ED STATES \RTMENT OF 1MERCE

LIGATION NBS SPECIAL PUBLICATION 260-32

oo

157

1 U.S. ARTMENT

OF

OMMERCE

National Bureau

of Standards

Standard Reference Materials:

STANDARD QUARTZ CUVETTES

FOR HIGH ACCURACY SPECTROPHOTOMETRY
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards 1 was established by an act of Congress 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 consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology,

the Institute for Computer Sciences and Technology, and the Office for Information Programs. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United

States of a complete and consistent system of physical measurement; coordinates that system

with measurement systems of other nations; and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of a Center for Radiation Research, an Office of Measurement Services and the following divisions: Applied Mathematics — Electricity — Mechanics — Heat — Optical Physics — Nuclear

Sciences 2 — Applied Radiation 2 — Quantum Electronics 3 — Electromagnetics 3 — Time

and Frequency 3 — Laboratory Astrophysics 3 — Cryogenics 3. THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to improved methods of measurement, standards, and data on the properties of well-characterized materials needed by industry, commerce, educational institutions, and Government; provides

advisory and research services to other Government agencies; and develops, produces, and

distributes standard reference materials. The Institute consists of the Office of Standard Reference Materials and the following divisions: Analytical Chemistry — Polymers — Metallurgy — Inorganic Materials — Reactor

Radiation — Physical Chemistry. THE INSTITUTE FOR APPLIED TECHNOLOGY provides technical services to promote

the use of available technology and to facilitate technological innovation in industry and

Government; cooperates with public and private organizations leading to the development of

technological standards (including mandatory safety standards), codes and methods of test; and provides technical advice and services to Government agencies upon request. The Institute consists of a Center for Building Technology and the following divisions and offices: Engineering and Product Standards — Weights and Measures — Invention and Innovation — Product Evaluation Technology — Electronic Technology — Technical Analysis — Measurement Engineering — Structures, Materials, and Life Safety* — Building Environment* — Technical Evaluation and Application* — Fire Technology. THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts research and provides technical services designed to aid Government agencies in improving cost effec- tiveness in the conduct of their programs through the selection, acquisition, and effective utilization of automatic data processing equipment; and serves as the principal focus within

the executive branch for the development of Federal standards for automatic data processing equipment, techniques, and computer languages. The Center consists of the following offices and divisions: Information Processing Standards — Computer Information — Computer Services —

Systems Development — Information Processing Technology. THE OFFICE FOR INFORMATION PROGRAMS promotes optimum dissemination and

accessibility of scientific information generated within NBS and other agencies of the Federal Government; promotes the development of the National Standard Reference Data System and

a system of information analysis centers dealing with the broader aspects of the National Measurement System; provides appropriate services to ensure that the NBS staff has optimum

accessibility to the scientific information of the world. The Office consists of the following

organizational units: Office of Standard Reference Data — Office of Technical Information and Publications —

Library — Office of International Relations.

1 Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted; mailing address Washington, D.C. 20234.

a Part of the Center for Radiation Research.

3 Located at Boulder, Colorado 80302.

* Part of the Center for Building Technology.
lational Bursal! ,,

!- APR 2 9 1974 Standard Reference Materials:

Standard Quartz Cuvettes

For High Accuracy Spectrophotometry

R. Mavrodineanu

Analytical Chemistry Division

Institute for Materials Research

J. W. Lazar

Optical Physics Division

Institute for Basic Standards

National Bureau of Standards Washington, D.C. 20234

U.S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Director

Issued December 1973

and
Library of Congress Catalog Number: 73-600200

National Bureau of Standards Special Publication 260-32

Nat. Bur. Stand. (U.S.), Spec. Publ. 260-32, 26 pages (Dec. 1973) CODEN: XNBSAV

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1973

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 (Order by SD Catalog No. C13.10.-260-32). Price 55 cents.
PREFACE

Standard Reference Materials (SRM's) as defined by the

National Bureau of Standards are "well - characteri zed materials, produced in quantity, that calibrate a measurement

system to assure compatibility of measurement in 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. In many industries

traceability of their quality control process 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 Publication - 260 Series is reserved for this

purpose

This 260 Series is dedicated to the dissemination of

information on all phases of the preparation, measurement,

and certification 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. It is also

hoped that these papers will 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

J. Paul Cali, Chief

Office of Standard Reference Materials

iii
OTHER NBS PUBLICATIONS IN THIS SERIES

NBS Spec. Publ. 260, Catalog of Standard Refer- ence Materials, July 1970. 75 cents.* (Supersedes NBS Misc. Publ. 260, January 1968 and NBS Misc. Publ. 241, March 1962.) NBS Misc. Publ. 260-1, Standard Reference

Materials: Preparation of NBS White Cast

Iron Spectrochemical Standards, June 1964. 30 cents.* NBS Misc. Publ. 260-2, Standard Reference Materials: Preparation of NBS Copper-Base

