1982 Annual Report

Office of Standard Reference

Materials

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, DC 20234

October 1 982

Final

Issued February 1983

Prepared for DEPARTMENT OF COMMERCE

ional Bureau of Standards

shington, DC 20234
I
HATIONAI* BUREAU. OF STANDARDS

LIERARY WAR 1 1 1383

ocAo.cc P~e\

NBSIR 83-2649

l V' -^ 1982 ANNUAL REPORT

OFFICE OF STANDARD REFERENCE

MATERIALS

G. A. Uriano and S. D. Rasberry, Editors

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, DC 20234

October 1 982

Final

Issued February 1983

Prepared for U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, DC 20234

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

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
]IJI
TABLE OF CONTENTS

Page

1. INTRODUCTION

1.1 Special Format for This Report 1

2. UPDATE 1982 (ANAL, CHEM, Pages)

Inventory Status 1226 A

Technology of Certification 1 228 A

International Progress 1235 A

Recently Introduced SRM's ( SR M Production) . . 1 236 A

Metals, Ores, and Minerals 1236 A

Energy Related and Environmental 1236 A

Biological/Botanical Matrix 1241 A

Clinical 1241 A

Thermometry, Spec trop hotometry

,

and Fluorescence 1 242 A

Wear Metals in Lubricating Oil 1 242 A

Microanalysis 1242 A

Radioactivity and Nuclear 1242 A

Trends and Future Emphasis 1244 A

References 1 244 A

3. TECHNICAL ACTIVITIES

3.1 Summary of New and Renewal SRM's 2

3.2 FY82 SRM Sales Report 2

3.3 Data Base Management System 5 3.4 Highlights of Research Projects 5

.1 Radioactivity Research 5

.2 Surface-analysis Methods 6

.3 Chemical Thermodynamics Measurements. . . 9

.4 Measurement of pH 11

.5 Isotope Dilution Mass Spectrometry

of Gases 13

.6 Gases in Metal s 14

.7 Increased Sensitivity in NAA by

Background Reduction 15

.8 High Sensitivity Measurements 17

.9 Analysis of SRM 1649, Urban

Dust/Organics, for the Determination

of Polycyclic Aromatic Compounds 19

.10 Methods for the Determination

ofVitaminsinMilk 20

i
.11 Development of an Isotope Dilution/

Mass Spec tromet r i c Definitive Method

for the Determination of Serum Urea ... 28

.12 Improved Instrumentation for Organic

Isotope Dilution/Mass Spectrometry

Measurements 32

.13 Surface Reactions of Gas Mixtures .... 34

.14 XRD Crystallite Size 39

.15 Chemical Speciati on/Biodeterioration

of SRM 1 s 40

.16 Research on Dye Penetrant,

Microhardness and Thickness SRM's . . . . 43

.17 Glass Standard Reference Materials. ... 44

.18 Catalyst Package for Lubricant

Oxidation Tests 45

.19 Self-Calibrating Gel Permeation

Chromatogr aphy 46

.20 Metallurgical Research 48

.21 Computer Magnetic Media 50

.22 Absolute Layer Thickness Measurements

for Semiconductor Materials 51

4. OSRM STAFF PUBLICATIONS, INFORMATION TRANSFER AND

COMMITTEE ACTIVITIES

4.1 Publications, Journal Articles, and Written

Reports by OSRM Staff in FY82 52

4.2 Technical Lectures/Talks Given by OSRM

Personnel 53

4.3 Standards Committee and Other Standards

Activities . . . . 56

4.4 NBS Special Publication 260 Series 57

4.5 FY82 Technical Exhibits with Staffed

SRM Di sp 1 ays 58
1 . 1 Special Format for This Report

The FY 1982 annual report for the Office

of Standard Reference Materials is notably

different in appearance from previous editions.

This year the Office was honored by the

Analytical Chemistry journal in having the

essential portions of the annual report

published as the cover story for October 1982.

That lead story is reproduced, in section II as the basis of this report. Additional details

are incorporated in subsequent sections.*

* Di sc 1 aimer : Certain commercial equipment, instruments,

or materials are identified in this report

in order to adequately specify the exerimental procedure. Such identification does

not imply recommendation or endorsement by

the National Bureau of Standards, nor does

it imply that the materials or equipment

identified are necessarily the best

available for the purpose.

