhuish, W. H., J. Res. Nat. Bur. Stand. (U.S.) 76A, No. 6, 547 (1972).

[3] Melhuish, W. H., J. Phys. Chem. 65, 229 (1961); Gill, J. E., Photochem. and Photobiol. 9, 313(1969); Birks,

J. B., J. Res. Nat. Bur. Stand. (U.S.) 80A, 389 (1976); Heller, C. A., Henry, R. A., McLaughlin, B. A., and

Bless, D. E., J. Chem. Eng. Data 19, 214 ( 1974); West, M. A., and Kemp, D. R., Int'l. Lab., p. 27 (May/ June

1976); and White, J. U., Pittsburgh Conf. Abstracts, Paper 488 (1977).

This Standard Reference Material has been measured and certified at the laboratories of the National Bureau

of Standards, Gaithersburg, Maryland. All inquiries should be addressed to:

Office of Standard Reference Materials

Room B31 1, Chemistry Building

National Bureau of Standards

Washington, D.C. 20234

The date of issuance and certification of SRM 936 was April I, 1979

SRM 936

Page 4

110
U.S. Department of Commerce

Juanita M. Kreps

National Bureau ofStandards Emnt limber. Director

Rational £3uram of J^tanttartte

Certificate of ^nalgsi*

Standard Reference Material 937

Iron Metal

(Clinical Standard)

This Standard Reference Material is certified as a material of known purity for use as an assay standard for iron.

It is intended primarily for the calibration of instrumentation and standardization of procedures employed in

clinical analysis and for the routine evaluation of daily working standards used in these procedures.

Assay 99.90 ± 0.02 percent by weight

The assay shown is based on dissolution of representative samples in hydrochloric acid followed by reduction of

the iron with stannous chloride and oxidation of the excess stannous chloride with mercuric chloride. Most of

the iron was oxidized with a known weight of potassium dichromate and the remaining iron was titrated with

potassium dichromate solution. The estimated uncertainty shown is based on judgment and includes allow- ances for known sources of possible error. SRM 937 is electrolytic grade iron. Chemical analyses made on representative samples showed the presence of

the following elements at the indicated concentrations in percent by weight: nickel, 0.041%; silicon, 0.008%;

carbon, chromium, and cobalt, each 0.007%; copper, manganese, oxygen, and sulfur, each 0.006%; molybdenum, 0.005%; phosphorous, 0.003%; germanium and nitrogen, each 0.001%; with the total of all other

elements <0.003%.

The iron content, by difference, is 99.89+%, which is in agreement with the assay value.

The chemical assay was performed by B. I. Diamondstone; the elemental determinations by R. Alvarez, J. R. Baldwin, E. Belkas, B. S. Carpenter, M. M. Darr, E. R. Deardorff, T. E. Gills, L. A. Machlan, E. J. Maienthal,

L. J. Moore, C. W. Mueller, T. J. Murphy, P. J. Paulsen, K. M.Sappenfield, B. A. Thompson, and S. A. Wicks.

The overall direction and coordination of the technical measurements leading to certification were under the

chairmanship of I. L. Barnes.

The technical and support aspects concerning preparation, certification, and issuance of this Standard Refer- ence Material were coordinated through the Office of Standard Reference Materials by R. Alvarez.

Washington, D.C. 20234 J. P. Cali, Chief

June 9, 1978 Office of Standard Reference Materials

(over)

111
This Standard Reference Material is intended for "in vitro" diagnostic use only.

This material is intended for use as a standard for iron determination in clinical chemistry.

Preparation of stock iron standard solution (0.02 mmol/mL)

Weigh approximately 1 g of SRM 937 to the nearest 0. 1 mg and transfer it to a one-liter volumetric flask. Dissolve the metal in 100 mL of 6 mol/L HC1 and dilute to one liter with water

The exact concentration of this stock solution, in mmol/mL, is expressed by:

mg (SRM 937) X 0.999

55.847 X 1000

Preparation of working stock iron standard solution (0.2 jumol/mL)

Transfer 10 mL of the stock iron standard solution to a one-liter volumetric flask and add 0.2 mol/L HC 1 to the graduation line.

Preparation of working iron standard solutions

Prepare more dilute solutions by pipetting known volumes of the working stock iron standard solution into

volumetric flasks and diluting to the graduation line with 0.2 mol/L HC1. These solutions should be prepared

daily. [Note: In the preparation of very dilute solutions, the 0.2 mol/L HC1 may contain sufficient iron, as an

impurity, to affect the calculated iron concentrations of these dilute solutions.]

Precautions: All volumetric glassware used should conform to the specifications for Class A glassware and, for highest accuracy, should be individually calibrated and used at the calibration temperature [1]. All glassware

should be cleaned in hot dilute HC1 and rinsed in distilled water.

This SRM should be stored in the tightly closed original bottle under normal laboratory conditions.

Reference:

[1] J. Lembeck, The calibration of small volumetric laboratory glassware, NBSIR 74-461, National Bureau of

Standards, Washington, D.C. 20234.

The date of issuance and certification of this Standard Reference Material was June 9, 1978.

112
U.S. Department of Commerce

Juanita M. Kreps

Secjetory

National Bu«?eu of Standards

Ernest Ambler, Acting Director Rational ££ttram of j^tantlartte

(Certificate

Standard Reference Material 1968

Gallium

Melting-Point Standard

Cell No.

29.7723 ± 0.0007 °C

International Practical Temperature Scale of 1968

This Standard Reference Material is intended to be used to calibrate thermometers near 30 °C. SRM 1968

consists of approximately 25 grams of high-purity gallium in a specially designed, epoxy-sealed cell. The

melting-point temperature of this cell, as given above, was verified using a set of three stable thermistors that were regularly recalibrated against a Standard Platinum Resistance Thermometer. The Standard Platinum

Resistance Thermometer, which was recently calibrated on IPTS-68 at NBS, was used in the determination of

the gallium triple-point temperature at NBS. The stated uncertainty, ±0.0007 °C, represents one-half of the

total range of the temperatures observed in 152 determinations of the melting points of this and similar cells. SRM 1968 can be used to calibrate all thermometers that have temperature sensing elements smaller than

3.5 mm in diameter. With care, such thermometers may be calibrated with an accuracy of ±0.0007 °C. The

liquid-solid equilibrium temperature of pure gallium at a pressure of one standard atmosphere (101.3 kPa) is 29.7723 ± 0.0004 °C [1]. This equilibrium is best realized by slowly melting the solid.

The high-purity gallium metal used in SRM 1968 was obtained from Eagle-Picher Industries, Inc., Quapaw,

Oklahoma.

The technical measurements at NBS leading to certification were performed by D. D. Thornton and B. W.

Mangum of the NBS Heat Division.

The technical and support aspects involved in the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by R. W. Seward.

Washington, DC. 20234 J. Paul Cali, Chief

June 1977 Office of Standard Reference Materials

(over)

113
SRM 1968 was designed by D. D. Thornton of theNBS Heat Division. The cell components were fabricated by

the NBS Instrument Shops Division. The cell consists of a Teflon body, a nylon well, and a nylon cap stem, as shown in figure I. Filling, assembling, and sealing of the cells were performed in a dry argon atmosphere.

NYLON

TEFLON

1.27 cm ID

1.47 cm OD

0.36 cm ID

Fig. 1. Cross-sectional drawing of SRM 1968, Gallium MeltingPoint Standard.

CAUTION: Because the nylon parts of the cell will absorb waier, the cell should not be immersed in water for periods exceeding two days. Particular care should be exercised to prevent water entering the cap stem and well. When the cell is immersed in water, at least one centimeter of the cap stem should protrude from the surface. NOTE: The gallium in SRM 1968 was frozen before leaving NBS. If the metal should melt completely, it should

refreeze readily in an ambient of 20 °C. Should the metal supercool and remain liquid at room temperature,

solidification can be induced by placing the cell in an ice bath or freezer for about two hours.

Instructions for Use of SRM 1968

SRM 1968 should be used as a calibrant in a temperature-regulated bath. To calibrate a thermometer with SRM

1968, the user should employ a light mineral oil for thermal contact in the well. Any water should be removed

from the sensor before inserting it into the well. The temperature sensing element should be inserted into the

well and the cell then inserted into the bath, which has been regulated to a temperature of 30.0 ±0. 1 °C. Within

30 to 60 minutes, the thermometer should indicate a steady reading, which corresponds to the gallium melting

point (29.7723 °C).The duration of the melting plateau depends on the bath temperature (figure 2) Thus, once

melting has begun, the duration of the plateau can be prolonged by setting the bath to 29.80 ± 0.03 °C—just

above the gallium melting point. The bath temperature can be checked by temporarily placing the thermometer

sensor directly into the bath.

114
v>

29.760 -

29.7501 I I I I I 1 1 L

0 1 2 3 4 5 6 7 0 HEATING TIME (HOURS)

Fig. 2. Melting curves of SRM 1968 (nominal 99.99999% pure

gallium) for several different temperature gradients.

Accuracy of Calibration

The melting temperature of the gallium is very accurately known; however, several factors introduce uncertainty, and thus reduce the accuracy of the calibration. The most likely limiting factor in the accuracy of the

calibration is the scale (or read-out) of the thermometer being calibrated. For example, a thermometer with a

digital read-out to the nearest 0.01 °C will read all temperatures from 29.765 to 29.774 °C as 29.77 °C. For

thermometers with resistive sensing elements (e.g., thermistors), another limiting factor is the self-heating

caused by the current through the element. The size of the self-heating effect depends upon the local environment of the sensing element, and will introduce an uncertainty into the calibration. The instruction manual for the thermometer should be consulted, both in this regard and in reference to the resolution problem mentioned

above.

The immersion effect is yet another potential source of calibration error. In the presence of a temperature dif- ference (AT) between the bath and the sensor, heat will be conducted along the leads to or from the sensor and

will produce an immersion error (ST). When the thermometer is sufficiently immersed, most of the heat con- ducted along the leads is transferred through the insulation and the immersion error, ST, is insignificant. Because the error, ST, depends on AT, any significant immersion error can be minimized. The extent of such a problem can be determined when calibrating a thermometer with SRM 1968 in a bath at 30.0 °C. Set the bath

temperature to 3 1 .0 ° C and observe the thermometer in the gallium cell for 1 5 minutes. When a new steady value

is reached, the difference (ST) between this value and the value obtained with the bath at 30.0 ° C is a measure of

the immersion effect. For example, if the thermometer showed a change of 0.02 °C when the bath temperature was increased by 1 °C, then the immersion effect is 0.02 °C per degree Celsius. This example implies that the bath must be set no higher than about 29.9 °C if the immersion error is to be less than 0.003 °C.

[1] Mangum, B. W., and Thornton, D. D., Determination of the Triple-Point Temperature of Gallium (to be

published).

[2] Thornton, D. D., The Gallium Melting-Point Standards: A Determination of the Liquid-Solid Equilibrium

Temperature of Pure Gallium on the International Practical Temperature Scale of 1968, Clinical Chemistry

23, No. 4, 719-724 (April 1977).

115
U.S. Department of Commerce

Juanita M. Kreps

Secretary

National Bureau of Standard*

Ernest Ambler. Director

^National ^Suram of £&tnndntdz

Olerttftcat^

Standard Reference Material 2009

Didymium Glass Filter for Checking the

Wavelength Scale of Spectrophotometers

Kenneth L. Eckerle and William H. Venable, Jr.

Serial Number:

This SRM is intended for use in calibrating the wavelength scale in the visible wavelength region of scanning

spectrophotometers having nominal bandwidths in the range 1.5 to 10.5 nm. Depending upon the bandwidth of

the spectrophotometer, anywhere from 14 to 24 wavelength corrections can be determined from 400 to 760 nm.

Detailed instructions on the use of this SRM and examples of its use are given in NBS Special Publication

260-66. Each didymium-glass filter is identified by the SRM number and a serial number.

The wavelengths of the transmittance minima as obtained from measurements on two filters representative of

the melt are given in Table 1 . These values are given for seven equally spaced values of the half-height width of

triangular passbands. The minima number is identified in the figure that illustrates the spectral transmittance as

a function of wavelength. The wavelength values of nine points of inflection on the spectral transmittance curve

as obtained on two filters are given in Table 2. These inflection points are representative of the melt and are also

identified in the figure. These inflection points should only be used with the transmittance minima as described

in Sections 2.2 and 2.3 in SP 260-66.

The measurements on which these tables are based were made at 25 °C with a high-precision reference spectrophotometer that has a wavelength accuracy of 0.04 nm. Table 3 indicates the estimated random (as obtained

from 4 sets of measurements on a single filter) and systematic errors of the transmittance minima given in Table

1 . Table 2 also indicates the range of the measured wavelengths of the inflection points. Trial calibrations made

on several instruments, using both minima and inflection points, indicate that wavelength corrections made with

these SRM's can be accurate to 0.2 nm. The uncertainty of a calibration, however, will depend upon the stability

and other characteristics of a particular instrument.

The technical and support aspects involved in the preparation, certification, and issuance of this SRM were

coordinated through the Office of Standard Reference Materials by R. K. Kirby.

The spectral transmittance as a function of wavelength for a filter representative of the melt is given in Table 4. These values are not certified but are provided for use as specified in SP 260-66. They should not be used to check

the photometric scale of a spectrophotometer.

It is recommended that the filter be handled only by its edges and when not in use it should be stored in the box

provided. If cleaning is necessary, wet the filter with water and rub gently with optical lens tissue soaked with a

mild soap solution, rinse with distilled water, rinse with isoprophyl alcohol, and rinse again with distilled water. Dry after each rinsing by wiping lightly with optical lens tissue.

Washington, D.C. 20234 George A. Uriano, Chief

January 8, 1980 (over) Office of Standard Reference Materials

116
Wavelength (nm)

Spectral transmi ttance of a typical didymium glass filter. Numbers

indicate the principal points of minimum transmittance and letters

indicate the principal points of inflection.

SRM 2009 117
Table I

Certified Wavelengths (nm) of the Transmittance

Minima for the Indicated Bandwidths

iHu/iHth IU vv IU 111 mum No.

1 .5 nm 1 0 nmmil 4.5 nm 6.0 nm 7.5 nm 7.U Mill inI U.JS 11II1 nm

I 402.42 401.81 401.69 401.66 401.42 400.95

2 431.50 432.48

3 440.27 440.52 441.84 442.52 442.37 442.08 441.33

4 445.59 445.14

5 472.72 472.58 472.88

6 478.89 479.34 479.28 478.31 477.36 476.50 475.65

7 513.45 513.61 513.89 514.31 515.38

8 529.58 530.02 529.90 529.47 529.27 529.12 528.88

9 572.69 573.27 574.21 575.11 576.59

10 585.34 585.54 585.77 586.02 585.99 585.35 584.42

II 623.62 624.02

12 629.53 629.41 628.56 627.03 627.02

13 684.66 684.68 684.71 684.72 684.71 684.66 684.58

14 739.86 739.96 740.24 740.91 742.01 742.97 743.65

15 748.28 748.10

Table 2

Wavelengths and Transmittances at Nine Selected

Points of Inflection

SRM 2009

Point Wavelength Range* Transmittance^"

Identification (nm) (nm)

A 406.44 +.08 0.7760

-.06

B 429.43 +.05 .7359

-.05

C 449.49 +.06 .6516

-.06

D 484.84 +.10 .6758

-.15

E 536.50 +.06 .5805 -.09

F 568.15 +.08 .4023 -.04

G 599.05 +.05 .3348

-.07

H 733.39 +.06 .4719

-.03

I 756.45 +.01 .4177

-.02

*The range of wavelengths within which the wavelength for the given trans- mittance will fall for symmetric triangular passbands with half-height bandwidths from 1.5 to 10.5 nm.

^These values of transmittance are not certified. 118
Table 3

Estimated Random and Systematic Errors of the Transmittance Minima

Band Nominal Standard Deviation for Indicated Bandwidth Number Wavelength

of Minimum 1.5 nm 3.0 nm 4.5 nm 6.0 nm 7.5 nm 9.0 run 10.5 nm

Transmittance

I 402 nm (0 07)t"m

0.018 nm 0.020 nm 0.021 nm 0.025 nm 0.029 nm

iS' 00,0 ----- 3 440

(0 05) 0013 0 050 0 028 0 009 0 005

(0 25) nm

4 446 (OM) 0 029 ----- 5 473 «2JJ

0.0.2 0.032 -

6 479 0.013 0.009 0.009 0.009 0.014

0 02?

7 573 0.016 0.014 0.013 0.010

8 530 °°J

2

0.010 0.010 0.011 0.010 0.011 Mfl

0 004

9 573 "-^7 0.010 0.010 0.012 0.014

10 585 °

>0^

7 0.004 0.007 0.008 0.008 0.007 & »•<*' - - - -

12 630

(

°' 22° 0.120 0.171 0.133 0.091

13 685

(005)" 0 029 0 024 0 017 0 014 0 014

(0 25)

14 740

(°?^

9

0.013 0.011 0.010 0.009 0.009 ^

£2?

tValues in parentheses are estimates of the systematic

o-°'o

error. The estimates----- for the 1 .5 nm bandwidth were obtained from the data taken at

1 .5 nm intervals as compared to data taken at 0. 1 5 nm intervals. The method of estimating the systematic errors for the 10.5 nm bandwidth

is described in Section 3.4 in SP 260-66.

SRM 2009

119
TABLE 4

Transmittance (T) as a function of wavelength from 380 to 780.5 nm

for a bandwidth of 1.5 nm. The estimates of random and systematic

errors are also provided. These data are not certified.

Wave AT AT Wave AT AT

Length Standard System- Length Standard System

(nm) T Error atic (nm) T Error atic

380. 00 .61832 . 000054 . 00010 381. 50 .63896 . 000085 . 00010

383. 00 . 66210 . 000064 . 00010 384

.