Spectrochemical Standards, October 1964. 35 cents.* NBS Misc. Publ. 260-3, Standard Reference Materials: Metallographic Characterization of an NBS Spectrometric Low-Alloy Steel Standard, October 1964. 20 cents.* (Out of print). NBS Misc. Publ. 260-4, Standard Reference

Materials: Sources of Information on Standard Reference Materials, February 1965. 20 cents.* (Out of print). NBS Misc. Publ. 260-5, Standard Reference

Materials: Accuracy of Solution X-Ray Spectrometric Analysis of Copper-Base Alloys, March 1965. 25 cents.* (Out of print). NBS Misc. Publ. 260-6, Standard Reference

Materials: Methods for the Chemical Analysis of White Cast Iron Standards, July 1965. 45 cents.* NBS Misc. Publ. 260-7, Standard Reference

Materials: Methods for the Chemical Analysis of NBS Copper-Base Spectrochemical Standards, October 1965. 60 cents.* NBS Misc. Publ. 260-8, Standard Reference

Materials: Analysis of Uranium Concentrates

at the National Bureau of Standards, December 1965. 60 cents.* (Out of print). NBS Misc. Publ. 260-9, 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, November

1965. 15 cents.* NBS Misc. Publ. 260-10, Standard Reference

Materials: Homogeneity Characterization on NBS Spectrometric Standards II: Cartridge

Brass and Low-Alloy Steel, December 1965. 30 cents.* NBS Misc. Publ. 260-11, Standard Reference

Materials: Viscosity of a Standard Lead-Silica

Glass, November 1966. 25 cents.*

NBS Misc. Publ. 260-12, Standard Reference

Materials: Homogeneity Characterization of NBS Spectrometric Standards III: White Cast Iron and Stainless Steel Powder Compact,

September 1966. 20 cents.* NBS Misc. Publ. 260-13, Standard Reference

Materials: Mossbauer Spectroscopy Standard

for the Chemical Shift of Iron Compounds,

July 1967. 40 cents.* NBS Misc. Publ. 260-14, Standard Reference

Materials: Determination of Oxygen in Fer- rous Materials - SRM 1090, 1091, and 1092, September 1966. 30 cents.* NBS Misc. Publ. 260-15, Standard Reference

Materials: Recommended Method of Use of Standard Light-Sensitive Paper for Calibrat- ing Carbon Arcs Used in Testing Textiles for Colorfastness to Light, June 1967. 20 cents.* NBS Spec. Publ. 260-16, Standard Reference

Materials: Homogeneity Characterization of NBS Spectrometric Standards IV: Preparation and Microprobe Characterization of W-20% Mo Alloy Fabricated by Powder

Metallurgical Methods, January 1969. 35 cents.* NBS Spec. Publ. 260-17, Standard Reference

Materials: Boric Acid; Isotopic and Assay Standard Reference Materials, February

1970. 65 cents.* NBS Spec. Publ. 260-18, Standard Reference

Materials: Calibration of NBS Secondary

Standard Magnetic Tape (Computer Amplitude Reference) Using the Reference Tape

Amplitude Measurement "Process A", No- vember 1969. 50 cents.* NBS Spec. Publ. 260-19, Standard Reference

Materials: Analysis of Interlaboratory Meas- urements on the Vapor Pressure of Gold

(Certification of Standard Reference Material 745), January 1970. 30 cents.* NBS Spec. Publ. 260-20, Standard Reference

Materials: Preparation and Analysis of Trace Element Glass Standards. (In preparation) NBS Spec. Publ. 260-21, Standard Reference

Materials: Analysis of Interlaboratory Meas- urements on the Vapor Pressures of Cadmi- um and Silver, January 1971. 35 cents.* NBS Spec. Publ. 260-22, Standard Reference

Materials: Homogeneity Characterization of

Fe-3Si Alloy, February 1971. 35 cents.* iv
NBS Spec. Publ. 260-23, Standard Reference NBS Spec. Publ. 260-34, Standard Reference

Materials: Viscosity of a Standard Borosili- Materials: Thermoelectric Voltage, April

cate Glass, December 1970. 25 cents.* 1972. 40 cents.* NBS Spec. Publ. 260-24, Standard Reference NBS Spec. Publ. 260-35, Standard Reference

Materials: Comparison of Redox Standards, Materials: Thermal Conductivity of Austen- January 1972. $1.* itic Stainless Steel, SRM 735 from 5 to NBS Spec. Publ. 260-25, Standard Reference 280 K, April 1972. 35 cents.*

Materials: A Standard Reference Material NBS Spec. Publ. 260-36, Standard Reference

Containing Nominally Four Percent Austen- Materials: A Referee Method for the Deterite, February 1971. 30 cents.* mination of Calcium in Serum. SRM 915, NBS Spec. Publ. 260-26, Standard Reference May 1972. $1.25.*

Materials: National Bureau of Standards— NBS Spec. Publ. 260-37, Standard Reference