1

Report

B

Robert Alvarez

Stanley D. Rasberry

George A. Uriano

Office of Standard Reference Materials National Bureau of Standards Washington, D.C. 20234

NBS standard Reference Materials:

update 1982

In 1966, the National Bureau of Standards reported in Analytical

Chemistry (1) the rejuvenation of

its Standard Reference Materials

program. Ten years later an update,

noting considerable progress, was re- ported in Analytical Chemistry

(2). Now, after only six years, so much

has changed in this 76-year old pro- gram that readers of the JOURNAL

may be interested in a status report.

It is the purpose of this REPORT to update the scope and results of this program to 1982 and to provide a glimpse of the future.

The National Bureau of Standards

(NBS) provides several types of ser- vices to scientific, technical, and commercial interests. Among these are

calibration of measuring devices,

Standard Reference Data, and Stan- dard Reference Materials (SRMs). In

analytical chemistry laboratories, the

best known of these services is probably SRMs, since a majority of those is- sued are certified for chemical composition primarily through the efforts of the NBS Center for Analytical Chemistry. In general, SRMs are well characterized homogeneous materials or simple artifacts with specific chemical

or physical properties certified by the

NBS. For 76 years they have been sold by NBS—recently at the rate of about

40 000 per year—to help ensure accu- racy of measurement. More than 80%

of the SRMs distributed are used in industrial measurement applications,

such as maintaining quality control in the production of materials and goods.

Of the 100 largest industrial companies in the U.S., 83 purchased

SRMs in a recent fiscal year (3).

About one-quarter of all SRMs are used outside the U.S. Both domestically and worldwide, SRMs are used in the development of test methods of proven accuracy and to ensure the

long-term reliability and integrity of the measurement process. The devel- opment of new SRMs is frequently a

difficult and expensive proposition.

While the purchasers of the materials

defray production costs, NBS has contributed considerable technological

support and the institutional stability to guarantee continuity of service. Some SRMs (or their renewal counterparts) have been available for more

than 70 years. Earlier papers (J , 2) related the de- velopment of SRMs under the leader- ship of W. Wayne Meinke through

1966 and under J. Paul Cali through

1976. This REPORT will provide an update on the inventory status to 1982. Following brief reviews on tech- nology of certification and progress in international cooperation, most of this REPORT will describe recently issued

SRMs that are of particular interest to

analytical chemists.

Inventory Status

Table I provides an update on the

SRM inventory from the previous

paper (2) to the present. Immediately

apparent is a reduction of 97 SRMs

since the last REPORT. The current

stock of SRM types stands at 870

down from a record high of 1063 in July 1980. The reduction, by and large,

represents “housekeeping” adjustments in the inventory. In such cases, technological changes have rendered

obsolete those SRMs that were dis- continued. In other cases, losses in a given technical capability at NBS

have made it impossible to renew cerTable I. SRM Inventory—1966, 1976,

and 1982

SRMs In Inventory Category 1966 1976 1982

1 . Metals, ferrous 167 219 173

2. Metals, nonferrous 96 98 127

3. Ores, cements, ceramics 28 41 50

4. Organjps, metallo-organics 32 34 22

5. High-purity metals 0 8 10

6. Electron microprobe 0 6 7

7. Primary and secondary

chemicals

10 12 9

8. Microchemicals 5 10 8

9. Clinical 0 21 27

10. Biological and botanical 0 5 9

11. Environmental—gases 3 24 70

12. Environmental—liquids and solids

0 14 28

13. Forensic 0 3 2

14. Fertilizers 0 3 3

15. Glasses 11 30 32

16. Nuclear and isotopic 27 46 38

17. pH, pD, ion-selective 6 17 17

18. Mechanical properties 37 89 40

19. Heat properties 11 64 40

20. Magnetic properties 0 9 16

21. Optical properties 28 31 22

22. Radioactivity properties 37 86 58

23. Miscellaneous physical

properties (incl.) metallurgical, Mossbauer,

X-ray

5 35 14

24. Engineering properties

rubber and polymers

19 21 23

25. Engineering properties

color

35 6 2

26. Engineering properties

other

2 14 10

27. Research materials 0 18 7

28. General materials 0 3 6

Totals 559 967 870

1226 A • ANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982
A panoramic display of approximately 300 of the nearly 900 different SRMs currently certified by NBS

tain SRMs, even in the face of strong

technical demand. These are serious

losses to the program and to the U.S.

technical community.