50 . 68291 . 000079 .00010

386. 00 .70112 .000047 . 00010 387

.

50 .71885 .000071 . 00010

389. 00 .73590 . 000095 . 00010 390. 50 .74954 . 000040 .00010

392. 00 .76201 . 000083 . 00010 393

.

50 . 77104 . 000055 . 00010

395. 00 .77620 . 000064 . 00010 396

.

50 .77123 . 000038 .00010

398

.

00 .75013 . 000069 .00010 399

.

50 .72419 . 000079 . 00010

401. 00 . 70966 . 000070 . 00010 402

.

50 .69505 . 000071 . 00010

404. 00 .73683 .000057 .00010 405

.

50 .75886 . 000047 . 00010

407. 00 .77756 . 000088 . 00010 408 . 50 . 80673 . 000072 . 00010

410

.

00 . 82277 . 000058 . 00010 411

.

50 . 82813 . 000038 . 00010

413

.

00 .83115 . 000060 . 00010 414 . 50 .83287 . 000075 .00010

416 . 00 . 83222 . 000060 .00010 417 . 50 . 83200 . 000029 . 00010

419

.

00 .83277 . 000059 . 00010 420

.

50 .83844 . 000066 . 00010

422

.

00 .83711 . 000064 .00010 423 . 50 .83328 . 000052 . 00010

425

.

00 . 83511 . 000049 . 00010 426

.

50 .83414 . 000045 . 00010

428 . 00 .81620 . 000055 .00010 429

.

50 .72877 . 000023 . 00010

431

.

00 . 62212 . 000096 . 00010 432

.

50 .63478 . 000039 . 00010

434

.

00 .64183 . 000057 . 00010 435

.

50 .63392 . 000059 . 00010

437

.

00 .61858 . 000049 . 00010 438 . 50 .60090 . 000038 . 00010

440

.

00 . 59163 . 000064 .00010 441

.

50 . 59496 . 000053 . 00010

443

.

00 .60082 .• 000063 V W V V W .• 00010 V V V J- V 444 . 50 .59576 .000068 • \J v V-/ V v w . 00010

446

.

00 . 59315 . 000055 .00010 447 50 . 60769 . 000044 . 00010

449. 00 .63551 .000083 . 00010 450. 50 .66313 .000060 . 00010

452. 00 68002 \J KJ \J \J mm • 000069 U v w v/ v y • 00010 \J \J \J Jm \J 453 . 50 . 69110 000057 .00010

455. 00 .70206 . 000027 .00010 456. 50 .70341 .000033 . 00010

458. 00 .69051 . 000025 .00010 459. 50 .66807 .000049 . 00010

461. 00 .64890 .000057 .00010 462. 50 .63966 . 000060 .00010

464. 00 .63837 . 000070 .00010 465. 50 .63353 .000040 .00010

467. 00 . 62094 .000072 .00010 468. 50 .60572 .000053 .00010

470. 00 . 59042 .000008 .00010 471. 50 . 57213 . 000072 .00010

473. 00 . 56160 .000033 . 00010 474. 50 .58414 . 000031 .00010

476. 00 . 59528 . 000052 .00010 477. 50 . 56003 . 000052 .00010

479. 00 . 54953 . 000070 .00010 480. 50 .55659 .000036 .00010

482. 00 . 57326 . 000025 .00010 483. 50 . 62009 .000040 .00010

485. 00 .67764 .000052 . 00010 486. 50 .72126 .000072 .00010

488. 00 . 75412 . 000045 .00010 489. 50 .78321 . 000082 . 00010

491. 00 . 80556 . 000035 .00010 492. 50 .81759 . 000060 .00010

494. 00 . 82117 .000063 . 00010 495. 50 .81916 . 000038 .00010

497. 00 .81233 . 000096 .00010 498. 50 .80115 .000044 .00010

SRM 2009

120
TABLE 4 (cont)

Wave- AT AT

Length Standard System

(nm) T Error atic

500

.

00 .78689 . 000060 .00010

503

.

00 . 75433 . 000047 .00010

506

.

00 . 72185 . 000070 . 00010

509

.

00 .65070 .000060 . 00010

C T A 512

.

00 .53799 . 000044 . 00010

515

.

A A 00 .53523 A A rt A T r

. 000035 . 00010

p T a 518

.

00 .58503 A A A r\ A '"t .000042 .00010

C A T 521

.

00 .57933 . 000049 . 00010

524

.

00 .43678 A A /\ A d >4 .000044 .00010

527

.

00 .39690 . 000057 . 00010

530

.

00 .36174 . 000012 .00010

533

.

00 .38958 . 000046 . 00010

536

.

00 .54457 /v /"v r\ r- .000052 .00010

539

.

00 .69863 . 000066 .00010

542

.

00 .79247 .000062 .00010

545

.

00 .84006 . 000043 . 00010

548

.

00 .86137 . 000073 . 00010

551. 00 . 86587 . 000068 . 00010

554

.

00 .86482 .000057 . 00010

557

.

00 . 85997 . 000035 . 00010

560. 00 .84237 . 000045 .00010

563

.

00 .79728 . 000048 . 00010

566

.

00 .66681 . 000052 . 00010

569

.

00 .25719 . 000033 . 00010

572

.

00 . 02604 . 000010 . 00010

575. 00 . 03443 . 000011 . 00010

578. 00 . 05117 . 000012 . 00010

581. 00 . 06863 . 000007 . 00010

584. 00 .01549 .000007 . 00010

587. 00 .01577 . 000016 . 00010

590. 00 .04702 . 000023 . 00010

593. 00 .07588 . 000013 . 00010

596. 00 .19036 . 000034 .00010

599. 00 .32378 . 000038 . 00010

602. 00 .44667 .000041 . 00010

605. 00 . 56569 . 000048 . 00010

608. 00 .62507 .000047 . 00010

611. 00 .68076 .000072 . 00010

614. 00 .79774 . 000073 .00010

617. 00 . 87427 . 000086 .00010

SRM 2009

Wave AT A mAT

Length Standard System

(nm) T Error atic

501

.

50 .77050 .000062 . 00010

504

.

50 .73899 a a a a a r .000046 A A A 1 A

. 00010

507

.

50 /" A /" A A .69622 A A A A C A .000054 A A A 1 A

. 00010

510

.

50 .58889 A A A A A A .000023 A A A T A

. 00010

513

.

50 .51737 A A A A C A .000050 A A A 1 A

. 00010

516

.

50 .56547 A A A A A A .000033 AAA! A .00010

519

.

50 .59603 A A A A O .000038 A A A 1 A

. 00010

522

.

50 j— T A /" A .51464 A A A A C A .000058 A A A 1 A .00010

525

.

50 a a r a a .40684 A A A A A A .000029 A A A 1 A .00010

528

.

50 .367 34 A A A A T A .000019 A A A ~l A .00010

531

.

50 .37185 A A A A A /"" .000046 A A A 1 A .00010

534

.

50 A C A "7 a. 45072 A A A A A *7 .000037 A A A 1 A

. 00010

537 . 50 f~ A A O A .63283 A A A A A O .000038 A A A T A

. 00010

540

.

50 . 75111 A A A A A A. 000028 A A A T A .00010

543 . 50 .82093 A A A A C A .000050 A A A 1 A .00010

546

.

50 .85304 A A A A A .000068 A A A 1 A .00010

549. 50 .86532 . 000043 .00010

552

.

50 .86526 . 000035 .00010

555. 50 .86353 . 000038 .00010

558 . 50 .85316 .000088 . 00010

561. 50 .82504 . 000060 .00010

564. 50 .75134 . 000031 . 00010

567 . 50 . 50244 . 000030 . 00010

570. 50 . 07751 . 000011 . 00010

573. 50 . 02536 .000013 . 00010

576. 50 . 03857 . 000013 . 00010

579. 50 .06944 . 000014 .00010

582. 50 . 03836 . 000014 . 00010

585. 50 . 01027 . 000006 .00010

588. 50 . 02979 . 000022 .00010

591. 50 . 05748 . 000009 . 00010

594. 50 .11929 . 000028 . 00010

597. 50 .26661 . 000020 .00010

600. 50 .38146 . 000043 .00010

603. 50 .51047 . 000043 . 00010

606. 50 .60327 . 000074 .00010

609. 50 .64527 .000041 .00010

612. 50 .73522 . 000054 .00010

615. 50 . 84664 . 000067 .00010

618. 50 .88467 .000056 .00010

121
TABLE 4 (cont)

Wave AT AT

Length R t* r\ Pi yc\ i i y »J «— iii

( nm ) T Error a tic

620

.

00 .88413 000042 .00010

623 . 00 .87047 000037 .00010 • V/ w w -L_ V/ 626

.

00 .87359 .• 000066 \S \J \J Vy \J V .00010

629

.

00 .87008 .000069 . 00010

632

.

00 .87569 . 000048 .00010

635

.

00 .88828 . 000124 . 00010

638

.

00 .89322 . 000035 . 00010

641. 00 . 89755 . 000085 . 00010

644 . 00 .90014 . 000052 . 00010

647 . 00 . 90124 . 000041 . 00010

650. 00 .90106 . 000034 . 00010

653

.

00 . 90218 . 000054 . 00010

656

.

00 . 90301 . 000082 . 00010

659

.

00 . 90198 .000049 . 00010

662

.

00 .89951 . 000104 . 00010

665

.

00 . 89155 . 000045 . 00010

668

.

00 .87844 . 000079 .00010

671

.

00 .86691 .000077 . 00010

674 . 00 • 85883 U J U U J 000035 . 00010

677 . 00 .84419 000077 00010

680

.

00 .81611 000076 .00010

683 . 00 .77773 • 000111 V Will 00010

686 . 00 .77287 • 000111 u u u l l J. .00010

689

.

00 .80954 000080 00010

\J ZJ • on • 84399 (J *t J J J • 000066 U v U V U U 00010

695. 00 a R7O / J1 38> (J • oooosr V v U U J u 00010

698. 00 100/04 8 ft 7 4 0000^4 nnnin

701. 00 . 89577 . 000056 .00010

704. 00 . 89957 . 000049 . 00010

707. 00 . 90166 . 000056 .00010

710. 00 . 90225 . 000066 .00010

713. 00 .90041 .000056 .00010

716. 00 . 89593 .000042 .00010

719. 00 . 88755 .000075 . 00010

722. 00 . 87336 . 000061 . 00010

725. 00 .84758 .000054 .00010

728. 00 .79437 .000071 .00010

731. 00 . 66643 . 000039 . 00010

734. 00 . 40413 . 000053 .00010

737 . 00 .17772 . 000064 . 00010

SRM 2009

Wave LiATJ. AT

Length o Laiiuu L u O L Clll

( nm ) I mu / T Ci I—

L

621 . 50 . 87711 000071 • 00010 vUU 1U

624 . 50 .87083 000060 00010

627 . 50 .87310 . 000069 00010

630

.

50 . 87085 . 000064 • 00010 v_/ vy \y j_ \y 633 . 50 . 88221 .000043 .00010

636

.

50 .89117 .000089 .• 00010 V-* \j w -i— V 639

.

50 .89543 .000062 .00010 • w Vy Vy -L- *mS 642 . 50 . 89905 . 000051 00010

645 . 50 .90080 . 000043 .V 00010 w w w -i— w 648 . 50 .90112 . 000060 . 00010

651

.

50 .90149 .000079 . 00010

654 . 50 . 90300 .000066 .00010 • \J vy v_y -X- vy 657 . 50 . 90256 .000044 . 00010

660 . 50 . 90115 .000091 • V/ V/ V/ \y -I- . 00010

663 . 50 .89656 .000071 .00010

666 . 50 .88540 000079 .00010 • w \y \j i vy 669

.

50 .87177 000085 00010

67 2. 50 .86284 000056 00010

675

.

50 .85369 000076 00010

678 . 50 .83115 oooos 3 00010

681

.

50 .79779 • 000063 U U U u U J 00010

684 . 50 .76323 oooosi 00010

687 . 50 .79255 • \J \J \J \J ~J l 0001 0

690

.

50 .82685 * 00004 U U U U T JS • 00010 \J \J \J X \J 69\J Zt *J3 * 50 .85936 oooor? 0001 0

696. 50 88070 • U U \J \J O D 0001 0

699. 50 89254

702. 50 .89798 . 000040 . 00010

705. 50 . 90039 . 000060 .00010

708. 50 .90231 . 000071 . 00010

711. 50 . 90168 .000071 .00010

714. 50 .89850 . 000060 .00010

717. 50 .89232 . 000040 .00010

720. 50 .88137 .000049 . 00010

723. 50 .86256 . 000086 . 00010

726. 50 . 82620 . 000070 .00010

729. 50 .74399 .000039 .00010

732. 50 .55165 .000033 .00010

735. 50 .26498 . 000040 . 00010

738. 50 .14784 .000028 .00010

122
Wave AT

Length Standard

(nm) T Error

740

.

00 .14400 . 000017

743. 00 .16928 .000022

746. 00 . 19302 . 000027

749. 00 .17678 .000040

752. 00 .24335 .000050

755. 00 .34682 .000095

758. 00 .47017 .000099

761. 00 . 57256 .000071

764. 00 .64917 .000089

767. 00 .71596 . 000088

770. 00 .76342 .000040

773. 00 .78603 .000082

776. 00 .78665 .000098

779. 00 .75800 . 000083

SRM 2009

TABLE 4 (cont

)

AT WaveSystem- Length

atic (nm)

. 00010 741. 50

.00010 744.50

.00010 747.50

.00010 750. 50

.00010 753.50

.00010 756.50

.00010 759.50

.00010 762.50

.00010 765. 50

.00010 768.50

.00010 771.50

.00010 774.50

.00010 777.50

.00010 780.50

AT AT

Standard System

T Error atic

. 14841 . 000015 .00010

.19331 . 000020 . 00010

.17683 . 000014 .00010

.20220 . 000026 .00010

.29149 . 000049 .00010

.40869 . 000063 . 00010

.52523 .000164 . 00010

.61237 .000077 .00010

.68412 . 000093 .00010

.74294 . 000080 .00010

.77754 . 000144 .00010

.78934 . 000082 .00010

.77668 . 000050 .00010

.73040 . 000120 .00010

123
U.S. Department of Commerce

Juanita M. Kreps

Secretaryr"

National purrav of Standards

Ernest Aml>lrr pirector

^National bureau of jstfantlante

Certificate

Standard Reference Material 2010

Didymium Glass Filter for Checking the

Wavelength Scale of Spectrophotometers

Kenneth L. Eckerle and William H. Venable, Jr.

Serial Number:

This SRM is intended for use in calibrating the wavelength scale in the visible wavelength region of scanning

spectrophotometers having nominal bandwidths in the range 1.5 to 10.5 nm. Depending upon the bandwidth of

the spectrophotometer, anywhere from 14 to 24 wavelength corrections can be determined from 400 to 760 nm.

Detailed instructions on the use of this SRM and examples of its use are given in NBS Special Publication

260-66. Each didymium-glass filter is identified by the SRM number and a serial number.

The wavelengths of the transmittance minima as obtained from measurements on two filters representative of

the melt are given in Table 1 . These values are given for seven equally spaced values of the half-height width of

triangular passbands. The minima number is identified in the figure that illustrates the spectral transmittance as a function of wavelength. The wavelength values of nine points of inflection on the spectral transmittance curve

as obtained on two filters are given in Table 2. These inflection points are representative of the melt and are also

identified in the figure. These inflection points should only be used with the transmittance minima as described

in Sections 2.2 and 2.3 in SP 260-66.

The measurements on which these tables are based were made at 25 °C with a high-precision reference spectrophotometer that has a wavelength accuracy of 0.04 nm. Table 3 indicates the estimated random (as obtained

from 4 sets of measurements on a single filter) and systematic errors of the transmittance minima given in Table

1 . Table 2 also indicates the range of the measured wavelengths of the inflection points. Trial calibrations made

on several instruments, using both minima and inflection points, indicate that wavelength corrections made with

these SRM's can be accurate to 0.2 nm. The uncertainty of a calibration, however, will depend upon the stability

and other characteristics of a particular instrument.

The technical and support aspects involved in the preparation, certification, and issuance of this SRM were

coordinated through the Office of Standard Reference Materials by R. K. Kirby.

The spectral transmittance as a function of wavelength for a filter representative of the melt is given in Table 4. These values are not certified but are provided for use as specified in SP 260-66. They shouldnot be used to check

the photometric scale of a spectrophotometer.

It is recommended that the filter be handled only by its edges and when not in use it should be stored in the box

provided. If cleaning is necessary, wet the filter with water and rub gently with optical lens tissue soaked with a

mild soap solution, rinse with distilled water, rinse with isoprophyl alcohol, and rinse again with distilled water. Dry after each rinsing by wiping lightly with optical lens tissue.

Washington, D.C. 20234 George A. Uriano, Chief

January 8, 1980 (over) Office of Standard Reference Materials

124
Spectral transmittance of a typical didymium glass filter. Numbers

indicate the principal points of minimum transmittance and letters

indicate the principal points of inflection.

SRM 2010 125
Table I

Certified Wavelengths (nm) of the Transmit*." nee Minima for the Indicated Bandwidths

Mini

IUWIUU) mum No.