U.S. Steel Corporation Joint Program for De- Materials: Methods of Analysis of NBS Clay

termining Oxygen and Nitrogen in Steel, Feb- Standards, June 1972. 75 cents.* ruary 1971. 50 cents.* NBS Spec. Publ. 260-38, Standard Reference NBS Spec. Publ. 260-27, Standard Reference Materials: Preparation and Calibration of

Materials: Uranium Isotopic Standard Refer- Standards of Spectral Specular Reflectance, ence Materials, April 1971. $1.25.* May 1972. 60 cents.* NBS Spec. Publ. 260-28, Standard Reference NBS Spec. Publ. 260-39, Standard Reference

Materials: Preparation and Evaluation of Materials: The Eddy Current Decay Method

SRM's 481 and 482 Gold-Silver and Gold- for Resistivity Characterization of High-PurCopper Alloys for Microanalysis, August ity Metals, May 1972. 55 cents.* 1971. $1.* NBS Spec. Publ. 260-40, Standard Reference NBS Spec. Publ. 260-29, Standard Reference Materials: Selection of Thermal Analysis

Materials: Calibration of NBS Secondary Temperature Standards Through a CooperaStandard Magnetic Tape (Computer Ampli- tive Study (SRM 758, 759, 760), August

tude Reference) Using the Reference Tape 1972. 65 cents.* Amplitude Measurement "Process A-Model NBS Spec. Publ. 260-41, Standard Reference

2", June 1971. 60 cents.* Materials: Use of Standard Light-Sensitive NBS Spec. Publ. 260-30, Standard Reference Paper for Calibrating Carbon Arcs used in Materials: Standard Samples Issued in the Testing Textiles for Colorfastness to Light, USSR (A Translation from the Russian), August 1972. 30 cents.* June 1971. $1.* NBS Spec. Publ. 260-42, Standard Reference NBS Spec. Publ. 260-31, Standard Reference Materials: The Characterization of Linear

Materials: Thermal Conductivity of Electro- Polyethylene, SRM 1475, September 1972.

lytic Iron SRM 734 from 4 to 300 K, Novem- 45 cents.* ber 1971. 35 cents.* NBS Spec. Publ. 260-43, Standard Reference NBS Spec. Publ. 260-32, Standard Reference Materials: Preparation and Homogeneity

Materials: The Cooperative Study of Temper- Characterization of an Austenitic Ironature Scale Standards for DTA by ICTA and Chromium-Nickel Alloy, November 1972. NBS. (In preparation) 45 cents.* NBS Spec. Publ. 260-33, Standard Refererence NBS Spec. Publ. 260-44, Standard Reference

Materials: Comparison of Original and Sup- Materials: Preparation and Use of Supercon- plemental SRM 705, Narrow Molecular ductive Fixed Point Devices, SRM 767, De- Weight Distribution Polystyrene, H. L. Wag- cember 1972. 75 cents.*

ner, May 1972. 35 cents.* NBS Spec. Publ. 260-45, Standard Reference

Materials: Powdered Lead-Based Paint, SRM

1579. (In preparation)

*Send order with remittance to: Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. Remittance from foreign countries should include an additional onefourth of the purchase price for postage. V
CONTENTS

PAGE

I. INTRODUCTION 1

II. EXPERIMENTAL 2

III. APPLICATIONS 6

IV. REFERENCES 17

LIST OF TABLES

Table No. PAGE

1. Radiation pathlength expressed in mm and

determined on 17 quartz cuvettes made at NBS. ... 5

2. Radiation pathlength expressed in mm and

determined on 10 quartz cuvettes made by a commercial manufacturer 7

LIST OF FIGURES

Figure No. PAGE

1. Fused silica material and parts used for

constructing the cuvettes for high- accuracy

spectrophotometry 11 2a. Standard instrument for measuring the thickness

of plates and length of quartz segments 12

2b. Close-up of figure 2a 13

3. General shape and nominal dimensions (mm) of

NBS quartz standard cuvette for spectrophotometry 14 4a. General view of the standard instrument used to measure the radiation pathlength of cuvettes. ... 15 4b. Close-up of figure 4a 16

vi
STANDARD REFERENCE MATERIALS:

STANDARD QUARTZ CUVETTES FOR HIGH ACCURACY SPECTROPHOTOMETRY

R. Mavrodineanu

Analytical Chemistry Division

Institute for Materials Research

National Bureau of Standards

Washington, D. C. 20234

and

J. W. Lazar

Optical Physics Division

Institute for Basic Standards

National Bureau of Standards

Washington, D. C. 20234

Accurate knowledge of lightpath and parallelism of

cuvettes used in spectrophotometry is one of the indispensable parameters which must be determined when

accurate transmittance measurements of liquid materials

is considered. A description is given of the design

and techniques developed at NBS for the production of

quartz cuvettes having a nominal radiation pathlength

of 10 mm _+ 0.03 mm. For each cuvette the pathlength and

parallelism are certified with an uncertainty of +_ 0.0005

mm. The method and instrumentation used to determine

these parameters is also described in the paper.