For the metals and ores (categories

1, 2, 3, and 5) a good balance in inventory has been maintained over the

past 16 years, with gains in the number of types available in all categories

except ferrous metals. In that cate- gory, the net decrease does not repre- sent a serious technological shortfall. Rather, it results from eliminating some duplication and certifying more

elements in fewer materials to cover the same technological needs. Especially since 1976, the Metals Research

Associate Program [conducted jointly

with the American Society for Testing

and Materials (ASTM)] has played a major role in meeting industrial needs

for metal reference materials. The co- operation of ASTM sponsoring Committees E-2, E-3, and E-16 in helping

to select and carry out metal certifica- tion projects has been very valuable in ensuring a strong inventory of metal

reference materials. Another category where an inventory decline should not present serious

This article not subject to U.S. Copyright

Published 1982 American Chemical Society

problems is the metallo-organics cate- gory. There a number of pure materials have been dropped that were for- merly available for synthesizing wearmetal-in-oil standards for individual elements. They are being replaced

with a few multielement-metal-in-oilmatrix SRMs that should serve the same purpose.

In the nuclear and isotopic, radioactivity properties, and mechanical

properties categories taken together, there has been a net decrease of 85 in- ventory types. In general, this reflects an attempt to develop benchmark

SRMs covering only the most important parameters rather than to provide SRMs for every single point of interest. This not only conserves the

program’s financial resources, but also provides additional opportunities for commercial suppliers of reference materials. Category 25, engineering proper- ties—color, will very likely disappear

in the next two years. Centroid color charts and color chart kits remain in

this category, and the technology to renew them is no longer available at NBS.

The area of largest expansion during the past 16 years has been in bio- logical/botanical and environmental

categories (categories 10-12). These

three categories had a combined gain

of 40 types between 1966 and 1976

and a further gain of 64 types between

1976 and 1982. While some expansion

may continue in the biologicals and

botanicals, it seems unlikely that a

similar growth rate will be maintained

in the environmental categories. Good

progress has been made in establish- ing benchmark environmental SRMs.

Overall, since 1976, about 280 new SRMs have been certified (excluding

renewals), and about 380 types have

been discontinued during the same

period.

The fulfillment of customer orders from the SRM inventory was greatly accelerated during May 1982. At that time an improved warehousing of packaged SRMs was implemented and

order processing was transferred to a

real-time computer-based system.

With order placement and printing of packing slips, labels, notifications, and

invoices all automated, shipments of

in-stock SRMs can now be made usuANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982 • 1227 A
• Reference Method

Development and

Evaluation • Production of HighAccuracy Secondary

Reference Materials • Critical Quality Assurance

Applications

• Field Method

Development

and Evaluation • Preparation of Routine

Working Reference

Materials • Routine Internal and

External Quality Assurance

Field Applications

Figure 1. An idealized accuracy-based measurement system, which illustrates the

role of SRMs (primary reference materials) in transferring the accuracy inherent in definitive methods into widespread laboratory use. For a more detailed description, see Reference 10

ally within two days of receipt of

order. This is in marked contrast to former processing times that averaged

two to three weeks.

Further information regarding specific SRMs may be found in the catalog of NBS Standard Reference Materials (4) and in a recent annual report

covering new developments (5). More

frequent updates are published

monthly in a column entitled “Refer- ence Materials” (6). Periodic reports

are also provided to the Association of

Official Analytical Chemists (7). Details on specific new additions to the

SRM inventory are published in indi- vidual releases mailed directly from

NBS to anyone requesting them.

Technology of Certification

NBS is authorized by federal laws

and regulations to certify and sell SRMs that help users link their measurements to national measurement

standards. The role of SRMs in an

idealized systems approach to measurement accuracy is shown in Figure

1. As can be seen from the figure,

SRMs are only one part of a larger

picture. Also essential to obtaining ac- curate analyses are good methods,

good laboratory practices, well-qualified personnel, and adequate quality assurance procedures.

Where possible, NBS certifies numerical values of the properties under

investigation as accurate values. That

is, they are the “true values” within

the stated overall uncertainty limits. During the mid-1970s, considerable

time and effort were invested in refin- ing the technology of certification ISIS). These efforts have been continued into the 1980s with increased in- ternational participation {13-15). In general, four major considerations are involved in certifying an SRM:

Homogeneity. It is essential that every subportion of a given lot be the same within the overall uncertainty

limits provided. This is necessary to ensure that each user obtains a portion of the SRM which agrees, in val- ues certified, with the certificate. Stability. If the material changes

with time (and certainly most materials do to some extent) it will eventually have “true values” that no longer agree with the values printed on the

certificate. Increasingly, SRMs are provided with expiration dates, after which their certificate is not valid. (For example, no clinical SRM is is- sued with a certificate valid for more

than five years.)

Handling Procedures. Special

procedures, such as cold storage,

drying, and other preparation, may be

necessary to the proper use of SRMs.