1 . 5 nm 1 A nmilm 4.5 nm 6.0 nm 7.5 nm y.Kj iiiii 10 S nm

1 402.42 401.81 401.69 401.66 401.42 400.95

2 431.50 432.48

3 440.27 440.52 441.84 442.52 442.37 442.08 441.33

4 445.59 445.14

5 472.72 472.58 472.88

6 478.89 479.34 479.28 478.31 477.36 476.50 475.65

7 513.45 513.61 513.89 514.31 515.38

g 529.58 530.02 529.90 529.47 529.27 529.12 528.88

9 572.69 573.27 574.21 575.11 576.59

10 585.34 585.54 585.77 586.02 585.99 585.35 584.42

11 623.62 624.02

12 629.53 629.41 628.56 627.03 627.02

13 684.66 684.68 684.71 684.72 684.71 684.66 684.58

14 739.86 739.96 740.24 740.91 742.01 742.97 743.65

15 748.28 748.10

Table 2

Wavelengths and Transmittances at Nine Selected

Points of Inflection

Point Wavelength Range* Transmittance t

Identification (nm) (nm)

A 406.44 +.08 0.7760

-.06

B 429.43 +.05 .7359

-.05

C 449.49 +.06 .6516

-.06

D 484.84 +.10 .6758

-.15

E 536.50 +.06 .5805

-.09

F 568.15 +.08 .4023

-.04

G 599.05 +.05 .3348

-.07

H 733.39 +.06 .4719

-.03

I 756.45 +.01 .4177

-.02

•The range of wavelengths within which the wavelength for the given trans- mittance will fall for symmetric triangular passbands with half-height bandwidths from 1.5 to 10.5 nm.

^ These values of transmittance are not certified. SRM 2010

126
Table 3

Estimated Random and Systematic Errors of the Transmittance Minima

Band Nominal Standard Deviation for Indicated Bandwidth Number Wavelength

of Minimum 1.5 nm 3.0 nm 4.5 run 6.0 nm 7.5 nm 9.0 nm 10.5 nm

Transmittance

1 402 nm

(O ff?)/"

11 0 018 nm 0.020 nm 0.021 nm 0.025 nm 0.029 nm

2 431 °TM 0.0.0 -

3 440

(0 05) 00,3 0 050 0 028 0 009 0 005 (OS)

7 ""1

4 446 °TM 0.029 _____ 5 473 0.0.2 0.032 -

6 479 0.013 0.009 0.009 0.009 0.014

0 022

7 573 0.016 0.014 0.013 0.010

8 530

(°°[ 2

0.010 0.010 0.011 0.010 0.011

0 004

9 573 0.010 0.010 0.012 0.014

10 585 ,TM!? 0.004 0.007 0.008 0.008 0.007

1. 624 £TM 0.061 _____ 12 630 j^0

0 12(> 0.171 0.133 0.091

13 685 0.029 0.024 0.017 0.014 0.014

(°*j2

14 740 0.013 0.011 0.010 0.009 0.009

t Values in parentheses are estimates of the systematic

0016

error. The estimates----- for the 1.5 nm bandwidth were obtained from the data taken at

1.5 nm intervals as compared to data taken at 0. .5 nm intervals. The method of estimating the systematic errors for the 10.5 nm bandwidth

is described in Section 3.4 in SP 260-66.

SRM 2010

127
TABLE 4

Transmittance (T) as a function

for a bandwidth of 1.5 nm. The

errors are also provided.

Wave AT AT

Length Standard System

(nm) T Error atic

380. 00 .61832 .000054 .00010

383. 00 .66210 .000064 .00010

386. 00 .70112 .000047 . 00010

389. 00 .73590 .000095 .00010

392. 00 .76201 .000083 .00010

395. 00 .77620 . 000064 .00010

398. 00 .75013 .000069 .00010

401. 00 .70966 . 000070 .00010

404. 00 .73683 .000057 .00010

407. 00 .77756 .000088 .00010

410. 00 .82277 .000058 .00010

413. 00 .83115 .000060 .00010

416. 00 .83222 .000060 .00010

419. 00 .83277 . 000059 .00010

422. 00 .83711 .000064 .00010

425. 00 .83511 .000049 .00010

428. 00 . 81620 . 000055 .00010

431. 00 .62212 .000096 .00010

434. 00 .64183 .000057 .00010

437. 00 .61858 .000049 .00010

440. 00 .59163 .000064 .00010

443. 00 .60082 .000063 .00010

446. 00 .59315 -.000055 .00010

449. 00 .63551 .000083 .00010

452. 00 .68002 .000069 .00010

455. 00 .70206 . 000027 .00010

458. 00 .69051 .000025 .00010

461. 00 .64890 .000057 .00010

464. 00 .63837 .000070 .00010

467. 00 .62094 .000072 .00010

470. 00 .59042 .000008 .00010

473. 00 . 56160 . 000033 .00010

476. 00 .59528 .000052 .00010

479. 00 .54953 .000070 .00010

482. 00 . 57326 . 000025 .00010

485. 00 .67764 . 000052 .00010

488. 00 . 75412 .000045 .00010

491. 00 . 80556 .000035 .00010

494. 00 . 82117 .000063 .00010

497. 00 .81233 .000096 .00010

SRM 2010

of wavelength from 380 to 780.5 nm

estimates of random and systematic

These data are not certified.

Wave AT AT

Length Standard System

(nm) T Error atic

381. 50 .63896 . 000085 . 00010

384. 50 .68291 . 000079 .00010

387. 50 .71885 .000071 .00010

390. 50 .74954 . 000040 .00010

393. 50 .77104 .000055 .00010

396. 50 .77123 . 000038 .00010

399. 50 .72419 . 000079 .00010

402. 50 .69505 . 000071 . 00010

405. 50 .75886 . 000047 .00010

408. 50 .80673 . 000072 .00010

411. 50 .82813 .000038 . 00010

414. 50 .83287 . 000075 . 00010

417. 50 .83200 . 000029 . 00010

420. 50 . 83844 . 000066 . 00010

423. 50 . 83328 . 000052 . 00010

426. 50 .83414 . 000045 .00010

429. 50 . 72877 . 000023 . 00010

432. 50 .63478 . 000039 .00010

435. 50 .63392 . 000059 . 00010

438. 50 .60090 . 000038 .00010

441. 50 .59496 . 000053 . 00010

444. 50 .59576 . 000068 . 00010

447. 50 .60769 . 000044 . 00010

450. 50 .66313 . 000060 .00010

453. 50 .69110 . 000057 . 00010

456. 50 .70341 . 000033 .00010

459. 50 .66807 . 000049 .00010

462. 50 .63966 . 000060 .00010

465. 50 .63353 .000040 . 00010

468. 50 .60572 .000053 .00010

471. 50 .57213 .000072 .00010

474. 50 .58414 .000031 .00010

477. 50 .56003 .000052 . 00010

480. 50 .55659 .000036 .00010

483. 50 .62009 .000040 . 00010

486. 50 .72126 . 000072 .00010

489. 50 .78321 . 000082 . 00010

492. 50 .81759 .000060 .00010

495. 50 .81916 .000038 .00010

498. 50 .80115 .000044 .00010

128
TABLE 4 (cont)

Wave — AT AT

Length Standard System

(nm) T Error atic

500. 00 .78689 .000060 .00010

503. 00 .75433 .000047 .00010

506. 00 .72185 .000070 .00010

509. 00 .65070 .000060 .00010

512. 00 .53799 .000044 .00010

515. 00 .53523 .000035 .00010

518. 00 .58503 .000042 .00010

521. 00 .57933 .000049 .00010

524. 00 .43678 .000044 .00010

527. 00 .39690 .000057 .00010

530. 00 .36174 .000012 .00010

533. 00 .38958 .000046 .00010

536. 00 .54457 .000052 .00010

539. 00 .69863 .000066 .00010

542. 00 .79247 .000062 .00010

545. 00 .84006 .000043 .00010

548. 00 .86137 .000073 .00010

551. 00 .86587 .000068 .00010

554. 00 .86482 .000057 .00010

557. 00 .85997 .000035 .00010

560. 00 .84237 .000045 .00010

563. 00 .79728 .000048 .00010

566. 00 .66681 .000052 .00010

569. 00 .25719 .000033 .00010

572. 00 .02604 .000010 .00010

575. 00 . 03443 -.000011 .00010

578. 00 .05117 .000012 .00010

581. 00 .06863 .000007 .00010

584. 00 .01549 .000007 .00010

587. 00 .01577 . 000016 .00010

590. 00 .04702 .000023 .00010

593. 00 .07588 .000013 .00010

596. 00 .19036 .000034 .00010

599. 00 .32378 .000038 .00010

602. 00 .44667 .000041 .00010

605. 00 .56569 .000048 .00010

608. 00 .62507 .000047 .00010

611. 00 .68076 .000072 .00010

614. 00 .79774 .000073 .00010

617. 00 .87427 .000086 .00010

SRM 2010

Wave AT AT

Length Standard System

(nm) T Error atic

501. 50 .77050 .000062 .00010

504. 50 .73899 .000046 .00010

507. 50 .69622 .000054 .00010

510. 50 .58889 .000023 .00010

513. 50 .51737 .000050 .00010

516. 50 .56547 .000033 .00010

519. 50 .59603 .000038 .00010

522. 50 .51464 .000058 .00010

525. 50 .40684 .000029 .00010

528. 50 .36734 .000019 .00010

531. 50 .37185 .000046 .00010

534. 50 .45072 .000037 .00010

537. 50 .63283 .000038 .00010

540. 50 .75111 .000028 .00010

543. 50 .82093 .000050 .00010

546. 50 .85304 .000068 .00010

549. 50 .86532 .000043 .00010

552. 50 .86526 .000035 .00010

555. 50 .86353 .000038 .00010

558. 50 .85316 .000088 .00010

561. 50 .82504 .000060 .00010

564. 50 .75134 .000031 .00010

567. 50 .50244 .000030 .00010

570. 50 .07751 .000011 .00010

573. 50 .02536 .000013 .00010

576. 50 .03857 .000013 .00010

579. 50 .06944 .000014 .00010

582. 50 .03836 .000014 .00010

585. 50 .01027 .000006 .00010

588. 50 .02979 .000022 . 00010

591. 50 .05748 .000009 .00010

594. 50 .11929 .000028 .00010

597. 50 .26661 .000020 .00010

600. 50 .38146 . 000043 .00010

603. 50 .51047 .000043 .00010

606. 50 .60327 .000074 . 00010

609. 50 .64527 .000041 .00010

612. 50 .73522 .000054 .00010

615. 50 .84664 .000067 .00010

618. 50 .88467 .000056 .00010

129
TABLE 4 (cont)

Wave AT AT

Length Standard Svsteni *—f J w *— V— ill

\

( 1nni) 1111 / T Error a tic

620

.

00 .88413 000042 . 00010

623

.

00 .87047 .000037 .00010

626

.

00 .87359 .000066 .00010

629

.

00 .87008 .000069 . 00010

632

.

00 .87569 .000048 .00010

635

.

00 .88828 • \J \J \J mm \J 000124 .00010

638

.

00 .89322 .000035 .00010

641

.

00 .89755 .000085 . 00010

644

.

00 .90014 .000052 . 00010

647

.

00 .90124 . 000041 .00010

650

.

00 .90106 000034 . 00010

653

.

00 .90218 .000054 .00010

656

.

00 .90301 000082 . 00010

659. 00 .90198 .000049 .# 00010 \J V-r w V 662

.

00 .89951 .000104 . 00010

665 • 00 .89155 .000045 . 00010

668

.

00 .87844 . 000079 .00010

671 V / X * 00\J \J .86691 000077 .00010

674 00\J \J .85883 • 000035 KJ KJ KJ \J ~J ~J 00010

677 00\J \J .84419 000077 00010

680 \J O v * 00kj \j .81611 • 000076 \J \J KJ KJ 1 \J 00010

D O J • .77773 000111 00010

U O \J • 00V \J • 000111 KJ KJ KJ X J—

L

00010

nn 80954 ooooao 00010

no\J \J • OQ 4*i J^qqj V 000066 00010

o y d o Of) KJ KJ R7 1 • O / 1 JO~\ R nnn or

r

• UUUU JO

698. 00 R R 7 d nnnn • v w U i U

701. 00 Rq S77 nnnnsfi nnm n 704. 00 .89957 .000049 .00010

707. 00 .90166 .000056 .00010

710. 00 .90225 .000066 .00010

713. 00 . 90041 .000056 .00010

716. 00 .89593 .000042 .00010

719. 00 . 88755 .000075 .00010

722. 00 .87336 .000061 .00010

725. 00 .84758 .000054 .00010

728. 00 .79437 . 000071 .00010

731. 00 .66643 .000039 .00010

734. 00 .40413 .000053 .00010

737. 00 .17772 .000064 .00010

SRI-I 2010

Wave AT LiATX Length JV O LCKl

( nirii T Prrnr UX J. WJ- a i

l 621

.

50 .87711 • 000071 \J KJ \J KJ 1 ±. • 0001 KJ \J KJ JL 0KJ 624

.

50 .87083 000060 • 00010 KJ KJ KJ X KJ 627

.

50 .87310 000069 • 00010 KJ KJ KJ X KJ 630

.

50 .87085 • 000064 \J \J KJ \J KJ ^ 00010 KJ \J KJ ± \J 633

.

50 . 88221 • 000043 KJ KJ \J KJ T _1 • 00010 KJ KJ KJ X KJ 636

.

50 . 89117 • 000089 KJ KJ KJ KJ KJ • 00010 KJ \J KJ X KJ 639

.

50 . 89543 • 000062 \J KJ KJ \J KJ £m • 00010 \J KJ KJ J^ KJ 642

.

50 .89905 • 000051 KJ KJ KJ KJ _t X • 00010 KJ KJ KJ X KJ 645

.

50 . 90080 000043 • 00010 KJ \J KJ ± KJ 648

.

50 . 90112 000060 • 00010 \J KJ KJ X KJ 651

.

50 .90149 • 000079 KJ KJ \J KJ 1 y • 00010 KJ KJ KJ ± KJ 654 . 50 .90300 • 000066 KJ KJ KJ KJ KJ KJ • 00010 \J KJ \J J^ KJ 657

.

50 . 90256 000044 • 00010 KJ KJ \J ± KJ 660

.

50 . 90115 • 000091 KJ KJ KJ ' J J J_ * 0001 \J KJ KJ X 0KJ 663

.

50 .89656 • 000071 <J KJ KJ KJ 1 X • 00010 KJ KJ KJ X \J 666

.

50 .88540 * 000079 \J KJ KJ KJ 1 J • 00010 KJ KJ KJ X KJ 669

.

50 .87177 000085 • 00010 'J KJ KJ X \J 672

.

50 .86284 • 000056 \^ W K-i KJ ~) KJ • 00010 \J KJ KJ X KJ 675 50 .85369 • 000076 KJ KJ \J KJ / \J * 0001 KJ KJ KJ J. 0KJ fi7fi 50 .83115 • JU JU J

J

. 0U U001U 1 0u 681 \J O X • 50 79779 • 00006 U J U U O J1 . 0u 0u 01u x 0u 684 50 76323 000051 • 0U 001 U U X 0u DO/. 50~) KJ 79255 0 0 0 0 5 7 o om n

O -/ \J . ~J5nKJ 82685 . 00004 U U U U *i J5 . 0001 UUU1U0

6Q

1

50 85936 00 0 0 5

5

. UUU1U

6Q6 ^n » RRn7 O O KJ 1 nKJ . UUUU JO . UUU1U

COO U77 t ^n 89254 . 0U 0U 0U 0U £,9 9J • U U U X u 702. 50 R9798 . UUUU4U . ooo u u u xi nu 705. 50 on n ^ q . U U U U 0 u . UUU1U

708. 50 .90231 .000071 . 00010

711. 50 . 90168 .000071 . 00010

714. 50 .89850 . 000060 . 00010

717. 50 .89232 .000040 . 00010

720. 50 .88137 .000049 . 00010

723. 50 .86256 .000086 .00010

726. 50 .82620 . 000070 . 00010

729. 50 .74399 .000039 . 00010

732. 50 .55165 .000033 . 00010

735. 50 .26498 .000040 .00010

738. 50 .14784 .000028 .00010

130
TABLE 4 (cont)

Wave mm AT AT

Length Standard Svstsm

(nm) T Error atic

740. 00 . 14400 . 000017 . 00010

743. 00 . 16928 . 000022 . 00010

746. 00 . 19302 . 000027 . 00010

749. 00 .17678 .000040 .00010

752. 00 .24335 .000050 .00010

755. 00 .34682 .000095 .00010

758. 00 .47017 .000099 .00010

761. 00 .57256 .000071 .00010

764. 00 .64917 .000089 .00010

767. 00 .71596 .000088 .00010

770. 00 .76342 .000040 .00010

773. 00 .78603 .000082 .00010

776. 00 .78665 .000098 .00010

779. 00 .75800 .000083 .00010

SRM 2010

Wave AT AT

Length Standard System

(nm) T Error atic

741. 50 .14841 .000015 . 00010

744. 50 .19331 . 000020 .00010

747. 50 .17683 . 000014 . 00010

750. 50 .20220 .000026 .00010

753. 50 .29149 .000049 .00010

756. 50 .40869 .000063 .00010

759. 50 .52523 .000164 .00010

762. 50 .61237 .000077 .00010

765. 50 .68412 .000093 .00010

768. 50 .74294 .000080 . 00010

771.50 .77754 .000144 .00010

774. 50 .78934 . 000082 .00010

777. 50 .77668 .000050 .00010

780. 50 .73040 .000120 .00010

131
U.S. Department of Commerce

JuanitH M Krt-ps ctrctarv v:. r J

National Bumui of Sllimliinln Ernent Ambler, Dirwtor

Rational ^Bureau of j^tartdartte

(Eerttfttats

Standard Reference Material 2013

Didymium Glass Filter for Checking the

Wavelength Scale of Spectrophotometers

Kenneth L. Eckerle and William H. Venable, Jr.

Serial Number:

This SRM is intended for use in calibrating the wavelength scale in the visible wavelength region of scanning

spectrophotometers having nominal bandwidths in the range 1 .5 to 10.5 nm. Depending upon the bandwidth of

the spectrophotometer, anywhere from 14 to 24 wavelength corrections can be determined from 400 to 760 nm.

Detailed instructions on the use of this SRM and examples of its use are given in N'BS Special Publication

260-66. Each didymium-glass filter is identified by the SRM number and a serial number.