Key words: Cuvette, spectrophotometry; lightpath;

pathlength; quartz, cuvette; radiation pathlength.

I. INTRODUCTION

True transmittance values can be obtained only when

using accurate measuring techniques and by taking into

consideration all factors which can affect and distort

the data [1]. Since transmittance is the ratio. of two radiation flux intensities, it is necessary that the

photometric scale of the spectrophotometer used be

accurate. Other important conditions which must be

satisfied are: wavelength accuracy, use of adequate

spectral bandpass, use of collimated radiation, freedom

from reflections (interreflection) , fluorescence, polarization,

light scatter, optical interferences, particulate matter.

Surface conditions and the temperature at which the

measurements are performed must be defined, and the material

subjected to measurements must be homogeneous (freedom

of strain) and stable.

When liquid samples are measured the pathlength of

the radiation passing through the solution must be

accurately known. This last condition is particularly

important, not only when accurate transmittance measurements are contemplated, but also when the molar absorptivity

of a chemical species is sought. In these cases, an un- certainty of 0.1 mm in a nominal radiation pathlength of

10 mm for instance, will result in an error of 1 percent

in the absorbance measurements, and, similarly, an un- certainty of 0.01 mm will result in an error of 0.1 percent

absorbance. The object of the work discussed in this

paper is to describe the procedures developed and used

in the construction of quartz cuvettes having a nominal

radiation pathlength of 10 mm +_ 0.03 mm, parallelism

between the two transparent plates within 0.002 mm, plate flatness of 2 to 3 fringes (mercury green line)

and parallelism of these plates within 0.002 mm over

the whole length of the plates.

1
Additional conditions to be met were free from

fluorescence and strain, and the use of fused silica of

optical grade.

The fulfillment of these specifications would

practically eliminate the radiation pathlength error when

absorbance measurements are performed at an uncertainty

level of 0.1 percent. Such an accuracy seems to be

at the limit obtainable by the present state of the art when measurements of absorbance are performed on liquid

samples, and include the errors of sample preparation and

handling, as well as the instrument uncertainty.

II. EXPERIMENTAL

Several designs were contemplated for constructing

quartz cuvettes which would satisfy the rather tight

specifications mentioned above. The technique illustrated

in figure 1 was finally selected, and was developed in

association with E. P. Muth of NBS Optical Shop, who also

made all the parts required for the cuvettes discussed in

this work. The final assembly was performed by E. I. Klein

from NBS Glassblowing Shop. A rectangular- shaped fused-silica structure 48.0 mm

high, 13.5 mm wide and 300 mm long was used to make the body

of the cuvettes. Segments approximately 13 mm long were

cut from this material and ground and polished, using conventional optical shop techniques, to produce a rectangular

segment 10 mm +_ 0.03 mm long. The rectangular edges of

each segment were finished to a flatness of 1 to 2 fringes

(mercury green line) , and at one end a small orifice was- provided to permit air expansion during the assembly

operation.

The length of every segment was checked for accuracy

with a standard measuring instrument, illustrated in

2
figure 2a and b, capable of determining this length with an accuracy of +_ 0.5 ym. Two plates made of non-fluorescent fused silica 51 mm

long, 16 mm wide and 2 mm thick were ground and polished

in a similar manner to a width of 12.5 mm, a thickness

of 1.1 mm with a parallelism of 0.002 mm and a flatness

of about 2 fringes (mercury green line) as shown in figure 1. These plates were checked for thickness with the instrument illustrated in figure 2a, b and were attached to the

rectangular body by careful welding with city gas-oxygen

torch using a needle shape flame.

The top of the assembled unit was then cut to produce

a cuvette 43 mm high, and a rectangular fused silica block

of 6, mm was attached to the open end of the cuvette by

fusion. This block was provided with a standard tapered

opening with a diameter of 10 mm at the top. A standardtaper Teflon stopper was used to provide tight closure of

the cuvette (fig. 1) . The cuvette was finished by

grinding the two side walls and bevelling the edges. Its nominal dimensions are given in figure 3. The unit was stress-released by proper annealing.

The cuvette was then measured to determine the radiation

pathlength and the parallelism of the unit. For this purpose

the instrument illustrated in figure 4a and b was used, all

measurements being performed at a temperature of 20° +_ 0 o 05 °C. The measurements were made as described below.

The cuvettes were lightly clamped in a fixture which

was bolted to the table of a Moore No. 3 Measuring Machine*

The identification of commercial instruments and products

is given only to permit reproduction of the work described in

this paper. In no instances does such identification imply

recommendation or endorsement by the National Bureau of

Standards, nor does it imply that the particular equipment or product is necessarily the best available for the purpose.