Such instructions are now provided

routinely when appropriate.

Certified Values. The importance

of accurately analyzing materials so that “true value” numbers can be

placed on the certificate is clear, but

this is our most difficult job at NBS.

We do not claim infallibility. Even

though systematic errors in the measurements leading to certification are always investigated, later advances in the state of the art may uncover errors that were undetected at the time of the original work. Thus, NBS tries to provide conservatively stated uncertainties to allow for unknown systematic errors. Several techniques are

especially helpful in the quest for cer- tification accuracy.

First, although they may be much

too costly for routine use, definitive methods (methods of the highest ac- curacy) are more closely linked to

basic measurement units and thus re- duce opportunities for error. Second,

the agreement of several independent

( continued on p. 1235 A)

1228 A • ANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982
metnods lends assurance to certitica- tion. Further, agreement among several independent laboratories—using

the same or different methods—pro- vides additional reason for confidence.

Assistance in certification is provided

by many independent laboratories. In- creasingly, the coordination of this as- sistance has been accomplished with

the help of the American Society for Testing and Materials, through re- search associate agreements. There

are such agreements in effect in the

fields of metals and ores, glass, and

particle metrology. Additionally, the

cooperation of other associations has

been most helpful. Some of those co- operating in the production of SRMs

are the Atomic Industrial Forum, the

Motor Vehicle Manufacturers Association, the American Iron and Steel Institute, the American Foundrymen’s

Society, and the Portland Cement Association. Information on measurement methods used in SRM certification is fre- quently published in greater detail than can be given in the certificate,

especially when the methods are novel

or modified from standard practice.

The NBS Special Publication 260 Series is dedicated to reporting progress

in the technology of certification. Seventy-seven reports in this series have

been prepared during the past 18

years. The first 49 reports were mentioned in the 1976 ANALYTICAL

Chemistry article (2). Now an additional 28 are categorized in Table II.

international Progress

The last decade has seen a large

growth in reference materials activities, not only at NBS, but also within

many other countries and multinational organizations. In the U.S., more

than 250 new SRMs must be certified

in the next five years, judging from re- quests and proposals already in hand

at NBS. The worldwide demand for certification of new reference materials over the coming decade is probably

numbered in the thousands. Considerable resources must be devoted to maintaining the supply of the thousands of reference materials already

certified. No single organization has

sufficient resources to meet these de- mands on a timely basis. Thus, greater

international cooperation is essential to expedite certification of needed new reference materials and to reduce

unnecessary duplication of efforts. NBS continues to play an important

role in international reference material activities through cooperative

projects involving international stan- dards organizations and professional

societies, as well as through working

arrangements with certified reference material producers in other countries

and in multinational organizations.

The first four SRMs certified by NBS in 1906 were these four cast iron compositional standards prepared in cooperation with the American Foundrymen’s Society

During the past eight years, the In- ternational Organization for Standardization (ISO) has become very active in promoting communication and

cooperation among reference material

programs in various countries through

the work of the ISO Council Committee on Reference Materials (REMCO),

currently chaired by George A. Uriano. REMCO has recently published a

series of documents intended to serve

as guides to the certification and utili- zation of reference materials. One of the most important documents recently issued by ISO is an international

directory of certified reference material producers (16), which identifies hundreds of producers of certified reference materials throughout the

world. The directory was assembled

largely through the efforts of J. Paul

Cali, former chief of the Office of Standard Reference Materials. Another important project recently initiated under REMCO sponsorship in cooperation with ISO TC-69 on Application

of Statistical Methods is the development of a guide describing statistical principles for the certification and use

of reference materials. An international team of statisticians and chemists

has been assembled to draft the docu- ment. NBS has given extensive support to the International Union of Pure and

Applied Chemistry (IUPAC) Commission 1.4 on Physicochemical Measure- ments and Standards. This commission has published a series of recom- mendations for the selection and specification of reference materials for use

in various types of physicochemical measurements. Recommendations of particular interest to analytical chemists include those on reference materials for thermal (17) and optical (18)

properties and potentiometric ion activities (19). NBS is working closely

with other international standardization bodies having active programs in- volving certified reference materials,

including the European Economic

Community, the International Organization for Legal Metrology, the Inter- national Federation for Clinical Chemistry, the International Atomic

Energy Agency, and the World Health

Organization.