The wavelengths of the transmittance minima as obtained from measurements on each filter are given in Table I. These values are given for seven equally spaced values of the half-height width of triangular passbands. The

minima number is identified in the figure that illustrates the spectral transmittance as a function of wavelength.

The wavelength values of nine points of inflection on the spectral transmittance curve as obtained on three filters are given in Table 2. These inflection points are representative of the rnelt and are also identified in the figure.

These inflection points should only be used with the transmittance minima as described in Sections 2.2 and 2.3 in SP 260-66.

The measurements on which these tables are based were made at 25 °C with a high-precision reference spectrophotometer that has a wavelength accuracy of 0.04 nm. Table 3 indicates the estimated random (as obtained

from 4 sets of measurements on a single filter) and systematic errors of the transmittance minima given in Table

1. Table 2 also indicates the range of the measured wavelengths of the inflection points. Trial calibrations made

on several instruments, using both minima and inflection points, indicate that wavelength corrections made w ith these SRM's can be accurate to 0.2 nm. The uncertainty of a calibration, however, will depend upon the stability

and other characteristics of a particular instrument.

The technical and support aspects involved in the preparation, certification, and issuance of this SRM were

coordinated through the Office of Standard Reference Materials by R. K. Kirby.

The spectral transmittance as a function of wavelength for this filter is given in Table 4. These values are not

certified but are provided for use as specified in SP 260-66. They should not be used 10 check the photometric

scale of a spectrophotometer.

It is recommended that the filter be handled only by its edges and w hen not in use it should be stored in the box

provided. 11 cleaning is necessary, wet the filter with water and rub gently with optical lens tissue soaked with a mild soap solution, rinse with distilled water, rinse with isopropvl alcohol, and rinse again w ith distilled water. Dry after each rinsing by wiping lightly with optical lens tissue.

Washington. D.C. 20234 George A. Uriano, Chief

Januarys, 1980 (over) Office of Standard Reference Materials

132
Spectral transmi ttance of a typical didymium glass filter. Numbers

indicate the principal points of minimum transmi ttance and letters

indicate the principal points of inflection.

SRM 2013 1 33
TABLE 1

SRM 2013

FILTFR Fl

Wavelengths (nm) of the transmittance minima

for the indicated bandwidths.

-WIDTH 1 . 5NM 3..0NM 4.5flM 6.0 MM 7.5NM 9.0NM 10.5NM

tfUM NO,

i

l\ \_ X • 0 U 400 » £4

d 4 3 .1 • j1 432 • 46

-2o 44'.> • 2u 441 .41 441 . 62 442 .43 <+42 • 26 441 .92 44] ,06

4 1 45 . 17

b

V 47^ » 73 47? . 60 472 . 97

6 478,31 479. 28 479. ?2 478 , ?8 477.37 476. i>4 475 * 68

7 513.43 513.61 513.89 514.31 515.38

8 529.65 530.11 53t .00 529.54 529.32 529.17 528.92

9 57?.68 573.25 574.17 575,06 •^76.51

10 585.35 585.^4 585.76 586.02 585.99 585.36 584.44

11 6?3.58 623.96

12 629.39 629.28 628.39 627.04 626.98

13 634.62 684.67 664.72 684.74 684.72 684.68 684.59

739.87 739.95 74t>.25 740.91 742.00 742.95 743.63

15 7<i8.25 748.09

134
Table 2

Wavelengths and Transmittances at Nine Selected

Points of Inflection

Point Wavelength Range* Transmiltance^

Identification (nm) (nm)

A 406.38 +.08 0.7562

-.06

B 429.42 +.05 .7293

-.05

C 449.45 +.06 .6514

-.06

D 484.77 +.10 .6743

-.15

E 536.52 +.06 .5801 -.09

F 568.16 +.08 .4008

-04

G 598.99 +.05 .3346

-.07

H 733.45 +.06 .4730

-.03

I 756.48 +.01 .4215

-.02

•The range of wavelengths within which the wavelength for the given trans- mittance will fall for symmetric triangular passbands with half-height bandwidths from 1.5 to 10.5 nm.

^These values of transmittance are not certified.

SRM 2013

135
Table 3

Estimated Random and Systematic Errors of the Transmittance Minima

Band Nominal Standard Deviation for Indicated Bandwidth

Number Wavelength

of Minimum 1.5 nm 3.0 run 4.5 nm 6.0 nm 7.5 nm 9.0 nm 10.5 run Transmittance

1 402 nm (0 07)!""

1 0.018 nm 0.020 nm 0.021 nm 0.025 nm 0.029 nm

0010 ----- 3 440

(JTM 0.013 0.050 0.028 0.009 0.005

( J~

7 nm

4 446

0 023 4 446

(0.06) 0 029 _____ 5 473 TM] 0.0.2 0.032 -

6 479 (0 ^5) 0013 0 009 0 009 0 009 0 0M

(0 25)

7 ^573 "J?22

0.016 0.014 0.013 0.010

0012 0010

8 530 (021>

0010 0010 00 " 0010

(0 25)

9 573

(0 05) 0010 0 010 0 012 0 014

0 007 0.007 10 585 "l" 0.004 0.007 0.008 0.008 0.007

(0.06) i.u._3i ss ..«.----

12 630 ,^2) 0.120 0.171 0.133 0.091

0 019 0.012

13 685 0.029 0.024 0.017 0.014 0.014

(0 25)

oooq 0010

14 740 0.013 0.011 0.010 0.009 0.009

(() ,5) '*•»

TValues in parentheses are estimates of the systematic

U.

error. The estimates----- for the 1.5 nm bandwidth were obtained from the data taken at

1.5 nm intervals as compared to data taken at 0.15 nm intervals. The method ot estimating the systematic errors lor the 10.5 nm bandwidth

is described in Section ?,4 in SP 2b0-t>6.

SRM 2013

136
TABLE 4

Transmittance (T) as a function

for a bandwidth of 1.5 nm. The

errors are also provided.

of wavelength from 380 to 780.5 nm

estimates of random and systematic

These data are not certified.

SRM 2013 >

FILTER FT

WAVE- AT AT

LENGTH STANDARD SYSTEM-

(NM) T ERROR ATIC

380.00 .56826 .000170 .00020

383.00 .61819 .000414 .00020

386.00 .66334 .000164 .00020

389.00 .70209 .000180 .00020

392.00 .73218 .000311 .00020

395.00 .75013 .000192 .00020

398.00 .73081 .000117 .00020

401.00 .69713 .000221 .00020

404.00 .72530 .000145 .00020

407.00 .76637 .000251 .00020

410.00 .80982 .000363 .00020

413.00 .81971 .000283 .00020

416.00 .82240 .000759 .00020

419.00 .82486 .000104 .00020

422.00 .83008 .000438 .00020

425.00 .82968 .000319 .00020

428.00 .81277 .000419 .00020

431.00 .63172 .000282 .00020

434.00 .65066 .000080 .00020

437.00 .63043 ,000157 .00020

440.00 .60685 .000107 .00020

443.00 .61614 .000432 .00020

446.00 .60856 .000158 .00020

449.00 .64896 .000076 .00020

452.00 .69049 .000149 .00020

455.00 .71162 .000204 .00020

458.00 .70059 .000321 .00020

461.00 .66115 .000298 .00020

464.00 .65116 .000283 .00020

467.00 .63481 .000079 .00020

470.00 .60647 .000136 .00020

473.00 .57923 .000046 .0002"

476.00 .61005 .000147 .00020

479.00 .56568 .000153 .00020

482.00 .59022 .000046 .00020

485.00 .68932 .000182 .00020

488.00 .76066 .000155 .00020

491.00 .80852 .000562 .00020

494.00 .82309 .000165 .00020

497.00 .81518 .000217 .00020

WAVE- AT AT

LENGTH STANDARD SYSTEM-

(NM) T ERROR ATIC

381.50 .59269 .000157 .00020

384.50 .64237 .000146 .00020

387.50 .68330 .000040 .00020

390.50 .71751 .000170 .00020

393.50 .742Q7 .000285 .00020

396.50 .74790 .000287 .00020

399.50 .70*79 .000257 .00020

402.50 .68509 .000284 .00020

405.50 .747^6 .000149 .00020

408. SO .79408 .000298 .00020

411.50 .815*1 .000324 .00020

414.50 .82266 .000274 .00020

417.50 .82338 .000166 .00020

420.50 .83065 .000296 .00020

423.50 .82672 .000155 .00020

426.50 .82907 .000235 .00020

429.50 .73163 .000432 .00020

432.50 .642*8 .000177 .00020

435.50 .64411 .000700 .00020

438.50 .61489 .000182 .00020

441.50 .61053 .000129 .00020

U44.50 .61099 .000079 .00020

447. SO .62206 .000281 .00020

450.50 .67502 .000303 .00020

453.50 .70122 .000186 .00020

456.50 .71301 .000432 .00020

459.50 .67909 .000086 .00020

462.^0 .65213 .000162 .00020

465.50 .64672 .000567 .00020

468.50 .62065 .000153 .00020

471.50 .5891.000250 .00020

474.50 .59P73 .000142 .00020

477,50 .57523 .000162 .00020

480.50 .57355 .000152 .00020

483.50 •634P3 .000428 .00020

486.50 .72979 .000150 .00020

489. SO .78717 .000195 .00020

492.50 .819R5 .000123 .00020

495.50 .82132 .000217 .00020

498.50 .80472 .000287 .00020

137
TABLE 4 (cont)

5PM 2013

FILTER Fl

nftvt ft 1 A T A 1 Ul A W C mm A T A. 1 A

A T1 LLIw 1 ti CTftMnAon b 1 WIMI.JAKU 1UtNv? rMCTUI n b 1 AND AKI) bib I t"""

i MM 1

1 CDD AD A T 1 U

/ MM \ ERROR ATT/* A T IC

txft n nn 7q ft 1 O nnnndn . UlHIUtU ft ft ft ft ft • U U 0 c. 0 5U 1 • 50 77/ < 7 . 1 roll A A A 1 1 1 O

• ooum 6

ft ft ft ft ft . 00U20

jUj • UU . (Dint lUUUl n n fi 1 771 f

ft ft ft O ft CAfl C A 5UM- • 5U 7/1 700 n a n fi fi q • U 0 U M- H0ft ft n ft ft . U U U td u ca/ ft a bub. 00 • f olr> 7

ft ft n ft O n . 0002?0 ft CI f\ ft ft . 00020 50 f • 50 7n77n • 707^2 ft ft A 4 C A

. 000150 ft ft ft ft ft . 00020

rrtQ Aft

. oo'+bM- ft ft ft ft C Tl • OOOOoo A A A• 00020 C 1 A IT A 510 • 50 A C A f» • 605?8 ft r\ ft "1 7ft

. 000132 ft ft ft ft ft . 00020

512.00 e? et ft, 4 • 55721 ft. ft. ft 4 r ft. • 0001.58 ft. ft ft A ft • 00020 t— 4 f— ft 513.50 . 5371

1

ft ft ft ft 4 /~\ • 000219 ft ft ft ft ft .00020

515.00 • 55442 ft ft. ft n .000278 ft ft ft ft ft . 00020 r~ 4 /*" it ft 516.50 . 58295 ft ft ft ft r- .000295 ft a ft ft ft • 00020

518.00 .60182 .000176 .00020 519.50 .61259 .000049 ft ft ft ft ft .00020

521 .00 .59589 .000325 .00020 522.50 • 53474 .000066 .00020

524.00 .45922 .000156 . 00020 525.50 .43025 .000068 .00020

527. 00 .42096 . 000052 .00020 528.50 . 391 12 . 000298 ft ft ft ft ft .00020

530 .00 • 38444 A> j-, ft ft f"\ 4 .000291 ft ft ft ft ft .00020 r~ — 4 rr ft 531 .50 • 39373 .000133 ft ft ft ft ft .00020

533.00 . 40937 .000046 .00020 534.50 .46919 .000285 .00020

536.00 . 56132 .000291 . 00020 537.50 .64638 .000261 .00020

539.00 .70929 .000179 .00020 540 . 50 .75823 .000230 .00020

512.00 .79724 .000249 .00020 543.50 . 82355 .000459 ft ft fti ft • 00020

515. 00 .84153 .000133 . 00020 546.50 • 85337 .000569 .00020

54-8.00 . 86176 ft ft ft^ i

.

.000433 . 00020 549. 50 • 86^80 .000114 ft ft ft ft ft .00020

551.00 .86603 .000197 • 00020 552.50 • 86524 .000154 ft ft ft ft .00020

554. 00 .86411 .000248 .00020 555. 50 . 863Q 3

ft ft ft ft fa .000204 ft ft A ft ft . 00020

557.00 . 86019 .000330 . 00020 558.50 . 85370 ft A ft f A A f .000415 ft ft ft ft ft .00020

560.00 . 84381 . 000175 .00020 561.50 . 82721 .000163 . 00020

563. 00 .80172 .000166 ft ft ft ft ft .00020 564 • 50 et ~9 ft, r\ . 75799 ft. ft ft 4 jft .000319 ft ft ft ft ft • 00020

566. 00 /• ^ ft 4 • 67701 .000567 ft ft ft fti ft .00020 567 . 50 ET 4 f\ f? ft} • 51959 ft ft ft ft I. A• 000042 ft ft ft ft ft • 00020

569. 00 ft. TMt r- p. i— . 27505 . 000025 .00020 570 • 50 .088^2 . 000015 ft ft ft ft ft . 00020

572.00 .03214 . 000140 • 00020 573.50 .03157 .000004 ft ft ft *K ft .00020

575.00 . 04230 .000007 .00020 576 . 50 . 04757 ft ft Aft 4 J ft .000140 ft ft A ft ft • 00020

578.00 . 0621

8

ft ft. ft ft ft. .000009 ft ft ft ft ft .00020 579. 50 .082^3 ft ft ft 4 f 1 ft .000140 ft ft ft ft ft • 00020

581.00 .08243 .000013 .00020 582.50 .04771 .000014 .00020

584.00 .02048 .000140 .00020 585.50 .01397 .000140 .00020

587.00 .02077 .000133 .00020 588.50 .03775 .000140 .00020

590.00 .05781 .000281 .00020 591.50 .06923 .000148 .00020

593.00 .08936 .000140 .00020 594.50 .13635 .000025 .00020

596.00 .21181 .000135 .00020 597.50 .29016 .000281 .00020

599.0 0 .34754 .000141 .00020 600.50 .40480 .000428 .00020

602.00 .46864 .000091 .00020 603.50 .53042 .000211 .00020

605.00 .58254 .000306 .00020 606.50 .61750 .000446 .00020

608.00 .63714 .010224 .00020 609.50 .65620 .000179 .00020

611.00 .68948 .000223 .00020 612.50 .74227 .000301 .00020

614.00 .80146 .000361 .00020 615.50 .84857 .000309 .00020

617.00 .87426 .000174 .00020 618.50 .88386 .000280 .00020

138
TABLE 4 (cont)

SRM 2013

FILTFR Fl

WAVE- AT AT WAVE- AT AT

LENGTH STANDARD SYSTEM- LENGTH STANDARD SYSTEM-

( NM) T ERROR ATIC (N M ) T ERROR • T Y ft ATIC

620*00 • 88356 ft ft i 4 .000451 .00020 621 .50 .87770 .000300 .00020

623*00 • 87126 ft n ft ^ ft) c• 000325 .00020 624.50 ,87137 ft A ft ft /V ft .000288 ft ft ft ft ft .00020

bdo* 00 . o f*b f 0 ft n i rs c ft ft ft ft ft • 00020 ^ ft "7 tz ft 62 f • SO , o f 3^3 ft ft ft 4 7C * 000 1 7r> n n n ^ n • U U U 2 U

r ft rt ft ft 629.00 • 8713b n ft ft #i ^ ft • 000160 ft ft ft ft ft . 00020 ft c? ft 630 .50 • 87220 ft ft ft 4 ft • O00318 a n a n

• 00020

632 • 00 • 87635 ft ft ft T 4 f i . 000311 ft ft ft ft ft • 00020 633 .50 , 88260 ft ft ft ft ft fl • 000484 • 00020

r V C ft ft 635*00 ft ft ft ** • 88866 ft ft ft li It ft • 000^42 ft ft ft ft ft • 00020 636.50 ft f\ ft ft ft ft ft ! ft 4 • 000321 ft ft ft ft ft 00020

638.00 . 89261 • 000454 .00020 639.50 . 89402 .000429 ft ft ft ft ft .00020

6m. 00 .89653 .000436 .00020 642.50 . 89780 .000162 ft ft ft ft ft .00020

644.00 .89874 .000301 .00020 645.50 . 89908 .000288 ft ^\ ft a .00020

647.00 .89973 .000443 .00020 648.50 . 899Q7 .000153 ft ft ft ft ft • 00020

650.00 .89978 .000599 .00020 651.50 .89990 .000169 .00020

653.00 .90073 .000444 .00020 654.50 .90233 .000301 .00020

656.00 .90125 .000286 .00020 657.50 .90092 .000151 • 00020

659.00 .90117 .000230 .00020 660.50 .90041 .000141 .00020

662.00 .89832 .000319 .00020 663.50 .89540 .000108 .00020

665.00 .89067 .000202 .00020 666.50 .8851

4

.00^196 .00020

668.00 .87868 . 000244 .00020 669.50 .872^7 .000146 .00020

671.00 .86809 .000126 .00020 672.50 . 86472 • 000277 . 00020

674.00 .86099 .000068 .00020 675.50 . 85638 .000177 .00020

677.00 .84756 .000040 .00020 678.50 • 835*5 . 000148 .00020

680.00 .82177 .000569 .00020 681 .50 * 80482 .000565 .00020

683.00 ,78521 .000433 . 00020 684.50 .77166 .000701 ft ft ft ft ft .00020

686.00 .78125 .000450 • 00020 687.50 , 79876 ft »-v ft (• fl .000447 ft ft ft ft ft .00020