3
and were adjusted until the two plates which define the

radiation path length were vertical within the limits of

their parallelism. An electronic lever type gage, with

a resolution of 0.125 ym was mounted on the spindle. To reach the bottom of the cuvette, a longer lever was fabricated and mounted on the gage. Use of the longer

lever required that a correction factor be applied to all

measurements which decreased the resolution of the gaging

system to 0.312 ym. As shown in Figure 4b, a combination of gage blocks

and end plates were wrung together so that the distance

between the inside faces of the end plates was 10.0000 + 0.0001 mm. The gage blocks were then positioned beneath

the center of the spindle and the gage lever was offset

from the center of rotation of the spindle so that when

the spindle was rotated 180° and the lever contacted

each end plate the meter readout of the gaging system was

at its null (zero) position.

The machine table was then moved to position the

cuvette beneath the spindle. The spindle was lowered

until the gage lever was at its first measuring position

inside the cuvette. The table was moved until the lever

contacted the face of the cuvette and the meter was at its zero position. The spindle was rotated 180° until the

gage lever contacted the opposite side of the cuvette. The

meter reading multiplied by the correction factor plus the

nominal 10 mm path length gave the true pathlength at that point. Measurements were made approximately every 4 mm

by lowering the spindle.

Seventeen quartz cuvettes were made and measured at NBS according to the procedures described in this paper,

and the values found are presented in table 1.

4
3 +-> o" c:

r-{ rep. C </> o c

<D 4-> c

•H D

+-> >

C 3

0) U

e +-> o

x: x>

•H 6

O CTi O Cn Cn Cn Cn O O Ol £71 Ol cncocncncocnoocn CncncncnCncnOOCn

o cn o cn CTi Cn Cn O O Cn ocnocncncncncncncocncn OOlOOlOlOClClOlCtCTiOl

Ol H \D Ol ^ r- cn o o oo

co cn o o cn

cn cn o o cn ocnocncncncncncncncncncncnoo

fll N <J N M Cl

r-. m oo o o ocnocncncncncncnoocncn OOlOOlOlClOlOlO^CTlCIlOiClOlOOOl

OOlOQlClQQCJlOlOlCltTl

\o cn cn o cn o cn cn cn cn o cn o cn

cn oo cn cn

cn o o cn

vo cn o o fco cn o o cn cncncncn cncncncncnoocn

o cn o cn cn cn cn cn cn

r~ (Ni rcn cn cn o or— «3- to ho cn cnocncncncncncncocncn

o cn o cn cn cn cn cn cn cn

cn o o \o

cn o o cn cn cn o o cn cnocncncncncncncncncncn

o co rH cn cn o cn o cn cn cn cn cn cncn o o

cn o o cn cnocncncncncncncncncncncnoocn

o cn cn cn cn cn cn cn cn cn cn o

r-l TJ- (N) r-, cn oo r~~ in to cn cn cn o cn cn cn cn cn cn cn cn o cn cn cn cn cn cn cn

co cn cn cn cn

cn cn cn cn cn

cn cn o cn cn cn cn cn cn cn cn

to o o

cn oo o

cn cn cn cn

cn r-~ cn o vo cncnocncncn cncncncocncn cncnocn-cncncncncncncncn cncnocncncn cncncncncncncncncn

rHLOK1^3-CVJi-ll-0^3-C-10CnrHi-(OOiHt~- cnt^OLnt-^coi--M-t-^rHcooocnt^.cncn cncnocncncncncncncocncncocncncn

cncnocncncn cncncncncncncncncncn cncnocn cncn cncncncncncncncncncn

vo o vd to cncncncncncn cncncn

co co cn t co cn vo cn cn co cn cn cn cn cncncncncncncncncncncncncncncncncn

cncncncncncn cncncncn cn cn cn cn cn N Ol ID s s

01

cn cn

t~- o t^> o oo oc

-» Ln VD (NI co t-^ cn cn cn oo cn cn

cn cn cn cn cn cncncncncncncncncn cn

cn cn

c-i o o a

:-~ o o

vo co n- \D t-T> to cncnocncncn cncncncocncncn

cn cn cn cn

cn cn cn cn cn cn cn cn cnocncncn cncncncncncncncncncncn

cn cn o cn cn cn cn cn cn cn cn cn

iH t-~ vo \o r»

cn cn o cn cn cn

co co vo cncocncncncncncncn cncncncncncncncncncncncncn cncnocncncn cncncn cn

vo t-~ oo cn o

cn cn cn cn cn
From these data it can be concluded that only three

of the 17 cuvettes, or less than 18 percent of the NBS

cuvettes, were below the specifications established for

acceptance

.

The same measurements were performed on 10 quartz

cuvettes of commercial origin. The results assembled in

table 2 show that only 4 of the 10 cuvettes were acceptable

by the standards established in this paper, which indicate

a rejection of 60 percent. It must be noted, however, that

9 of 10 cuvettes were within the specifications of the

manufacturer which indicate a tolerance of nominal lightpath of 10 mm + 0.01 mm.