NBS has also been engaged in a number of bilateral cooperative

projects with foreign national laboratories that are engaged in the certifi- cation of reference materials. A series of interlaboratory comparison projects

aimed at ensuring the compatibility of measurement methods among various

reference material producers has been

completed. For example, a series of

Table II. Guide to NBS

Special Publications on SRMs

Since 1975®

SRM subject matter Ferrous metals

Information, sources

Glass and ores

Instrumental aspects

Primary chemicals

Physical properties

Polymers

Clinical and health

Serial numbers

In 260 Series

70, 73, 76

57

74

51, 54, 59, 62, 64,

65, 66, 68, 75

53

50, 52, 55, 56, 77

58, 61

60, 63, 67, 69,

71, 72

8 For example, #60 in the second column refers to NBS

Special Publication 260-60 (1978). Its title Is "Standard Reference Materials: A Reference Method for the Determination of Sodium In Serum." Full titles are listed

in the current SRM Catalog.

ANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982 • 1235 A
The ability to control analytical blanks due to external sources of sample contamination is an important requirement in high-accuracy trace analysis. Ellyn Beary is utilizing one of the NBS Clean Room Facilities for preparation of SRM specimens

for trace analysis

analytical gas SRMs for use in envi- ronmental monitoring was exchanged

with the French National Bureau of Metrology (BNM), and analyses were made by both countries on the other’s reference materials to verify the certi- fications. NBS and BNM are also cur- rently completing the joint certifica- tion of a set of octane rating reference

materials.

Finally, NBS has also devoted considerable effort to aiding developing

countries in establishing or improving

reference material certification pro- grams. During the past five years, sci- entists representing Brazil, the People’s Republic of China, Hungary, and

Egypt have worked at NBS for periods

of up to one year to study NBS proce- dures for the preparation and certifi- cation of reference materials. Several

of these countries have greatly ex- panded their reference material certi- fication activities, partly as a result of NBS cooperation. The Institute for Technical Research in Sao Paulo, Brazil, now certifies over 30 metal composition reference materials. The People’s Republic of China has recently

formed a new Center for Reference

Materials within the National Insti- tute of Metrology in Beijing.

The greatly increased worldwide de- mand for certified reference materials

will require even more international

cooperation during the coming decade.

Improved information transfer and

technology transfer will be essential to ensure that these demands are met in an efficient and timely manner.

Recently introduced SRMs

Metals, Ores, and Minerals. Most

metal, ore, and mineral SRMs devel- oped in recent years are a joint effort with industry and ASTM. The justification for such SRMs is provided by

industry, generally through a special

ASTM Coordinating Committee for Standard Reference Materials (S-17).

As for all SRMs, their justification in- cludes evidence of need, unavailability of similar reference materials from

other sources, and information concerning special requirements for the

SRMs, e.g., chemical composition, homogeneity, and form.

Examples of a few especially signifi- cant industrial SRMs are described. A

complete listing of available industrial SRMs is given in the NBS SRM catalog (4). Tracealloy: Nickel-Base HighTemperature Alloy. SRMs 897-899

are certified for Pb, Se, Te, and Tl. The presence of these elements at trace concentrations in nickel-base al- loys affects their performance in highstress high-temperature applications,

such as gas turbines. Unalloyed Copper Benchmark

SRMs. Impurity elements and their

concentration levels in refined copper

have a profound effect on such properties as electrical and thermal conductivity, which in turn affects product performance in a number of energy-related applications. For example, the presence of as little as 50 pg/g

of Fe in copper wire can reduce the

electrical conductivity by as much as 4%. Chemical composition specifica- tions for unalloyed copper products

have become so severe that disagreements among producers and consumers have resulted. Copper SRMs provide concentration ranges for approximately 13 trace elements.

Zirconium Metal and Zircaloy-4

Alloy. Because of its high-capture

cross section for neutrons, the pres- ence of hafnium in zirconium and its alloys adversely affects the operating

efficiency of nuclear power plants.

Therefore, hafnium must be reduced

to pg/g levels in these reactor-grade

materials. However, the difficulty of determining trace concentrations of hafnium has led to disagreements be- tween producers and users of such materials. Recently, a newly developed

isotope-dilution spark source mass

spectrometric procedure has produced

results for hafnium in agreement with neutron activation analysis. This has

enabled NBS to add hafnium to the

certification of these materials. Reduced Iron Ore ( SRM 691 ). Reduced iron oxide is an important in- termediate in the making of steel by

the electric-furnace method. The pro- duction and certification of a stable and homogeneous reduced iron oxide

reference material for metallic iron, total iron, and other elements have

proven to be formidable problems

during the last decade. NBS SRM 691

represents the first certified material

of this kind. It supplements four additional iron ore SRMs.