689.00 .81476 .000446 .00020 690 . 50 . 83135 .000534 . 00020

692.00 .84711 .000311 . 00020 693.50 .86183 .000173 ^ ft ft ft . 00020

695.00 .87321 .000479 . 00020 696.50 . 88055 .000477 ft ft ft #"v ft • 00020

698.00 .88810 .000139 .00020 699.50 .89189 .000726 .00020

701 .00 . 89477 .000566 .00020 702 . 50 • 89720 ft ft ft ii ft .000450 ft ft ft ft ft • 00020

704.00 .89838 .000493 .00020 705.50 .899^7 .000201 .00020

707.00 .90040 .000699 .00020 708.50 .90159 .000420 .00020

710.00 .90163 .000718 .00020 711.50 .90017 .000256 .00020

713.00 .89930 .000531 .00020 714.50 .89791 .000350 .00020

716.00 . .89503 .000235 .00020 717.50 .89179 .000622 .00020

719.00 .88721 .000492 .00020 720.50 .88172 .000751 .00020

722.00 .87433 .000460 .00020 723.50 .86430 .000694 .00020

725.00 .85137 .000694 .00020 726.50 .83115 .000708 .00020

728.00 .80108 .000141 .00020 729.50 .75514 .000303 .00020

731.00 .68274 .000730 .00020 732.50 .574^0 .000303 .00020

734.00 .43291 .000088 .00020 735.50 .29391 .000010 .00020

737.00 .2013B .000071 .00020 738.50 .16904 .000011 .00020

139
TABLE 4 (cont)

SRM ?013

FILTER Fl

WAVE- AT AT WAVE- AT AT

LENGTH STANDARD SYSTEM- LENGTH STANDARD SYSTEM-

(NM) T ERROR ATIC (NM) T ERROR ATIC

740.00 . 16460 .000141 .00020 741 .50 . 16966 .000142 .00020

743.00 • 19210 • 000150 .00020 744 • 50 .21749 .000133 • 00020

746.00 .21796 .000292 .00020 747.50 .20096 .000137 .00020

749.00 .20125 .000424 .00020 750.50 .22781 .000040 .00020

752.00 .26948 .000566 .00020 753.50 .31813 .000429 .00020

755.00 .37350 .000060 .00020 756.50 .43373 .000428 .00020

758.00 .49359 .000309 .00020 759.50 .54744 .000327 .00020

761.00 .59259 .000129 .00020 762.50 .63007 .000265 .00020

764.00 .66575 .001325 .00020 765.50 .69808 .000720 .00020

767.00 .72868 .000358 .00020 768.50 .75426 .000255 .00020

770.00 .77239 .000468 .00020 771.50 .78515 .001001 .00020

773.00 .79374 .000564 .00020 774.50 .79578 .000900 .00020

776.00 .79383 .000269 .00020 777.50 .78466 .000367 .00020

779.00 .76677 .001005 .00020 780.50 .74176 .000789 .00020

140
U.S. Department of Commerce

Juanitn M. Kreps

Secretary,'

National Bureau of Standards

Ernest Ambler, UirciUir

Standard Reference Material 2014

Didymium Glass Filter for Checking the

Wavelength Scale of Spectrophotometers

Kenneth L. Eckerle and William H. Venable, Jr.

Serial Number:

This SRM is intended for use in calibrating the wavelength scale in the visible wavelength region of scanning

spectrophotometers having nominal bandwidths in the range 1.5 to 10.5 nm. Depending upon the bandwidth of

the spectrophotometer, anywhere from 14 to 24 wavelength corrections can be determined from 400 to 760 nm.

Detailed instructions on the use of this SRM and examples of its use are given in NBS Special Publication

260-66. Each didymium-glass filter is identified by the SRM number and a serial number.

The wavelengths of the transmittance minima as obtained from measurements on each filter are given in Table 1

.

These values are given for seven equally spaced values of the half-height width of triangular passbands. The

minima number is identified in the figure that illustrates the spectral transmittance as a function of wavelength.

The wavelength values of nine points of inflection on the spectral transmittance curve as obtained on three filters are given in Table 2. These inflection points are representative of the melt and are also identified in the figure.

These inflection points should only be used with the transmittance minima as described in Sections 2.2 and 2.3 in

The measurements on which these tables are based were made at 25 °C with a high-precision reference spectrophotometer that has a wavelength accuracy of 0.04 nm. Table 3 indicates the estimated random (as obtained

from 4 sets of measurements on a single filter) and systematic errors of the transmittance minima given in Table

I. Table 2 also indicates the range of the measured wavelengths of the inflection points. Trial calibrations made

on several instruments, using both minima and inflection points, indicate that wavelength corrections made with

these SRM's can be accurate to 0.2 nm. The uncertainty of a calibration, however, will depend upon the stability

and other characteristics of a particular instrument.

The technical and support aspects involved in the preparation, certification, and issuance of this SRM svere coordinated through the Office of Standard Reference Materials by R. K. Kirby.

The spectral transmittance as a function of wavelength for this filter is given in Table 4. These values are not

certified but are provided for use as specified in SP 260-66. They should not he used to check the photometric

scale of a spectrophotometer.

It is recommended that the filter be handled only by its edges and when not in use it should be stored in the box

provided. If cleaning is necessary, wet the filter with water and rub gently with optical lens tissue soaked with a mild soap solution, rinse with distilled water, rinse with isopropyl alcohol, and rinse again with distilled water. Dry after each rinsing by wiping lightly with optical lens tissue.

Washington, D.C. 20234 George A. Uriano, Chief

Januarys, 1980 (over) Office of Standard Reference Materials

SP 260-66.

141
Spectral transmi ttance of a typical didymium glass filter. Numbers

indicate the principal points of minimum transmittance and letters

indicate the principal points of inflection.

ct3m ^niii 142
TABLE 1

SRM 2014

Wavelengths (nm) of the transmittance minima

for the indicated bandwidths.

band h i dtm t.5nm 3.0nm 4 • 5nm 6.0nm 7.snm 9.0nm 10.5nm

Minimum no.

|__ h 02. 35 . .ip 1 . 6 8 m o i . 49 4 0 1. 36 h00 . 98 _ hqq.2

h

2 431.49 432.45

3 440.16 440.39 441.57 442.39 442.22 441.89 441.03

4 4MB. 63 445.17

5 472.70 472.57 472.93

6 478.80 479.25 479.20 478.26 477.35 476.51 475.66

7 513.42 513.59 513.87 514.30 515.39

8 529.63 530.10 529.99 529.53 529.31 529.15 528.91

9 572.67 573.23 574.17 575.05 576.50

10 585.31 585.52 585.76 586.02 585.99 585.36 584.43

11 623.63 624.03

12 629.42 629.38 628.51 626.97 626.98

13 684.67 684.70 684.74 684.75 684.73 684.68 684.60

14 739.90 739.96 740.24 740.90 741.99 742.94 743.63

15 748.27 748.08

143
Table 2

Wavelengths and Transmittances at Nine Selected

Points of Inflection

Point Wavelength Range* Transmittancet

Identification (nm) (nm)

A 406.38 +.08 0.7562

-.06

B 429.42 +.05 .7293

-.05

C 449.45 +.06 .6514

-.06

D 484.77 +.10 .6743

-.15

E 536.52 +.06 .5801 -.09

F 568.16 +.08 .4008

-.04

G 598.99 +.05 .3346

-.07

H 733.45 +.06 .4730

-.03

I 756.48 +.01 .4215

-.02

The range of wavelengths within which the wavelength for the given trans- mittance will fall for symmetric triangular passbands with half-height bandwidths from 1.5 to 10.5 nm. +

These values of transmittance are not certified.

SRM 2014

144
Table 3

Estimated Random and Systematic Errors of the Transmittance Minima

Band Number

1

2

3

4

5

6

7

8

9

10

II

12

13

14

15

Nominal

Wavelength

of Minimum

Transmittance

Standard Deviation for Indicated Bandwidth

1.5 nm 3.0 nm 4.5 nm 6.0 nm 7.5 nm 9.0 nm 10.5 nm

402 nm

431

440

446

473

479

513

530

573

585

624

630

685

740

748

0.015 nm

(0.07)1

0.013

(0.06)

0.021

(0.05)

0.023

(0.06)

0.01

1

(0.08)

0.015

(0.15)

0.022

(0.08)

0.012

(0.21)

0.004

(0.05)

0.007

(0.06)

0.058

(0.06)

0.210

(0.02)

0.019

(0.05)

0.009

(0.25)

0.020

(0.04)

0.018 nm

0.010

0.013

0.029

0.012

0.013

0.016

0.010

0.010

0.004

0.061

0.120

0.029

0.013

0.016

0.020 nm 0.021 nm 0.025 nm 0.029 nm

0.050

0.032

0.009

0.014

0.010

0.010

0.007

0.171

0.024

0.011

0.028

0 009

0.013

0.011

0.012

0.008

0.133

0.017

0.010

0.009

0.009

0.010

0.010

0.014

0.008

0.091

0.014

0.009

0.005

0.007 nm

(0.25)

0.014

0.011

0.007

0.017

(0.25)

0.010

(0.25)

0.007

(0.25)

0.014

0.009

0.012

(0.25)

0.010

(0.25)

tValucs in parentheses are estimates of the systematic error. The estimates for the 1 .5 nm bandw idth were obtained from the data taken at

1.5 nm intervals as compared to data taken at 0.15 nm intervals. The method of estimating the systematic errors for the 10 5 nm bandwidth

is described in Section 3.4 in SI' 260-66.

SRM 2014

145
TABLE 4

Transmittance (T) as a function of wavelength from 380 to 780.5 nm

for a bandwidth of 1.5 nm. The estimates of random and systematic

errors are also provided. These data are not certified.

SRM ?014

FTLTFR D3

WAVE- AT AT WAVE- AT AT

LENGTH STANDARD SYSTEM- LENGTH STANDARD SYSTEM-

(NM) T ERROR ATIC (NM) T ERROR ATIC

380.00 . 564P8 .000166 . 00020 381.50 . 589P7 .000158 .00020

383. 00 .61549 .000224 .00020 384.50 .6391

3

.000168 . 00020

386.00 .66074 .000036 .00020 387.50 .68019 .Ooome .00020

389.00 .70000 .000200 .00020 390. SO .71506 .000148 .00020

392.00 .73059 .000562 .00020 393. SO .741^9 .000126 .00020

395.00 .74008 .000371 .00020 396. SO .74605 .000431 .00020

398.00 .72008 .000147 .00020 399.50 .7071

1

.000209 .00020

401.00 .694^0 .000428 .00020 402. so .68362 .000087 .00020

404.00 .72360 .000381 .00020 405.50 .746^4 .000293 .00020

407.00 .76517 .000232 .00020 408.^0 .79309 .000365 .00020

410.00 .809S1 .000448 .00020 411.50 .81618 .000042 .00020

413.00 .82014 .000004 .00020 414.50 .82279 .000420 .00020

416.00 .82273 .000202 .00020 417. ^0 .823S5 .000148 .00020

419.00 .82484 .000191 . 00020 420.^0 .83133 .000174 .00020

422.00 .83041 .000209 .00020 423. SO .82769 .000173 .00020

425.00 .82973 .000208 .00020 426.50 .82916 .000229 .00020

428.00 .81332 .000144 .00020 429.50 .73002 .000429 .00020

431.00 .62838 .000289 .00020 432.50 .64134 .000161 .00020

434.00 .64801 .000081 .00020 435.50 .64135 .000088 .00020

437.00 .62778 .000179 .00020 438.50 .61104 .000166 .00020

440.00 .60400 .000144 . 00020 441.50 .60792 .000154 .00020

443.00 .61344 .000095 .00020 444.50 .60RS9 .000283 .00020

446.00 .60560 . 0001 68 .00020 447.50 .61992 .000148 .00020

449.00 .64707 .000144 .00020 U50.S0 .67304 .000572 .00020

452.00 .68938 .000140 .00020 453.50 .699S0 .000185 .00020

455.00 .7101

8

.000580 .00020 456. SO .71102 .000112 .00020

458.00 .698S1 .000144 .00020 459.50 .67728 .000053 .00020

461.00 .65876 .000163 .00020 462. SO .6501

1

.000161 .00020

464.00 .64916 .000003 .00020 465.50 .64446 .000051 .00020

467.00 .63254 .000032 .00020 468.50 .61760 .000171 .00020

470.00 .60380 .000282 .00020 471.50 .585H5 .000072 .00020

473.00 .57581 .000167 .00020 474.50 .597U8 .000313 .00020

476.00 .606Q3 .000204 .00020 477. K 0 .57178 .000297 .00020

479.00 .56222 .000147 .00020 480.50 .57066 .000315 .00020

482.00 .58701 .000180 .00020 483.50 .63200 .000305 .00020

485.00 .68802 .000153 .00020 486. SO .72015 .000144 .00020

488.00 .76019 .000431 .00020 489.50 . 787^6 .000137 .00020

491.00 .80846 .000352 .00020 492.50 .82013 .000444 .00020

494.00 .82381 .000270 .00020 495.50 .82173 .000711 .00020

497.00 .81535 .000042 .00020 498.50 .804P1 .0001 37 .00020

146
TABLE 4 (cont)

SRM ?014

FILTFR D3

WAVE- AT AT aT AT

LENGTH STANDARD SYSTEM- st Awn ARn systfm-

( MM) T ERROR ATIC T FRROR L. r\ r\ v n ATIC

500.00 .79105 .000313 • 00020 SOI .50 . 77626 .000087 .00020

503.00 .76044 .000093 .00020 504.50 .74601 .000161 .00020

506.00 .72982 .000217 .00020 S07.50 .70548 .000281 . 00020

509.00 .66187 .000082 . 00020 510.50 . 60232 . 0001 36 . 00020

512.00 .55353 .000145 .00020 513.50 .533^8 .000143 .00020

515.00 .55132 .000286 .00020 516. SO .58027 .000172 .00020

518.00 .59881 .000076 .00020 519.50 .60934 .000074 .00020

521.00 .59245 .000190 .00020 522.50 .52976 .000028 .00020

524.00 .45433 .000157 .00020 525.50 .42574 .000054 .00020

527.00 .41618 .000045 .00020 S28.50 .38625 .000279 .00020

530 .00 .379R4 .000030 .00020 531 .50 . 3891

1

.000143 . 00020

533. 00 .40520 .000141 .00020 534. 50 .46553 .000144 .00020

536. 00 • 55842 • 00QO71 .00020 S37 .SO . 6444

1

. 000079 .00020

539. 00 . 70722 .000036 .00020 540 • 50 .75790 .000133 .00020

542 .00 .79718 .000308 .00020 S43 . 50 . 823 Q 1 .000293 .00020

545.00 .84216 .000171 .00020 546.50 .854S5 . 000277 .00020

548.00 • 86261 .000159 • 00020 549.50 • 866S2 .000148 .00020

551 .00 . 86644 . 000?84 . 00020 552.50 , R6644 .000206 .00020

551. 00 . 86582 .000283 .00020 S55, 50 . 35479 . 000147 .00020

557.00 . 86138 . 0 0'/? 84 .00020 S58 .50 . 85472 .000169 .00020

560 .00 . 84UC7 . 0001 78 .00020 S61 .50 . 827^1 .000141 . 00020

563 .00 . 800S1 .000158 .00020 S64 . 50 .756^8 . 0001 77 .00020

566.00 .67427 .000053 .00020 567.50 .51342 .000165 .00020

569. 00 . 26737 .• 000287 v '.'V/ C I J ' . 00020 570 .50 , 08474 . 000010 .00020

572. OH . 0301

2

.000007 .00020 573. SO . 02986 .000009 . 00020

575.00 . 04042 .000006 .00020 S76. 50 . 04508 .000132 .00020

578.00 .05932 .000139 .00020 S79.50 .07972 .000139 .00020

581.00 .07928 .000270 .00020 582.50 .04534 .000138 .00020

58"+. 00 .01892 .000002 .00020 S85.50 .012^0 .000138 .00020

587.00 .01969 .000007 .00020 588. SO .03571 .000138 .00020

590.00 .05516 .000140 .00020 591. SO .06625 .000001 .00020

593.00 .08585 .onooii .00020 594. SO .1321

0

.000007 .00020

596.00 .20756 .000283 .00020 S97.S0 .285^4 .000140 .00020

599.00 .34273 .000058 .00020 ft00.50 .40063 .000052 .00020

602.00 .46448 .000280 .00020 603.50 .52727 .000164 .00020

605.00 .579^6 .000323 .00020 606.50 .61507 .000051 .00020

608.00 .63507 .000143 .00020 K09.SO .65418 .000081 .00020

611.00 .68840 .0*0165 .00020 612.50 .74187 .000092 .00020

614.00 .80164 .000424 .00020 615.50 .84914 .000364 .00020

617.00 .87574 .000173 .00020 S18.S0 .88S87 .000286 .00020

147
TABLE 4 (cont)

SRM 2014

FILTER P3

WAVE- AT aT W A\/r— AT aT

LENGTH ^T AMHARn O 1 H IV H r\ l J j I j i C 1

(

)

T TI 620 V? C v .• nnKJ KJ . rr5or -• nnm v KJ X no\J O - ft no?n 621 . RO . R7ft^7 Zj f r* ~ J Onn^l

4

ft ft ft Pft 693 . nn . O # f- *T *? . nnn? Aft • u u U u 07972 n n nti^n ft ft ft pft

626. nn .• R75n9 Kt 1 _/ KJ s . non?n 6P7 . ^n » ft7UQ^ . nnn 1 72 . ft ft ftpft

629. nn . R71 94 . n n n ? 4 n • uuucu ^3n • e;n . r>07000 r r rj

. n n n 1 qq - ft ftftpft

632 . nn . 87728 . nnn 1 56 633 . ^n . O O J »J . n n n 1 S7 . ft n ft pft

635 . nn • U O 7 C. J . n on 1 7u * ft nnpn f-ilf* - e:ft DQ1 Q(l - ft ft ft Of) • u u u c y