III. APPLICATIONS

As a result of these measurements, it was decided to ^produce at NBS a number of quartz cuvettes, identical

to those described in this work, and to certify them

for radiation pathlength and parallelism. These cuvettes

would then constitute a Standard Reference Material (SRM)

in spectrophotometry, and be made available to the public

as SRM 932. Each cuvette will have a certificate of

calibration of which a reproduction is given here.

6
6oP rH o CTt oo to ^1- VO to CM

CM r-~ rH (Nl CM o vo o to \o o (XI i—

rH o rH rH T—

o o

rH pq o o O o O O o o o o

PJ o o o o o O O o o o o o rH rH rH

^JJ •H oo rH tO CTt to to CM CM LO

LO rH r>- tO tO CM CTt rH oo oo o CM rH o O o o

Ph CTt o O O o O O O o o o g . o o O o o O o o o o 0 CD O 0 rH rH rH rH rH rH rH 0

+-> ^ fn P o P P MH P pi

CD CD 0 CM OO rH CM oo to 00 to CM oS bO > VO LO to o r- co CM oo P

Pi 3 rH O rH rH rH o rH o Ph

•H O 00 o O o o o O o o o o 0

CD o

"fn MH o O ' o o o O o o o o o P fH CCS O rH rH rH rH aJ

fH O 4-1 OS MH (/) g fH 3 fn o LO 00 CN1 oo oo oo 00 o

vO \o CM CO vO o o MH"

PL, 0 P CM rH rH o rH o rH o rH o T3 O r>- o o O o o o o o o o

i—l 0 oS ,0 0

fn • g o o o o o o o CO- o o

Pi ct3 U g i—

rH rH Mh O o 0 O

LO fn fn u

13 P O 0 MH 00 LO crt en to CM LO to 0

J) fj N rH vO LO to LO CTt vo vO vO rH Ph

PI 0 g eg rH o rH O rH o o in •H g P V) g vo o O o o o o O o o o g 0 oS 4-J 10

fn fn PI CM o o o o o o o o o o 0 3 •> 0 P 10 10 g «N g 0 rt 0 0 O

t3 0 )-) fn rH oo CTt O0 CM VO o rH CM to rH 6 cci pj o LO to to o vO vO CTt T3 i—

00 d eg o o o o 0

Pi 0 Ph oS O LO o o o o o o O o o o 0 »H p

E-h 4-> g +J o o o o o o o o o o g Pi rH rH rH rH rH g 0 X co 0 • fH U O 0

p| fn aJ •H PL, CM cm vO ^H^ to VO co LO CN1 o H 0 Ph ,d rH LO LO to LO CTi to 00 vO 00 x o o o o o 0

"O |3 Pi o o o o o o o o o o 0 P a3 P -H 10

l/l o ^ rt ;s o o o o O o o o o o 0

V) d P rH rH rH rH rH rH rH rH p 0 MH co bo +J

fH Pi 0 PI Pi 0

PL, PI X O 'H oo LO CTt CM to rH o f-. OO > X cti +-> •H T3 vO vO «H^ CTt to t>- vO 00 0 6 P Pi CM rH o o o o o CJ m •H 0 to o O O o o O O o o o

r-H O CO 0

+-> as O o o O o o o O o o o tn 0J>H (/) Pi £ rH rH rH rH 0

Pi U 0 o3 ^! 0 fn O Mh P

i—( 0 03 O Ph CN1 vO CTt LO CTt o CM o o o oo LO to \o CTt LO vO CM o 5h P s pi p o o o o o

n) o H o CNJ o o o o O O o o o o Mh

P, U 03 •H g

pj P o o o o o O o O o o o t)

Pi 03 fn OS fn rH rH i—

0 O 0 O <+-( pi •H >-, P P i Pi Mh g 00 CNJ vo CM rH CM vO oo o3

o3 -H •H g o vO CM «H- r>- LO vO CTt +j • H 0 4-J Pm o o rH o o i-i h3 T) 0 Pi vO o o o o o o o O o o o o

oS a3 X 0 E-H £ P T3 P o o o o o o o o o o Cfl rH 03 rH rH rH rH rH rH 0

pi rH

(X) 0

4-> > 0 P

rH 0 O * * * * 0

hO > CM to LO vO 00 CTt o ,C| 03 E-h E-h U K 7
National Bureau of Standards

CERTIFICATE

STANDARD REFERENCE MATERIAL 932

QUARTZ CUVETTE FOR SPECTROPHOTOMETRY

R. Mavrodineanu and J. W. Lazar

This Standard Reference Material is intended as a reference source when production of accurate spectrophotometry data on liquid samples is considered. It consists of an all-quartz rectangular cuvette designed

to fit the holder of conventional spectrophotometers. It is provided with two optically transparent and parallel

windows defining a nominal radiation pathlength of 10 mm

+_ .03 mm. The inner surfaces of the windows are parallel

within .002 mm. The pathlength and parallelism are certified with an uncertainty of +_ 0.0005 mm as determined

by measurements at positions equally spaced 2 mm from the

bottom to within 6 mm of the stopper top. These measurements are made at 20 °C, and the distance between each

position is about 4 mm. Position of

Measurement

Radiation

Pathlength, mm

Bottom

Top

98

7

6

543

2

1

9.999

9.999

10.000

9.999

10.000

9.999

9.998

9.998

9.998

9.997

9.997

8
The general shape and nominal dimensions of the

cuvette are illustrated in the figure.*

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 0. 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.