Energy-Related and Environmental SRMs. Some constituents

present in coal and other fuels are potentially injurious when released into the environment. These include ele- ments such as mercury, cadmium, and

lead; organic compounds present naturally in oil, such as polynuclear aro- matic hydrocarbons (PAHs); and oil contaminants such as polychlorinated

biphenyls (PCBs). A series of environmental SRMs was developed to pro- vide certified concentrations of envi- ronmentally important inorganic and

organic constituents. The SRMs in- clude fossil fuels, water, sediments,

urban dust, and biological matrices. In

addition, a series of gas mixtures and

permeation tubes is available that is useful in monitoring stationary and

mobile sources of pollutants. Special

nuclear materials and radioactive

SRMs have also been developed.

Coals—Bituminous and Subbituminous. Two coals are available that are

certified for chemical composition in- cluding elements present at trace levels such as the priority pollutants, Cd,

Cr, Cu, Ni, Pb, and Zn. The subbituminous coal (SRM 1635) is certified for 14 elements, the bituminous coal (SRM 1632a) for 19 elements.

Many of these elements are concentrated in the particulate fly ash. Al1236 A • ANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982
I. Lynus Barnes operates an NBS high-accuracy mass spectrometer used together

with isotope dilution techniques for certification of inorganic constituents in a wide

variety of SRMs

though fly ash can be removed by elec- trostatic precipitators, its storage and

disposal have environmental conse- quences. Coal fly ash, SRM 1633a,

which is certified for 20 elements, has

been issued for use in validating data

and methods for this material. Fuel Oils and Reference Fuel. A se- ries of residual and distillate fuel oils (SRMs 1619-1624) provides certified sulfur concentrations ranging from 0.1 to 5% nominal. A commercial “No. 6”

residual fuel oil, certified for S, Pb,

Mn, Ni, Se, Na, V, and Zn, is available

for use in assessing the reliability of these analytical determinations. Ref- erence fuels with certified concentrations of lead are also available. Shale Oil. A shale oil SRM was de- veloped primarily for evaluating the accuracy of analytical methodology in an oil matrix. Based on agreement of two independent methods, certified concentration values are provided for nine trace organic constituents of en- vironmental concern, including fluo- ranthene, benzo [a] pyrene, perylene,*

and phenol.

Polychlorinated Biphenyls in Oil (SRM 1581). The widespread use, persistence, and reported toxic effects of PCBs caused the Environmental Protection Agency (EPA) to ban their manufacture and use under provisions

of the Toxic Substances Control Act. Handling and disposal of materials

containing PCBs depend on the PCB

concentration. Fluids containing 50

pg/g or more of PCBs are subject to controlled disposal. To aid in analysis

of such oils, SRM 1581 has been certified. It consists of Aroclors 1242 and

1260 present individually at 100 pg/g

in motor oil and transformer oil. Additional base oil is supplied as a diluent. Water. Five SRMs have been devel- oped for the analysis of water—three

for the determination of inorganic

constituents and two for organic compounds. SRM 1643a simulates the ele- mental composition of natural fresh water. It was prepared by adding

known amounts of 21 elements to high-purity water, including 17 at ng/g

(ppb) levels. Two additional SRMs for mercury at pg/g and ng/g levels in water have been especially prepared to assure stability.

Considerable effort has also been

devoted to developing a new class of SRMs for use in determining trace

toxic organics, such as PAHs. However, solutions containing known concentrations of PAHs in water are unstable. Therefore, an unusual system

in the form of “generator columns”

(SRM 1644) was developed to enable

the user to accurately generate aqueous concentrations of three PAHs

anthracene, benz [a] anthracene, and

benzo[a] pyrene (20). These com- pounds represent three-, four-, and

five-condensed-ring structures, re- spectively, and are priority pollutants. Accurate concentrations of these lowsolubility compounds, which range from 1 to 50 Mg/kg (ppb), are difficult to achieve by other techniques.

Solutions of PAHs in acetonitrile are stable when present at higher levels. Accordingly, an acetonitrile solu- tion containing known concentrations

of 16 PAHs, identified as EPA priority

pollutants, was prepared, ampouled,

and analyzed by high-performance

liquid chromatography and gas chro- matography. The PAHs are present at pg/mL levels in SRM 1647. Because of the miscibility of acetonitrile with

water, the SRM is particularly useful

in fortifying aqueous samples. In addition to providing certified concentrations and estimated uncertainties for the PAHs, the certificate for SRM

1647 gives ultraviolet absorption data

between 205 and 600 nm as an aid in identifying the compounds.