63ft. nn . 89372 . nnn343 * ft nnpft f*"^Q . Rft • CI y , ) r i \J - nnnss9 -•ftU ftU ftU cZ. Pftu 611 . 00 . 89773 . non4i7 . onn2n 642 . sn

' ftQ9P

1

. nnn6i r .00020

64.4,00 .90012 . 000439 . onn2n 645, 50 . 9no°i .• onm \> \J V JL 47*T f .00020

617 .00 .90140 .• nno33n kj KJ kj w ij . nnn?n 64ft . ^n » ft ft ft ft Aft . ooopo

650 .on .90110 . nooi 68 . nnn?n 651 . 50 . qnn9n . onni77 . nn02n

653. 00 .90175 . n n n 2 2 6 .• nnn?n "J ij C. l' 654 . sn • 9n2S9 . nnn943 . nno?n

656 l. / y-S KJ .W nnKJ KJ . 9n292 . nnnn75 .• fty Oft U U Pft f- v.* 657 - ^n . nnn c>A9 .• ftU ft\j ftPft \j C U

659 • nn . q n p ^ p . nno4i

9

. ft OOPft ftftft - ^ft . 9n 1 n

1

. n n n ^9

1

. ft n ft pn

662 I.I KJ C— .• nnKJ ' t • U - f KJ . nnn34n . nnn2n 663 . ^n % pq^ap . n n n 1 r 1 * ft ft ftpft

665. 00 . 89216 . nnm 63 . nnn2n 666 . ^n . Rft622 . nnnpn7 -• 000P0 y y y t y 668. V > KJ '-J 9 nnV • KJ . n n n ? 8

1

• ' ' . ' KJ C Kj . nnn?n m ^ft . R73n7 . n n n 1 ^7 . 000P0

671 .00 . nnn?4n . nnn?n ft7P . ^ft • O U *T X » nn n i 47 .O00PO

674 .00 .86150 onn 174 . o n n ? n 675. 5n - R56 r>3 . nnm 79 .00020 • KJ KJ KJ C K> 677. 0 0 • 84784 . n n 0 4 1

9

.• onn2n U I,1 I. *_J 678 • 50 .83564 . 0n0442 .00020 • kj yj yj c~ kj 680 .on . 821 12 . n 0 Q 1 4 8 .00020 681 .50 . 8041

R

. 000717 .00020 • yj yj " Cm yj 683 .00 .• 78494 1 KJ * ' ~ . n0f)624 . o n n 2 n 6ft4 . Rn . 77n42 . nn0R3i .00090 • uyu Cm kj 6K6 . n n . 7796R • u u ' ' a i. 6fl7 .RD - ft nft 1 7Q .• 000P0 u y u c. y

. R1 4P3 . o o n p 7 -• ftv OftU P ft t» 1,1 • R31 3R • ft n ft^ftP .00090 • kj kj \J Cm \J 692 .00 . 84679 . nnn583 • ft ft ft Pft 693 . FO . R62U6 * ft n ft pftS .00090 • KJ \J yj Cm KJ 69S .nn R7PQfl o " o • r> u 0017ft • uft n n ^ 1 u u U O 1

. ft ft ftpft • U U U c. KJ 698.00 .88812 .000377 .oon2o 699.50 .8931

3

.000211 .00020

701.00 .89612 .nnn738 .ooo2n 702.50 .897°3 .000246 .00020

704.00 .9on71 .n^n287 .00020 705.50 .90138 .000238 .00020

707.00 .90137 .000342 .00020 708.50 .901H1 .001539 .00020

710.00 .90232 .000587 .0on2o 711. so .90148 .000626 .00020

713.00 .90076 .000325 .00020 714.50 .89856 .000303 .00020

716.00 .895<n .000490 .00020 717.50 .89302 .000725 .00020

719.00 .88801 .000596 .00020 720.50 .88303 .000733 .00020

722.00 .87502 .000302 .00020 723.50 .86449 .000290 .00020

725.00 .85057 .000207 .00020 726.50 .830R3 .000568 .00020

728.00 .79900 .000638 .00020 729.50 .752^3 .000443 .00020

731.00 .68007 .000207 .00020 732.50 .56964 .000448 .00020

734.00 .42722 .000283 .00020 735.50 .287^9 .000281 .00020

737.00 .19664 .000288 . 00020 738.50 .16408 .000140 .00020

148
TABLE 4 (cont)

S3M 2014

^TLTF" H3

UJ A \/ F — A T A T A T aT

7> I rV M ' H r\ u ct a wn ARn

( mm 1 T1 rpp AD 'Mil A T T r j ATTT

7U n n n I *T u • u u 1 An ~*>f\ . iDU JU nnni (id

. U U U JL ^O .

1

I d""!) ARtlR . U l) U 1 J 1 . UUUc'J

743.00 .18770 .000565 .00020 744.80 .2131

8

.000296 .00020

746.00 .21285 .000145 .00020 747.^0 .19637 .000283 .00020

749.00 . 19647 .000144 . 00020 750.80 .22309 .000148 .00020

752.00 .26453 .000139 .00020 753.80 .313^2 .000169 .00020

755.00 .36843 .000151 .00020 756.50 .42908 .000425 .00020

758.00 .49007 .000140 .00020 759.50 .843P4 .000140 .00020

761.00 .58938 .000172 .00020 762.50 .627^5 .000474 .00020

764.00 .66334 .000105 .00020 765.50 .6961

7

.000171 .00020

767.00 .72629 .000162 .00020 768.50 .75118 .000288 .00020

770.00 .77113 .000^84 .00020 771.50 .78394 .000140 .00020

773.00 .79334 .000289 .00020 774.50 .79545 .000463 .00020

776.00 .79344 .000764 .00020 777.50 .783U2 .000858 .00020

779.00 .76568 . 009?68 .00020 780.50 .73923 .000091 .00020

149
U.S. Department of Commerce

Elliot L. Richardson,

Secretary

National Bureau of Standards

Ernest Ambler, Acting Director

^National ^nxtmx of jsttatutartte

(tferttftcate

Standard Reference Material 2030

Glass Filter for Transmittance Measurement

R. Mavrodineanu and J. R. Baldwin

Set # 70

This Standard Reference Material is intended as a reference source for one-point verification of the transmit- tance and absorbance scales of spectrophotometers at the given wavelength and measured transmittance. It consists of one glass filter in its holder and one empty filter holder. The filter bears an identification number.

For protection, the metal holder is provided with two shutters that should be removed during measurements.

The transmittance, T, at A 465.0 nm and for a spectral bandpass of 2.7 nm is: 0.3168 The cor- responding transmission density, —logioT, is: 0.4992

Date of Certification: January 1, 1981

The transmittance value (T) can be converted to percent transmittance (%T) by multiplying by 100. The trans- mission density is calculated from the measured transmittance (T). This value should be indicated by the absorbance scale of the spectrophotometer if the filter is measured against air.

The transmittance value given was measured against air at an ambient temperature of 23.5 0 C, and is estimated

to be accurate to within ±0.5 percent at the time of certification. This uncertainty includes the random and

systematic errors of the calibration procedure, as well as transmittance changes of the filter during the period of

calibration.

It is possible that aging of the glass may cause some filters to change transmittance by about ±1 percent over a period of approximately 1 year from the date of calibration. Improper storage or handling of the filter may also cause changes [5]. In cases where verification is desirable, the filter should be returned to the National Bureau of

Standards for cleaning and recalibration.

It is recommended that the filter in the holder be handled only by the edges and with soft plastic (polyethylene)

gloves and optical lens tissue. When not in use, it should be stored in its holder, with the shutters on, and in the box provided for this purpose. Extended exposure to laboratory atmosphere and dusty surroundings should be

avoided.

This Standard Reference Material was issued with the assistance and advice of K. D. Mielenzand J. R. DeVoe.

The technical and support aspect involved in the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by R. W. Seward.

Washington, D.C. 20234 J. Paul Cali, Chief

September 23, 1976 Office of Standard Reference Materials

(over)

150
The transmittance measurements were made using the high-accuracy spectrophotometer designed and built at the Institute for Materials Research, National Bureau of Standards [ 1 ]. This instrument represents the primary

transmittance standard; its transmittance accuracy was established using the double-aperture method of

linearity testing [1,3,5,6]. The reproducibility (relative standard deviation obtained from a set of 20 measurements) of this high-accuracy spectrometer for transmittance measurements on glass filters similar to the one

used to produce this SRM, is approximately 0.02 percent.

The combined uncorrected systematic error of the instrument is estimated to be not more than ±10 4 transmittance units. As indicated on the face of this certificate, SRM 2030 is intended to be used as a one-point verification of the transmittance (absorbance) scales of spectrophotometers. If these scales require verification at other wavelengths and transmittances, "Glass Filters for Spectrophotometry," SRM 930c or subsequent issues, should be

used.

The neutral glass for the filter was provided by Schott of Mainz, Germany, and is designated as "Jena Color and

Filter Glass " [2,5].

The exposed surface of the glass is approximately 29 X 8 mm, measuring from a point 1.5 mm above the base of

the filter holder (see figure). The empty filter holder is provided to be used in the reference beam of the spectrophotometer so that approximately equivalent conditions of stray radiations are achieved for both beams.

The transmittance of the filter depends upon the intrinsic properties of the material, spectral bandpass, wavelength, geometry of the optical beam, temperature, and positioning of the filter. A change of ambient temperature of 1 or 2 °C from 23.5 °C will not significantly affect the calibration [5].Changes in the transmittance maybe

caused by surface conditions, aging of the glass, exposure to a harmful atmosphere, or careless handling as indicated on the face of this certificate [2,3,4,5]. The effective spectral bandpass used to determine the certified value is given on the face of the certificate and the transmittance measurements are made by producing the

vertical image of the slit (about 8 mm by 0.5 mm), using a convergent beam geometry with an aperture ratio f:10, in the middle of the entrance face of the glass filter. The filter was measured in the spectrophotometer in a position perpendicular to the incident light beam as shown in the attached figure.

Prior to certification measurements, the filter was examined for surface defects and thoroughly cleaned [5]. Should the surface of the glass filter become contaminated, no attempt should be made to clean it unless the user has the facilities to demonstrate that the cleaning treatment has not altered the glass surface or degraded the accuracy of the certified value. Because the Standard Reference Material is a transfer standard, the only means

available to verify its integrity is remeasuring its transmittance with a primary standard instrument similar to that used in this certification [1,4,5]. In most cases where verification, or recertification, of the transmittance

value is desirable, it will be most expeditious to return the filter to the National Bureau of Standards for measurement. Prior to shipment the NBS Office of Standard Reference Materials should be contacted regarding the conditions and cost of verification and /or recertification. REFERENCES

[1] R. Mavrodineanu, An Accurate Spectrophotometer for Measuring the Transmittance of Solid and Liquid

Materials, NBS Journal of Research 76A, No. 5, 405-425 (1972).

[2] R. Mavrodineanu, Solid Materials to Check the Photometric Scale of Spectrophotometers, NBS Tech.

Note 544, O. Menis and J. I. Shultz, ed., pp 6-17, U.S. Government Printing Office, Washington, D.C.

20402 (Sept. 1970), ibid NBS Tech. Note 584, pp 2-21 (December 1971).

[3] K. S. Gibson, Spectrophotometry, NBS Circ. 484 (Sept. 1949).

[4] Collected Papers from NBS Conference on Accuracy in Spectrophotometry and Luminescence Measurements, NBS Journal of Research 76A, No. 5, 375-510 (1972).

[5] R. Mavrodineanu and J. R. Baldwin, Glass Filters as a Standard Reference Material for Spectrophotometry-Selection, Preparation, Certification, Use SRM 930, NBS Special Publication 260-51, U.S. Government Printing Office, Washington, D.C. 20402, (1975).

[6] K. D. Mielenz and K. L. Eckerle, Spectrophotometric Linearity Testing Using Double-Beam-Aperture

Method, Appl. Optics, 11, 2294-2303 (1972).

151
METAL HOLDER FOR THE COLORED GLASS FILTERS

METAL HOLDER

57 X 13 X 13

EXPOSED FILTER SURFACE

29 X 8

COLORED GLASS FILTER

30.5 X II X 2.0 (Of 1.5)

1.5

DIMENSIONS IN I

152
U.S. Department of Commerce

Juanita M. Krepa

Secretary

National Bureau of Standards

Ernest Ambler, Director Rational ^mtmx of j^iandartb

(Eerttftcate

Standard Reference Material 2031

Metal-on-Quartz Filters f or S pectrophotometry

R. Mavrodineanu and J. R. Baldwin

This Standard Reference Material is intended for use in the verification of the transmittance and absorbance

scales of spectrophotometers in the ultraviolet and visible spectral regions. It consists of three individual filters

in their metal holders and one empty filter holder.

Each filter is made from two non-fluorescent fused silica plates, one of which carries a semi-transparent

evaporated chromium metal layer while the other is clear. The two plates comprising the filter are assembled by

optical contact. The chromium coating on two of the filters produces nominal transmittances of 10 percent and

30 percent. The third filter is made from assembling two clear fused silica plates by optical contact, and has a nominal transmittance of 90 percent. The metal holders for these filters are provided with shutters to protect the

filters when not in use. These shutters must be removed at the time of measurement and be replaced after the measurements have been completed. Each filter bears an identification number.

Filter & Set

Ident. Number

TRANSMITTANCE (T)

Wavelength, nm

250.0 280.0 340.0 360.0 400.0 465.0 500.0 546.1 590.0 635.0

20-10

20-30

20-90

0.1232

0.4314

0.9132

0.1176

0.4176

0.9203

0.1085

0.3809

0.9273

0.1087

0.3736

0.9282

0.1069

0.3593

0.9301

0.0990

0.3267

0.9323

0.1004

0.3185

0.9330

0.1083

0.3206

0.9334

0.1179

0.3311

0.9338

0.1284

0.3432

0.9343

Filter & Set

Ident. Number

TRANSMITTANCE DENSITY (-logioT)

Wavelength, nm

250.0 280.0 340.0 360.0 400.0 465.0 500.0 546.1 590.0 635.0

20-10

20-30

20-90

0.909

0.3651

0.0394

0.930

0.3792

0.0361

0.965

0.4192

0.0328

0.964

0.4276

0.0324

0.971

0.4445

0.0315

1.004

0.4859

0.0304

0.998

0.4969

0.0301

0.965

0.4940

0.0299

0.928

0.4800

0.297

0.891

0.4645

0.0295

Date of Certification: January 1, 1981

Washington, D.C. 20234 George A. Uriano, Chief

June 1, 1979 Office of Standard Reference Materials

(over)

153
The transmittance values (T) can be converted to percent transmittance (%T) by multiplying by 100. The

transmittance densities are calculated from the measured transmittance (T). The transmittance densities should

be indicated by the absorbance scale of the spectrophotometer if the filters are measured against air. The

transmittance values given were measured against air at an ambient temperature of 23.5 °C.

The transmittance values for the filter with a nominal transmittance of 10 percent are estimated to be accurate to within ± 1.0 percent at the time of certification. The transmittance values for the filters having a nominal

transmittance of 30 percent and 90 percent are estimated to be accurate to within ±0.5 percent at the time of

certification. This uncertainty includes the effects of random and systematic errors of the calibration procedure,

as well as possible transmittance changes of the filters during the period of calibration.

Aging of the material may cause some filters to change transmittance with time. Improper storage or accidental

touching of the filter surface may also cause changes.

When not in use, the filters should be stored in their holders with the shutters in place and in the metal container

provided for this purpose. Extended exposure to laboratory atmosphere and dirty surroundings should be

avoided. In cases where verification is desirable, the filters should be returned to the National Bureau of

Standards for cleaning and recalibration. It is advisable to perform the verification on a yearly basis.

The transmittance measurements were made using the high-accuracy spectrophotometer designed and built at the NBS Center for Analytical Chemistry [1]. This instrument represents the primary transmittance standard;

its transmittance accuracy was established using the double-aperture method of linearity testing [1,3,5,6]. The

estimated standard deviation obtained from a set of 20 measurements of the high-accuracy spectrophotometer

used for transmittance measurements on filters of the SRM 2031 type is 5 x 10

5 transmittance units for transmittance between 0. 1 and 0.3. The bounds of the systematic error of the instrument are estimated to be

± 10 transmittance units.

The transmittance, T, was measured against air in the reference beam; hence it includes the reflection losses that occur at the air-filter interface. Under these circumstances the measured transmittance, T, has a corresponding

transmittance density, defined as -logio T. The internal transmittance, T, of a material is defined as the transmittance of the material corrected for reflection losses. This is obtained experimentally when the measure- ments are made against a blank sample in the reference beam. The absorbance, A, of a material is related to this internal transmittance, T, by the expression, A = -logioT. The transmittance measurements are made by

producing the vertical image of the slit (about 8 mm by 0.5 mm), using a convergent beam geometry with an

aperture ratio f:10, in the middle of the entrance face of the filter. The filters were measured in the spectrophotometer in a position perpendicular to the incident light beam.

The metal-on-quartz filters which constitute this SRM were produced according to NBS specifications by

Cosmo Optics, Inc., Middletown, New York. The quartz plates were produced from non-fluorescent fused silica material of optical quality, ground and polished to produce an optical contact. The metal used to produce, by

evaporation, the semi-transparent metal coating was chromium, obtained through the van Arkel process, and

has an indicated purity of 99.998 percent. It was provided by The Atomergic Chemetals Co., Plainview, New

York. The fused silica plates were ground and polished at the same time and on the same grinding wheel, each to the nominal dimensions: 1.5 mm thick, 30.5 mm long, and 10.4 mm wide.