J. Paul Cali, Chief

Office of Standard Reference Materials

Washington, D. C. 20234

March 1, 1973

*Note: This figure is identical with figure 3 of this paper.

9
The cuvette was designed and produced at the National

Bureau of Standards by special techniques and from non- fluorescent optical-quality fused silica. The transparent

windows are attached to the body of the cuvette by direct

fusion, and the unit was strain-released by proper

annealing. The overall flatness of the transparent windows

is within two fringes (546-nm Hg line) , and their parallelism

is within two micrometers. The radiation pathlength measurements were performed before and after the assembly of the

cuvette using electronic feeler- gage type instruments

capable t of a resolution of 5 parts in 10^. SRM 932 is a result of the combined efforts of the Analytical Chemistry

Division, Institute for Materials Research, the Optical

Physics Division of the Institute for Basic Standards,

and the Instrument Shops Division.

E. P. Muth and E. I. Klein designed and assembled the

cuvette respectively. The radiation pathlength measurements were performed by E . G. Erber.

SRM 932 was developed to meet the needs expressed by

the Standards Committee of the American Association of

Clinical Chemists under the chairmanship of George N. Bowers,

Jr., M. D. , Hartford Hospital, Hartford, Connecticut.

This work was initiated and performed with the approval

and encouragement of 0. Menis, Section Chief, Analytical

Chemistry Division.

10
11
12

Li 1

RADIATION PATHLENGTH

SIDE.

FRONT

(TRANSPARENT)

_1_

6

-x TOP MEASUREMENT

LEVEL

I K— 10 N I 12.5 I * II II , T

BOTTOM MEASURMENT

LEVEL

NCIDENT RADIATION BEAM

Figure 3. General shape and nominal dimensions (mm) of NBS

quartz standard cuvette for spectrophotometry.

14
Figure 4a. General view of the standard instrument used

to measure the radiation pathlength of cuvettes.

15
16
IV. REFERENCES

Mavrodineanu , R. , An Accurate Spectrophotometer for

Measuring the Transmittance of Solid and Liquid

Materials, J. Res. Nat. Bur. Stand. (U.S.), 76A,

405-425 (1972)

.

Clarke, F. J. J., High-Accuracy Spectrophotometry, J. Res. Nat. Bur. Stand. (U.S.) , 76A, 375-403 (1972).

Mielenz, K. D., Physical Parameters in High- Accuracy

Spectrophotometry, J. Res. Nat. Bur. Stand. (U.S.), 76A,

455-467 (1972).

Burke, R. W. , Deardorff, E. R. and Menis, 0., Liquid

Absorbance Standards, J. Res. Nat. Bur. Stand. (U.S.), 76A , 469-482 (1972).

Burnett, R. W. , Accurate Measurement of Molar

Absorptivity, J. Res. Nat. Bur. Stand. (U.S.), 76A , 483-489 (1972).

<r U. S. GOVERNMENT PRINTING OFFICE : 1 973 — 5^2-651 /Sh

17

I

FORM NBS-114A (1-71) U.S. DEPT. OF COMM. 1. PUBLICATION OR REPORT NO. 2. Gov't Accession BIBLIOGRAPHIC DATA $P 260-32 N°'

3. Recipient's Accession No.

4. TITLE AND SUBTITLE Standard Quartz Cuvettes for High Accu.T3.cy Spectrophotometry

5. Publication Date December 1973

6. Performing Organization Code

7. AUTHOR(S) R. Mavrodineanu and J. W. Lazar

8. Performing Organization

9. PERFORMING ORGANIZATION NAME AND ADDRESS NATIONAL BUREAU OF STANDARDS DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No.

11. Contract/Grant No.

12. Sponsoring Organization Name and Address

Same as Block 9.

13. Type of Report & Period Covered Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant bibliography or literature survey, mention it here.) Accurate knowledge of lightpath and parallelism of cuvettes

used in spectrophotometry is one of the indispensable parameters

which must be determined when accurate transmittance measurements

of liquid materials is considered,, A description is given of the design and techniques developed at NBS for the production of quartz

cuvettes having a nominal radiation pathlength of 10 mm +_ 0.03 mm. For each cuvette the pathlength and parallelism are certified with

an uncertainty of +_ 0.0005 mm. The method and instrumentation used

to determine these parameters is also described in the paper.