Sediments. Two new sediments

have been developed—a river sedi- ment (SRM 1645) and an estuarine

sediment (SRM 1646). The concentrations of the environmentally important elements in the estuarine sedi- ment are much lower than those in the

river sediment, which came from a

highly industrialized area. The estuarine sediment is also certified for nutrient elements and should prove useful to marine biologists.

Urban Dust. Two urban particulate

SRMs are available. The certificate of

analysis for SRM 1648, which was re- vised in 1982 to include additional

characterization, lists certified concentrations of eight inorganic priority

pollutants: arsenic, cadmium, chromium, copper, lead, nickel, selenium,

and zinc. An additional six elements

are certified, while noncertified values

are provided for 22 elements. In 1982, a second urban dust (SRM

1649), certified for five PAHs, was is- sued. The compounds, all priority pollutants, and present at pg/g levels in the material are: fluoranthene, benz[a] - anthracene, benzo [a] pyrene, benzo[ghi] perylene, and indeno[l,2,3-cd]- pyrene. In addition, information is provided on the concentrations of 9

organic compounds, 24 elements, and

4 leachable anions. Gas SRMs of Certified Composition

and Permeation Devices. There are now more than 60 gas SRMs certified for use in analysis of gaseous pollutants. These SRMs provide a wide

range of compositions of oxides of ni- trogen, carbon, and sulfur and hydrocarbons in either an air or nitrogen

matrix. Twenty-five of these SRMs

were developed in a two-year cooperative program with the Motor Vehicle

Manufacturers Association. The heavy

demand for gas SRMs has resulted in NBS cooperating with EPA to establish a procedure for assuring traceability of commercially produced certified reference materials to SRMs

from NBS (12). NBS has under development a new

series of organic constituent permeation tubes and cylinders. The first to be introduced will be benzene in nitro- gen gas and a benzene permeation

tube.

ANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982 • 1239 A
Ryna B. Marinenko operates an electron microprobe used for quantitative evaluation of microhomogeneity of SRMs such as SRM 470, mineral glasses

Biological/Botanical Matrix

SRMs. The importance of reliably de- termining elements in plant and ani- mal tissues continues to increase as re- searchers seek to establish optimum

levels for nutrient elements in the diet and to assess the effect of elements

thought to be toxic. Nine biological-matrix SRMs are now available from NBS to aid in as- sessing the accuracy of elemental analysis in biological and botanical matrices. The certificates of analysis for these SRMs list certified concentrations of nutritionally and environmentally important elements.

Four SRMs are available for use in assessing the accuracy of plant tissue analyses. They are orchard leaves (SRM 1571), citrus leaves (SRM

1572), tomato leaves (SRM 1573), and

pine needles (SRM 1575).

Two animal tissue SRMs are avail- able: oyster tissue (SRM 1566) and

bovine liver (SRM 1577a)—a renewal

of SRM 1577. SRM 1566 was devel- oped because of concern about con- tamination of marine animals used as foods. A number of marine animals,

especially bivalves, are known to concentrate heavy metals and other substances from their aquatic environ- ment. Some species of oysters and

mussels exhibit this property to such a marked degree that scientists have

proposed their use as sentinel organ- isms for monitoring pollutant levels in coastal marine waters. Accurate data on the pollutant levels in such bivalves can be obtained efficiently by analyzing the samples relative to a similar marine animal tissue in which concentrations have been certified for the

elements of interest.

The certificate of analysis for the new bovine liver material (SRM

1577a) lists certified concentrations

for elements that were not certified in the original bovine liver. In all, 22 el- ments are now certified in SRM

1577a. Brewers yeast, SRM 1569, is certi- fied for Cr at 2.12 ± 0.05 ng/g. Cr de- terminations are of special interest to

nutritionists because Cr is an essential element and plays an important role

in the maintenance of normal glucose

tolerance. A wheat flour (SRM 1567) and a

rice flour (SRM 1568) have been characterized mainly for trace elements of

nutritional and environmental interest. The chemical composition of cereal foods is of special interest to envi- ronmentalists, medical researchers,

and food scientists because of the

large consumption of such foods

throughout the world. Because of the

interest in the accumulation of Pb in food products, Pb was determined in the two flour SRMs.

Stabilized Wine. Disagreements

have occurred regarding the ethanol content of wines. These differences may be attributable to discrepant analytical results among laboratories. Because of the difficulty of validating

ethanol determinations, the American

Society of Enologists suggested and

cooperated in the development of a

stabilized 18% ethanol wine SRM.

Clinical SRMs. A number of new

clinical SRMs have been developed for use in determining the accuracy of

clinical data, methods, and commercially produced reference materials; in calibrating instruments and testing

their performance; and in correlating

and comparing clinical data from lab- oratories using different methods and

instruments.