The exposed surface of each filter is approximately 29 x 8 mm, measuring from a point 1.5 mm above the base of

the filter holder (see figure). The empty filter holder provided is to be used in the reference beam of the spectrophotometer so that approximately equivalent conditions of stray radiation are achieved for both beams.

The transmittance of the filters depends upon the intrinsic properties of the material, wavelength, spectral

bandpass, geometry of the optical beam, temperature, and positioning of the filter. A change of ambient

temperature of 1 or 2 °C from 23.5 °C will not significantly affect the calibration [5]. Changes in the transmittance may be caused by surface conditions, aging of the material, exposure to a harmful atmosphere, or

careless handling [2,3,4,5].

SRM 2031 is stored in a black anodized aluminum container provided with a threaded cap made of the same

metal. Each filter is placed in a cylindrical cavity to prevent any contact between the filter face and the walls of

the storage container. Contamination of the filter surface with particulate matter due to static charges is minimized through the metallic nature of the container. A flat leaf spring is inserted into the cylindrical cavity

with each filter holder to minimize damage during transportation. These springs can be removed during normal

use in the laboratory.

154
The filter is shown in the assembled unit with its front surface facing up. The filter, in its filter holder, should be

placed in the cuvette compartment of the spectrophotometer with its front surface facing the incident light beam

and the rear surface facing the photodetector.

Top: Cylindrical container with its screw cap, both made of black-anodized aluminum alloy. Four filter holders

can be stored in the cylindrical container. Bottom (from left to right): Aluminum alloy filter holder, 12.5 mm

square and 58 mm high; Metal-on-quartz filter; Retaining spring of beryllium-copper with nylon screw and

washer; Assembled unit; and Two Delrin shutters. All metal and plastic parts are flat black.

155
Prior to certification measurements, each filter was examined for surface defects and the condition of the optical contact [5]. Should the surface of the filter become contaminated, no attempt should be made to clean it unless the user has the facilities to demonstrate that the cleaning treatment will not alter the surface or degrade the accuracy of the certified values. As SRM 2031 is a transfer standard, the only means available to verify its integrity is to remeasure its transmittance with a primary standard instrument similar to that used in this certification [1,5]. In most cases, where verification or recertification of the transmittance values is desirable, it

will be most expeditious to return the filters to the National Bureau of Standards for measurement. Prior to shipment, the NBS Office of Standard Reference Materials should be contacted regarding the conditions and

cost of verification and /or recertification.

Further information concerning the selection, preparation and properties of SRM 2031 will be found in reference 5.

This Standard Reference Material was issued with the assistance and advice of K.D. Mielenz and I.L. Barnes.

The technical and support aspects involved in the preparation, certification, and issuance of this Standard

Reference Material were coordinated through the Office of Standard Reference Materials by R.W. Seward.

We wish to acknowledge the cooperation of George N. Bowers, Jr., M.D., of Hartford Hospital, Hartford,

Connecticut; Royden N. Rand, Ph.D., of the Eastman Kodak Co. Research Laboratories, Rochester, New

York; and Donald S. Young, M.D., Ph.D., of the Mayo Clinic, Rochester, Minnesota.

The contributions of H.E. Bennett and J.M. Bennett of the Michelson Laboratory, Physical Optics Branch,

Naval Weapons Center, China Lake, California, who helped in the production of SRM 203 1 are also gratefully

acknowledged.

References

1 . R. Mavrodineanu, An Accurate Spectrophotometer for Measuring the Transmittance of Solid and Liquid

Materials, NBS Journal of Research 76A, No. 5, 405-425 (1972).

2. R. Mavrodineanu, Solid Materials to Check the Photometric Scale of Spectrophotometers, NBS Tech. Note

544, O. Menis and J.I. Shultz, Eds., pp. 6-17, U.S. Government Printing Office, Washington, D.C. 20402

(Sept. 1970); ibid, NBS Tech. Note 584, pp. 2-21 (December 1971).

3. K.S. Gibson, Spectrophotometry, NBS Circ. 484 (Sept. 1949).

4. R. Mavrodineanu, Considerations for the Use of Semi-transparent Metallic Thin Films as Potential Transmittance Standards in Spectrophotometry. NBS Journal of Research 80A, No. 4, 637-641 (1976).

5. R. Mavrodineanu and J.R. Baldwin, Metal-on-Quartz Filters as a Standard Reference Material for Spectrophotometry, SRM 2031. NBS Special Publication 260-68, U.S. Government Printing Office,

Washington, D.C. 20402, 1979.

6. K.D. Mielenz and K.L. Eckerle, Spectrophotometer Linearity Testing Using the Double-Aperture Method,

Appl. Optics 11, 2294-2303 (1972).

156
. S. Department of Commerce

Philip M. Klutznick

Secretary

National Bureau of Standards

Ernest Ambler, Director

^National ^ureatt of jitartrtartta

Certificate

Standard Reference Material 2033

Crystalline Potassium Iodide with Attenuator

Heterochromatic and Isochromatic Stray Radiant Energy

Standard for Ultraviolet Absorption Spectrophotometry

K. D. Mielenz and R. Mavrodineanu

This Standard Reference Material consists of reagent-grade crystalline potassium iodide (KI) and a radiation attenuator

to be used to assess the heterochromatic stray radiant energy (stray light) in ultraviolet absorption spectrophotometers in the spectral region below 260 nm.. The radiation attenuator consists of two semitransparent evaporated metal-on-fused

silica (non-fluorescent) filters, each having a nominal transmittance of 10%. One filter is mounted in a cuvette-style

holder that can be inserted into the sample compartment of the spectrophotometer. The other is mounted in one of the two shutters of the holder. The use of this attenuator permits the expansion of the transmittance scale into the lowtransmittance region by providing a two-step attenuation of the reference beam of the spectrophotometer to about 1%.

The attenuator can also be used to assess isochromatic stray light by following the instructions given in this certificate.

The heterochromatic stray light is assessed by measuring the spectral absorbance of aqueous solutions of SRM 2033 ol known pathlengths and concentrations, and comparing the results with the certified values of the specific absorbance, e.

Specific Absorbance'

6(Lg" cm '), vs Wavelength, A (nm), at 23.5 °C

k 240 245 250 255 260 265 270 275

e 25.6 10.67 3.66 1.05 0.260 0.0560 0.0121 0.003

1

'"Specific Absorbance" is defined here as absorbance per unit pathlength and unit concentration. The term "absorptivity" has been avoided since it is ambiguously defined. See K D. Mielenz, Anal. Chem. 48, 1093-1094 (1976)

The estimated uncertainty of these values is ± 5%, which includes the random and systematic errors of the calibration

procedure, as well as variations due to possible instability of the KI. (See Certification Procedure.)

The material used to produce SRM 2033 was obtained from the J.T. Baker Chemical Co., Phillipsburg, N.J., in two

bottles, as reagent-grade (99.8% purity) potassium iodide.

The transmittance of the filter mounted in the holder at A255 nm is ; the transmittance of both filters at A.255 is . SRM 2033 was issued with the technical assistance of J. R. Baldwin, R. W. Burke, A. L. Cummings, B. I. Diamondstone,

and G. A. Sleater, and under the overall direction of E. L. Garner, NBS Inorganic Analytical Research Division.

The technical and support aspects concerning preparation, certification, and issuance of this SRM were coordinated

through the Office of Standard Reference Materials by R. W. Seward.

Washington, D.C. 20234 George A. Uriano, Chief

May 9, 1980 Office of Standard Reference Materials

(over)

157
Potassium Iodide Material Testing:

Material homogeneity was tested by measuring the absorbance of 1% aqueous solutions of the KI sampled from the

top, middle, and bottom of each bottle. These measurements, at 265, 267, and 270 nm, showed no evidence of

inhomogeneity. Tests for moisture content (Karl Fischer method) gave an average of 0.007%. This value was sufficiently

small that all certified data are based on weighed samples of the undried, as received, material.

Stability of the material to UV and visible light was tested by exposing the KI salt in a low-actinic glass bottle to radiation

from a 3 kW xenon-arc lamp at a distance of 25 cm for four days at room temperature. The average absorbances at five wavelengths between 240 and 270 nm of aqueous solutions of the exposed material were 1.1% lower than those of

solutions of the unexposed material. In view of the severity of this test, this change was considered minor. Nonetheless,

the 1.1% was included in the overall uncertainty of the certified values.

Potassium Iodide Certification Procedure:

The certified specific absorbances were measured in the NBS Center for Analytical Chemistry high-accuracy spectrophotometer [1,2], equipped with a deuterium lamp and UV averaging sphere [3,4]. Thirteen aqueous solutions of KI

with concentrations ranging from 0.03 to 30 g L ' were prepared and measured against distilled water, using standard

fused-silica cuvettes with pathlengths between 10.001 and 10.009 mmb

. The absorbance measurements were performed

at the temperature, t = 23.5 ± 0.5 °C. A 0.2 nm bandpass was used, and wavelength settings were made with an accuracy

of 0.05 nm. The measurements were made on at least three concentrations at each wavelength. These concentrations were

chosen so that most absorbance readings fell between 0. 1 and 1 .0 to minimize stray light and bandwidth errors. The data were found to obey Beer's law.

Thus, the equation,

e = A/cJ, (1)

was used to calculate the specific absorbances, e, from the measured absorbances, A, and the known values of concentration, c, and pathlength, I .

Limits to random error (two standard deviations) of these measurements (including the photometric imprecision of the spectrophotometer, errors in the repositioning of cuvettes, concentration errors, pathlength uncertainties, temperature

errors, Beer's law uncertainties, and bandwidth errors) were determined to be ± 2.4%. The error due to the 0.05 nm

uncertainty of the wavelength calibration of the spectrophotometer is ± 1.1%.

The uncertainty of 5% stated on the face of this certificate represents the sum of these errors and the above mentioned

1.1% uncertainty due to instability of the KI. No corrections were applied for the effects of internal reflections inside the sample and reference cuvettes, nor were the weights corrected to vacuum. These and all other sources of error were

considered negligible.

The temperature coefficient at 260 nm was determined to be

- • ^ = 0.031 °C

_1

. (2)

e dt

For precision measurements, it is recommended that SRM 2033 be used in thermostated cuvettes at 23.5 °C, or that a temperature correction according to Eq. (2) be applied.

h lssued by NBS as SRM 932, Quartz Cuvette for Spectrophotometry.

SRM 2033

Page 2

158
Instructions for Use of Potassium Iodide

Storage and Preparation:

SRM 2033 should be stored in the original, low-actinic glass bottle and the cardboard container in which it was issued

to protect it from unnecessary exposure to light and humidity. When so stored, the expected stability of this material is at

least three years. Thus, until additional stability data are obtained, this material should be used within three years of the date of purchase.

All solutions prepared from SRM 2033 should be made in borosilicate glass containers using distilled water and transfer

pipettes (Pasteur type) of the same glass and fitted with rubber bulbs

0

. Use clean spectrophotometer cuvettes, free of

scratches, made of non-fluorescent fused silica, and fitted with ground-glass or Teflon stoppers to minimize evaporation;

or preferably use NBS SRM 932. Mark all cuvettes to assure the same orientation in the spectrophotometer, and place

them into their respective holders. Using transfer pipettes of the type mentiond, rinse each cuvette several times with

distilled water. Prepare a solution of KI in distilled water (e.g., 1%), fill the sample cuvette with the KI solution and the reference cuvette with distilled water. Measure the absorbance, leaving the cuvettes in their holders, empty them (using the pipettes), and repeat the rinsing and filling operations until constant absorbance readings are obtained. Fresh

solutions should be made before every test.

Measurements:

A 1% KI solution (c = 10 g L ') with a 1 cm pathlength exhibits a sharp cutoff in transmittance near 260 nm; i.e., it transmits more than 90% above 273 nm, but less than 0.01% below 258 nm. Therefore, with the monochromator set for a wavelength below 260 nm, any appreciable amount of light detected is heterochromatic stray light, which consists of

wavelengths above the cutoff. The amount of stray light in the spectrophotometer at wavelength X may be determined

from the equations:

T(X) + x(X) (3) T'(X) =

x(X) =

where:

1 + x(X)

T'(X) - T(X) (4)

1 - T'(X)

x(X) is the stray light ratio,

T'(X) is the apparent transmittance,

T(X) is the true transmittance.

The stray light ratio, x(X), is the proportion of heterochromatic stray radiant energy in the spectrophotometer for the wavelength setting X. Equation (4) forms the theoretical basis for the determination of the stray light ratio by comparing

apparent transmittance to true transmittance. For SRM 2033, the true transmittance, T(X), of KI solutions may be

calculated as:

T(X)= 10-'<A,c£

where e(X) is the certified specific absorbance given on the face of this certificate.

v Soft glass containers and pipettes contain residual amounts of UV absorbing material, but can be used after proper cleaning. Several rinses, first with

isopropyl alcohol and then with distilled water, are generally adequate.

SRM 2033

Page 3

1 59
The apparent transmittances of KI solutions depend not only on the stray light ratio of the spectrophotometer, but also on the wavelength accuracy and the spectral bandwidth, which can significantly affect the results obtained because of

the steep slope of the absorbance cutoff of KI. A low-pressure mercury discharge lamp is suggested for verifying the

wavelength scale, and a bandwidth as narrow as compatible with adequate signal-to-noise ratios should be used.

Optical Attenuator: Many instruments do not permit the direct measurement of transmittances below certain limits, e.g., 1% or 0. 1%. To

measure stray light ratios below these limits, the reference beam of the spectrophotometer must be attenuated to extend

the transmittance scale into the low-transmittance region.

As mentioned on the face of this Certificate, the optical attenuator consists of two filters, each of which has a nominal

transmittance of 10 percent. One filter is mounted in a metal holder that can be inserted in the sample compartment of

the spectrophotometer (5). This holder is provided with a front and rear shutter, one of which has a window in which the

second filter is mounted. The holder and shutters are flat black. This unit was produced in the NBS Instrument Shops.

Instructions for Use of the Attenuator

This unit can be used to attenuate the incident radiation in the reference beam of the spectrophotometer in two steps

by a total factor of about 100, corresponding to about 1 percent transmittance (6). To attenuate by a factor of 10, the attenuator is inserted in the sample compartment of the spectrophotometer facing the incident beam, with both shutters removed. A further attenuation by a factor of about 10 is obtained when the shutter carrying the second filter is inserted

in the holder, in front of the first filter. Under these conditions, and with an instrument that cannot measure trans- mittances lower than 1 percent, the use of the attenuator will permit heterochromatic stray light to be measured down to about 0.01 percent. This attenuation procedure can be used with spectrophotometers capable of scale expansion.

Isochromatic Stray Light:

The radiation attenuator can be used to assess the isochromatic stray light that results from reflection of the incident

radiation at the surface of the sample and various optical components, and reaches the photodetector without passing

through the sample. It is implicitly assumed that the sample compartment of the spectrophotometer is light-tight.

The measurement is performed by placing the attenuator in the sample beam of the spectrophotometer, with the opaque shutter placed at the rear of the filter holder. Under these conditions, if a signal is detected, it is caused by

reflection at the surface of the filter exposed to the incident radiation. This radiation is scattered from the walls and other

components of the sample compartment and reaches the photodetector without passing through the sample (5). This

signal is the isochromatic stray light.

Isochromatic stray light, which passes through the sample, is generally caused by interreflections between lenses and/ or

other sample compartment elements. Tests for this stray light component, which is not detected by the methods described

above, are discussed in references 7 and 8.

References:

1. R. Mavrodineanu, J. Res. NBS 76A, 405-425 (1972).

2. J. F. Barkley, F. C. Ruegg, and R. Mavrodineanu, 29th Pittsburgh Conf., Abstract 452, Cleveland, Ohio, (1978).

3. K. D. Mielenz, R. Mavrodineanu, and E. D. Cehelnik, J. Res. NBS 78A, 631-635 (1974).

4. K. D. Mielenz, R. Mavrodineanu, and E. D. Cehelnik, Appl. Optics 14, 1940-1947 ( 1975).

5. R. Mavrodineanu, J. Res. NBS 80A, 637-641 (1976).

6. Estimating Stray Radiant Energy, ASTM Manual on Recommended Practices in Spectrophotometry, pp. 94-105,

3rd. Edition, 1969, 1916 Race St., Philadelphia, Pa. 19103.

7. K. D. Mielenz, J. Res. NBS 76A, 455-467 (1972).

8. K. D. Mielenz and R. Mavrodineanu, J. Res. NBS 77A, 699-703 (1973).

SRM 2033

Page 4

160
U. S. Department of Commerce

Frederick Dent

Secretary

National BursaB of Standards

Richard W. Kpberts, Director Rational ^Buram rxi j^tandartfe

(Eertifttate

Standard Reference Material 2203

Potassium Fluoride

(Standard for Ion-Selective I Electrodes)

E. S. Etz

This Standard Reference Material, certified for the activity of fluoride ion in solutions of this

salt, is made available for the standardization of fluoride ion-selective electrodes. The material is of

analytical reagent-grade purity, but should not be considered entirely free of traces of chloride,

fluosilicates and heavy metals. Potentiometric measurements on solutions of this material

employing fluoride ion-selective electrodes in cells without liquid junction indicate this material to be homogeneous within the precision (± 0.003 pF unit) of the measured potential of the fluoride

ion-selective electrode. Chemical analysis of this material indicates a minimum assay of 99.5 percent

KF after drying.

This material is certified for the activity coefficient of fluoride ion and the related value of pF

(=—log aF

-, where ap - is a conventional activity of fluoride ion) at 25 °C for solutions of potassium

fluoride over the range of molalities m = 0.0001 to m = 2.0. Certified values of - and pF(S) at selected molalities are found in the table on the reverse page. The pF(S) values given are estimated

to be accurate to ± 0.01 pF unit.