17. KEY WORDS (Alphabetical order, separated by semicolons) Cuvette, spectrophotometry; lightpath; pathlength; quartz, cuvette; radiation pathlength.

18. AVAILABILITY STATEMENT

(XH UNLIMITED.

I I FOR OFFICIAL DISTRIBUTION. DO NOT RELEASE

TO NTIS.

19. SECURITY CLASS

(THIS REPORT) UNCL ASSIFIED

20. SECURITY CLASS

(THIS PAGE) UNCLASSIFIED

21. NO. OF PAGES

27

22. Price$.55

USCOMM-DC 6

NBS TECHNICAL PUBLICATIONS

PERIODICALS JOURNAL OF RESEARCH reports National Bureau of Standards research and development in

physics, mathematics, and chemistry. Comprehensive

scientific papers give complete details of the work,

including laboratory data, experimental procedures, and theoretical and mathematical analyses. Illustrated with photographs, drawings, and charts. Includes

listings of other NBS papers as issued. Published in two sections, available separately:

• Physics and Chemistry (Section A)

Papers of interest primarily to scientists working in these fields. This section covers a broad range of

physical and chemical research, with major emphasis on standards of physical measurement, fundamental

constants, and properties of matter. Issued six times a year. Annual subscription: Domestic, $17.00; Foreign, $21.25.

• Mathematical Sciences (Section B)

Studies and compilations designed mainly for the mathematician and theoretical physicist. Topics in mathematical statistics, theory of experiment design, numerical analysis, theoretical physics and chemistry,

logical design and programming of computers and

computer systems. Short numerical tables. Issued quarterly. Annual subscription: Domestic, $9.00; Foreign,

$11.25. DIMENSIONS, NBS

The best single source of information concerning the Bureau's measurement, research, developmental, co- operative, and publication activities, this monthly

publication is designed for the layman and also for the industry-oriented individual whose daily work

involves intimate contact with science and technology —for engineers, chemists, physicists, research managers, product-development managers, and company

executives. Annual subscription: Domestic, $6.50; Foreign, $8.25.

NONPERIODICALS Applied Mathematics Series. Mathematical tables, manuals, and studies. Building Science Series. Research results, test methods, and performance criteria of building materials, components, systems, and structures. Handbooks. Recommended codes of engineering and industrial practice (including safety codes) de- veloped in cooperation with interested industries, professional organizations, and regulatory bodies. Special Publications. Proceedings of NBS conferences, bibliographies, annual reports, wall charts, pamphlets, etc. Monographs. Major contributions to the technical

literature on various subjects related to the Bureau's

scientific and technical activities. National Standard Reference Data Series. NSRDS provides quantitative data on the physical and chemical properties of materials, compiled from

the world's literature and critically evaluated. Product Standards. Provide requirements for sizes, types, quality, and methods for testing various industrial products. ^.These standards are developed co- operatively with interested Government and industry groups and provide the basis for common understanding of product characteristics for both buyers and

sellers. Their use is voluntary. Technical Notes. This series consists of communications and reports (covering both other-agency and

NBS-sponsored work) of limited or transitory interest. Federal Information Processing Standards

Publications. This series is the official publication within the Federal Government for information on

standards adopted and promulgated under the Public Law 89-306, and Bureau of the Budget Circular A-86

entitled, Standardization of Data Elements and Codes

in Data Systems. Consumer Information Series. Practical information, based on NBS research and experience, covering areas of interest to the consumer. Easily understandable language and illustrations provide useful background knowledge for shopping in today's tech- nological marketplace. BIBLIOGRAPHIC SUBSCRIPTION SERVICES

The following current-awareness and literature-survey bibliographies are issued periodically by the Bureau : Cryogenic Data Center Current Awareness Service (Publications and Reports of Interest in Cryogenics). A literature survey issued weekly. Annual subscription : Domestic, $20.00; foreign, $25.00. Liquefied Natural Gas. A literature survey issued quarterly. Annual subscription: $20.00. Superconducting Devices and Materials. A literature survey issued quarterly. Annual subscription : $20.00. Send subscription orders and remittances for the preceding bibliographic services to the U.S. Department

of Commerce, National Technical Information Service, Springfield, Va. 22151. Electromagnetic Metrology Current Awareness Service (Abstracts of Selected Articles on Measurement

Techniques and Standards of Electromagnetic Quantities from D-C to Millimeter-Wave Frequencies). Issued monthly. Annual subscription: $100.00 (Special rates for multi-subscriptions). Send subscription order and

remittance to the Electromagnetic Metrology Information Center, Electromagnetics Division, National Bureau

of Standards, Boulder, Colo. 80302. Order NBS publications (except Bibliographic Subscription Services) from: Superintendent of Documents, Government Printing Office, Washington, D.C. 20402.
U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, D.C. 20234

OFFICIAL BUSINESS POSTAGE AND FEES PAID

U.S. DEPARTMENT OF COMMERCE COM-215

Penalty for Private Use. $300