The mean molal activity coefficient of potassium fluoride from m = 0.0001 to m = 2.0 may be

represented at 25 °C by the equation:

A

1/2

log y+ =—TMl .+ 0 m + Cm2 _ 1+Bm 1 ' 2

where m is the molality. The numerical values of the constants appearing in this expression are, at 25 °C:

A = 0.5108

B = 1.2880

'31= 2.7843 x 10- 2 C = 4.6933 x 10- 3

The overall direction and coordination of the technical measurements leading to certification were performed under the chairmanship of R. A. Durst.

The technical and support aspects involved in the preparation, certification, and issuance of this standard reference material were coordinated through the Office of Standard Reference Materials

by T. W. Mears.

Washington, D. C. 20234 J. Paul Cali, Chief

May 21 , 1973 Office of Standard Reference Materials

161
Values of 7±

calculated from the relation given above represent the most reliablv known experimental activity coefficient data to an uncertainty of no larger than ± 0.005 in the value of y + over

the range of molalities indicated.

Certified Values of Ionic Activity (ay-$ Single Ion Activity

Coefficients (yy~) and Standard Values of

pF (=-log ay- for Fluoride Ion at 25 °C

(all referred to the molality scale)

Fluoride

KF Ion Activity Activity

Molality Molarity Concentration* Coefficient PF (S)

(m) (c) (g/1) 7K -=

7K+ -7+ a F- = a K

+ = a±

0.000

1

0.0000997 0.00189 0.988 0.0000988 4.005 0.0005 0.000499 0.00947 0.975 0.000487 3.31 2 0.001 0.000997 0.0189 0.965 0.000965 3.01 6 0.005 0.00498 0.0947 0.927 0.00464 2.334 0.01 0.00997 0.1893 0.902 0.00902 2.045 0.05 0.0498 0.9463 0.818 0.0409 1.388 0.1 0.0996 1.892 0.773 0.0773 1.11 2 0.2 0.1990 3.781 0.726 0.145 0.838 0.3 0.2982 5.665 0.699 0.210 0.6 78 0.5 0.4961 9.425 0.670 0.335 0.475 0.75 0.7424 14.104 0.652 0.489 0.31i

1.0 0.9873 18.757 0.645 0.645 0.1

9

0 1.5 1.4729 27.983 0.646 0.969 +O.OI4

2.0 1.9523 37.091 0.658 1.316 -0.1

1

9

*To convert to parts per million (mg/1) multiply by 103

The equation relating the mean molal activity coefficient to molality may be used to calculate

values of pF at concentrations other than those appearing in the table. The convention used here for

the assignment of ionic activities in solutions of potassium fluoride is based on hydration theory

and is described by Robinson, Duer and Bates [Anal. Chem. 43, 1862(1971)]. For this particular

1:1 electrolyte, the convention leads to 7 F- =7 K

+ in aqueous solution, and values of ay- are therefore obtained by the relation

ay-~ myy- = 1117 +

Preparation of Standard Solutions

To prepare a 1.0 molal solution, transfer 57.363 g of potassium fluoride (weight in air) to a

1 liter volumetric flask. Dissolve and fill to the mark with distilled water at 25 °C. The distilled water should have a conductivity no greater than 2 x 10 6

J2 '. The potassium fluoride is hygroscopic and should be dried in two consecutive stages; initially for a period of 2 hours at 110 °C,

followed by drying at 200 ± 10 °C for an additional 2 hours. After drying, normal precautions

should be exercised to prevent pickup of moisture, i.e., minimal exposure to humid conditions prior

to and during weighing.

162
Similarly, a 0.1 molal solution may be prepared by the transfer of 5.786 g of potassium fluoride

(weight in air) to a 1-liter volumetric flask, dissolving, and diluting to the mark with distilled water

at 25 °C. Appropriate dilution of either standard solution should be used to obtain standards in the

concentration range of interest to the user.

After preparation, standard solutions should be transferred to non-silicate storage containers,

e.g., polyethylene bottles, to avoid fluosilicate formation and the resulting decrease in fluoride ion

activity.

Electrode Calibration

In order to minimize residual liquid junction potential errors arising at the reference electrode

junction, it is recommended that reference standards be used at concentrations similar to those of

the samples. Also, the use of a bracketing technique, whereby two standard solutions bracket the

concentration range of the samples, will increase the reliability of the measurements by minimizing

errors due to non-Nernstian electrode response.

163
U.S. Department ot Commerce

'luanita M. Kreps

Secretary

National Bureau ot Standards

Krnest Amhler. Director

Rational ££ttram of jgftanrlartte

(Eerttftcate

Standard Reference Material 2032

Crystalline Potassium Iodide

Heterochromatic Stray Radiant Energy Standard for

Ultraviolet Absorption Spectrophotometry

K. D. Mielenz and R. Mavrodineanu

This Standard Reference Material consists of reagent-grade, crystalline potassium iodide (KI) to be used to

assess heterochromatic stray radiant energy (stray light) in ultraviolet absorption spectrophotometers in the

spectral region below 260 nm. Stray light is assessed by measuring the spectral absorbance of aqueous solutions

of S R M 2032 of known pathlengths and concentrations, and comparing the result with the certified values of the

specific absorbance, t.

Specific Absorbance

3

e (L g" 1 cm"

1 ), vs Wavelength, A (nm), at 23.5 °C

A 240 245 250 255 260 265 270 275

e 25.6 10.67 3.66 1.05 0.260 0.0560 0.0121 0.0031

a "Specific absorbance" is defined here as absorbance per unit pathlength and unit concentration. The term "absorptivity" has been avoided

since it is ambiguously defined. See K. D. Mielenz, Anal. Chem. 4JL 1093-1094 (1976).

The estimated uncertainty of these values is ± 5%, which includes the random and systematic errors of the

calibration procedure, as well as variations due to possible instability of the KI. (See, Certification Procedure.)

The material used to produce SRM 2032 was obtained from the J. T. Baker Chemical Co., Phillipsburg, N.J., in two bottles, as reagent-grade (99.8% purity) potassium iodide. SRM 2032 was issued with the technical assistance of J. R. Baldwin, R. W. Burke, A. L. Cummings, B. I. Diamondstone, and G. A. Sleater, and under the overall direction of I. L. Barnes.

The technical and support aspects concerning preparation, certification, and issuance of this SRM were

coordinated through the Office of Standard Reference Materials by R. W. Seward.

Washington, D.C. 20234 George A. Uriano, Chief

October 31, 1979 Office of Standard Reference Materials

(over)

164
Supplementary Information

Material Testing:

Material homogeneity was tested by measuring the absorbance of 1% aqueous solutions ofthe KI sampled from

the top, middle, and bottom of each bottle. These measurements, at 265, 267, and 270 nm, showed no evidence of

inhomogeneity. Tests for moisture content (Karl Fischer method) gave an average of 0.007%. This value was

sufficiently small that all certified data are based on weighed samples of the undried, as received, material.

Stability of the material to UV and visible light was tested by exposing the KI salt in a low-actinic glass bottle to radiation from a 3 kW xenon-arc lamp at a distance of 25 cm for four days at room temperature. The average absorbances at five wavelengths between 240 and 270 nm of aqueous solutions of the exposed material were 1.1% lower than those of solutions of the unexposed material. In view of the severity of this test, this change was

considered minor. Nonetheless, the 1.1% was included in the overall uncertainty of the certified values.

Certification Procedure:

The certified specific absorbances were measured in the NBS Center for Analytical Chemistry high-accuracy

spectrophotometer [1, 2], equipped with a deuterium lamp and UV averaging sphere [3, 4]. Thirteen aqueous

solutions of KI with concentrations ranging from 0.03 to 30 g L were prepared and measured against distilled water, using standard fused-silica cuvettes with pathlengths between 10.001 and 10.009 mm . The absorbance

measurements were performed at the temperature, t = 23.5 ± 0.5 °C. A 0.2 nm bandpass was used, and

wavelength settings were made with an accuracy of 0.05 nm. The measurements were made on at least three concentrations at each wavelength. These concentrations were chosen so that most absorbance readings fell between 0.1 and 1.0 to minimize stray light and bandwidth errors. The data were found to obey Beer's law.

Thus, the equation,

was used to calculate the specific absorbances, e, from the measured absorbances, A, and the known values of

concentration, c, and pathlength, E .

Limits to random error (two standard deviations) of these measurements (including the photometric

imprecision of the spectrophotometer, errors in the repositioning of cuvettes, concentration errors, pathlength

uncertainties, temperature errors, Beer's law uncertainties, and bandwidth errors) were determined to be ±

2.4%. The error due to the 0. 05 nm uncertainty qf the wavelength calibration of the spectrophotometer is ± 1 . 1 %.

The uncertainty of 5% stated on the face of this certificate represents the sum of these errors and the above

mentioned 1. 1% uncertainty due to instability of the KI. No corrections were applied for the effects of internal

reflections inside the sample and reference cuvettes, nor were the weights corrected to vacuum. These and all other sources of error were considered negligible.

The temperature coefficient at 260 nm was determined to be

For precision measurements, it is recommended that SRM 2032 be used in thermostated cuvettes at 23.5 °C, or

that a temperature correction according to Eq. (2) be applied.

b Issued by NBS as SRM 932, Quartz Cuvettes for Spectrophotometry.

e = A/cC (1)

—1 de -, Tt = 0.031 °C\ (2)

165
Instructions for Use

Storage and Preparation:

SRM 2032 should be stored in the original, low-actinic glass bottle and the cardboard container in which it was

issued to protect it from unnecessary exposure to light and humidity. When so stored, the expected stability of

this material is at least three years. Thus, until additional stability data are obtained, this material should be used

within three years of the date of purchase.

All solutions prepared from SRM 2032 should be made in borosilicate glass containers using distilled water and

transfer pipettes (Pasteur type) of the same glass and fitted with rubber bulbs

0

. Use clean spectrophotometer

cuvettes, free of scratches, made of non-fluorescent fused silica, and fitted with ground-glass or Teflon stoppers

to minimize evaporation; or preferably use NBS SRM 932. Mark all cuvettes to assure the same orientation in the spectrophotometer, and place them into their respective holders. Using transfer pipettes of the type

mentioned, rinse each cuvette several times with distilled water. Prepare a solution of KI in distilled water (e.g., 1%), fill the sample cuvette with the KI solution and the reference cuvette with distilled water. Measure the absorbance, leaving the cuvettes in their holders, empty them (using the pipettes), and repeat the rinsing and

filling operations until constant absorbance readings are obtained. Fresh solutions should be made before every

test.

Measurements:

A 1% KI solution (c = 10 g L ') with a 1 cm pathlength exhibits a sharp cutoff in transmittance near 260 nm; i.e.,

it transmits more than 90% above 273 nm, but less than 0.01% below 258 nm. Therefore, with the monochromator set for a wavelength below 260 nm, any appreciable amount of light detected is heterochromatic stray light, which consists of wavelengths above the cutof f. The amount of stray light in the spectrophotometer at wavelength A. may be determined from the equations:

r(X)= IWlU&L ( 3)

1 + x(X)

jm - T(A)

(4)

where:

x(\) is the stray light ratio

,

T'(X) is the apparent transmittance i

T(\) is the true transmittance.

The stray light ratio, x(\), is the proportion of heterochromatic stray radiant energy in the spectrophotometer

for the wavelength setting k. Equation (4) forms the theoretical basis for the determination of the stray light ratio by comparing apparent transmittance to true transmittance. For SRM 2032, the true transmittance, T(\), of KI

solutions may be calculated as: T(X)=10-

f(X)CC

where e(X) is the certified specific absorbance given on the face of this certificate.

°Soft glass containers and pipettes contain residual amounts ofUV absorbing material, but can be used after proper cleaning. Several rinses,

first with isopropyl alcohol and then with distilled water, are generally adequate.

166
The apparent transmittances of KI solutions depend not only on the stray light ratio of the spectrophotometer,

but also on the wavelength accuracy and the spectral bandwidth, which can significantly affect the results obtained because of the steep slope of the absorbance cutoff of KI. A low-pressure mercury discharge lamp is suggested for verifying the wavelength scale, and a bandwidth as narrow as compatible with adequate signal-tonoise ratios should be used. Many instruments do not permit the direct measurement of transmittances below certain limits, e.g., 1% or

0. 1.. For such instruments, the use of SRM 2032 will only measure stray light ratios above these limits. To

measure stray light ratios below these limits, the reference beam of the spectrophotometer must be attenuated to extend the transmittance scale into the low-transmittance region.

References

1. R. Mavrodineanu, J. Res. NBS 76A, 405-425 (1972).

2. J.F. Barkley, F. C. Ruegg, and R. Mavrodineanu, 29th Pittsburgh Conf., Abstract 452, Cleveland, Ohio,

(1978).

3. K. D. Mielenz, R. Mavrodineanu, and E. D. Cehelnik, J. Res. NBS 78A, 631-635 (1974).

4. K. D. Mielenz, R. Mavrodineanu, and E. D. Cehelnik, Appl. Optics 14, 1940-1947 (1975).

167
NBS-114A (rev. 2-BO

U.S. DEPT. OF COMM. 1. PUBLICATION OR 2. Performing Organ. Report No. 3. Publication Date BIBLIOGRAPHIC DATA

REPORT NO.

SHEET (See instructions) NBS SP 260-71 November 1981

4. TITLE AND SUBTITLE

Standard Reference Materials:

Summary of the Clinical Laboratory Standards Issued by the National Bureau of

Standards

5. AUTHOR(S)

R.W. Seward and R. Mavrodineanu

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions) 7. Contract/Grant No.

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE 8. Type of Report & Period Covered

WASHINGTON, D.C. 20234

Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State, ZIP)

Same as above

10. SUPPLEMENTARY NOTES

Library of Congress Catalog Card Number: 81-600149

I Document describes a computer program; SF-185, FlPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bib/iography or literature survey, mention it here)

This publication is a summary of the Clinical Laboratory Standards issued by

NBS as Standard Reference Materials (SRM's). The material, composition,

certification, use, and remarks concerning each of the SRM's described

are presented in tabular form. Copies of the certificates for these SRM's

are contained in the appendix for more detailed information.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Chemical composition; clinical materials; Standard Reference Materials

13. AVAILABILITY

[X"] Unlimited

|

| For Official Distribution. Do Not Release to NTIS

[XI Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402.

\~\ Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

176

15. Price

<|U.S. GOVERNMENT PRINTING OFFICE:

USCOMM-DC 6043-P80

I 981-360-997/1864






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students, and consumers of the latest advances in science and

technology, with primary emphasis on work at NBS. The magazine

highlights and reviews such issues as energy research, fire protection, building technology, metric conversion, pollution abatement,

health and safety, and consumer product performance. In addition, it reports the results of Bureau programs in measurement

standards and techniques, properties of matter and materials,

engineering standards and services, instrumentation, and

automatic data processing. Annual subscription: domestic $11;

foreign $13.75.

NONPERIODICALS

Monographs—Major contributions to the technical literature on

various subjects related to the Bureau's scientific and technical activities. Handbooks—Recommended codes of engineering and industrial practice (including safety codes) developed in cooperation with in- terested industries, professional organizations, and regulatory

bodies.

Special Publications—Include proceedings of conferences sponsored by NBS, NBS annual reports, and other special publications

appropriate to this grouping such as wall charts, pocket cards, and

bibliographies.

Applied Mathematics Series—Mathematical tables, manuals, and

studies of special interest to physicists, engineers, chemists,

biologists, mathematicians, computer programmers, and others engaged in scientific and technical work.

National Standard Reference Data Series—Provides quantitative data on the physical and chemical properties of materials, compiled from the world's literature and critically evaluated.

Developed under a worldwide program coordinated by NBS under

the authority of the National Standard Data Act (Public Law

90-396).

NOTE: The principal publication outlet for the foregoing data is the Journal of Physical and Chemical Reference Data (JPCRD)

published quarterly for NBS by the American Chemical Society

(ACS) and the American Institute of Physics (AIP). Subscriptions,

reprints, and supplements available from ACS, 1 155 Sixteenth St., NW, Washington, DC 20056.

Building Science Series—Disseminates technical information

developed at the Bureau on building materials, components,

systems, and whole structures. The series presents research results,

test methods, and performance criteria related to the structural and

environmental functions and the durability and safety characteristics of building elements and systems.

Technical Notes—Studies or reports which are complete in themselves but restrictive in their treatment of a subject. Analogous to monographs but not so comprehensive in scope or definitive in treatment of the subject area. Often serve as a vehicle for final reports of work performed at NBS under the sponsorship of other government agencies.

Voluntary Product Standards—Developed under procedures

published by the Department of Commerce in Part 10, Title 15, of

the Code of Federal Regulations. The standards establish nationally recognized requirements for products, and provide all concerned interests with a basis for common understanding of the

characteristics of the products. NBS administers this program as a supplement to the activities of the private sector standardizing

organizations.

Consumer Information Series—Practical information, based on NBS research and experience, covering areas of interest to the con- sumer. Easily understandable language and illustrations provide

useful background knowledge for shopping in today's technological marketplace.

Order the above NBS publications from: Superintendent of Documents, Government Printing Office, Washington. DC 20402. Order the following NBS publications—FIPS and NBSlR's—from

the National Technical Information Services, Springfield, VA 22161.

Federal Information Processing Standards Publications (FIPS

PUB)—Publications in this series collectively constitute the Federal Information Processing Standards Register. The Register

serves as the official source of information in the Federal Government regarding standards issued by NBS pursuant to the Federal Property and Administrative Services Act of 1949 as amended,

Public Law 89-306 (79 Stat. 1127), and as implemented by Executive Order 11717(38 FR 12315, dated May 11, 1973) and Part 6 of Title 15 CFR (Code of Federal Regulations).

NBS Interagency Reports (NBSIR)—A special series of interim or

final reports on work performed by NBS for outside sponsors

(both government and non-government). In general, initial dis- tribution is handled by the sponsor; public distribution is by the National Technical Information Services, Springfield, VA 22161,

in paper copy or microfiche form.
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