The clinical SRMs may be classified into three general types:

• human serum matrix materials with

accurately certified constituents;

• high-purity organic and inorganic

compounds for preparing solution cal- ibrators or spiking matrix solutions; and

• instrument-performance SRMs.

NBS has certified three human

serum SRMs. SRM 909 is certified for electrolytes and organic constituents

at “normal” levels in human serum. At

present, the certificate lists certified concentration values for calcium, chloride, cholesterol, glucose, lithium,

magnesium, potassium, and uric acid. Urea and total protein have also been

determined and their concentration

values will be added to a revised certificate upon completion of the statis- tical evaluation. All of these constitu- ents were determined using isotope

dilution mass spectrometric procedures, considered definitive methods because of their high accuracy. The certificate for SRM 909 also provides information-only values of the catalytic concentrations of seven enzymes. The enzymes, for which definitive methods are not available, were determined cooperatively by

teams of experts using “best avail- able” methodology. Where possible,

methods of the International Federation of Clinical Chemistry or the

American Association for Clinical Chemistry were used. The certificate provides outlines of the methods and

the final assay reaction conditions and

gives literature references. A human serum matrix (SRM 900)

certified for subtherapeutic, therapeutic, and toxic concentrations of four antiepilepsy drugs—phenytoin, etho- suximide, phenobarbital, and primidone—has also been issued. This

SRM was developed in response to a survey indicating inaccurate drug levels being reported by the majority of

laboratories surveyed (21). The certi- fication of SRM 900 has been de- scribed in detail (22). SRM 1599 is a second human serum matrix that contains certified concentrations of two

other widely used antiepilepsy

drugs—valproic acid and carbamazepine. A number of clinically important

organic and inorganic compounds certified for purity are also available. In addition, there are miscellaneous

clinical SRMs, such as a bovine albu- min material in either a high-purity

powder or a 7% solution form, which

conform to applicable specifications of the National Committee for Clinical Laboratory Standards. SRM 938, 4-

ANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982 • 1241 A
A Fourier transform infrared spectroscopy system is being operated by Reenie

Parris. This technique is being used to determine the identity of individual PCB iso- mers in SRM 1581

nitrophenol, was developed for use in spectrophotometric procedures where

4-nitrophenol is the chromogenic com- pound formed.

A summary of the technical specifications for over 30 NBS clinical SRMs

has been prepared (23). SRMs for Thermometry, Spectrophotometry, and Fluorescence

Spectrometry. Chemical reaction

rates such as those involving enzymes

are very sensitive to small temperature changes. Thus, accurate measure- ment of reaction temperature is an important step in the analytical procedure. For validating temperature measurements, a gallium melting point

thermometric device (SRM 1968) is available with a certified melting

point of 29.7723 °C. A clinical labora- tory thermometer with calibrated

points at 0°, 25°, 30°, and 37 °C is also

available. Nearing completion is a rubidium

melting point thermometric device for Calibrating thermometers accurately near 37 °C. SRMs have been developed to veri- fy the accuracy of the transmittance

and absorbance scales of spectrophotometers. The SRMs consist of glass

filters (SRM 930d and SRM 2030),

metal-on-quartz (SRM 2031), liquid

filters (SRM 931c), and crystalline po- tassium dichromate for use in solution form as an ultraviolet absorbance cali- brator (SRM 935). A crystalline potassium iodide of known purity (SRM

2032) is available for assessing hetero- chromatic radiant energy (stray light) in ultraviolet spectrophotometers

below 260 nm. The specific absorb- ance of an aqueous solution of KI is certified at eight wavelengths, in 5-nm

intervals from 240 to 275 nm. Stray

light in UV spectrophotometers is as- sessed by comparing the certified val- ues of specific absorbance to the absorbance values of aqueous solutions

of SRM 2032 measured under conditions of known concentrations, pathlength, and temperature.

Didymium glass filters (SRMs 2010

and 2013) are available for use in cali- brating the wavelength scale in the

visible region of spectrophotometers

having nominal bandwidths in the range of 1.5 to 10.5 nm. The wavelengths of maximum absorption were

determined with a high-precision

spectrophotometer for 14 to 24 wavelengths in the range of 400 to 760 nm. The instrument has a wavelength ac- curacy of 0.04 nm.

For calibrating fluoresence spec- trometers, a quinine sulfate dihydrate

material (SRM 936) was analyzed for impurities, and a solution of SRM 936

in perchloric acid is certified for the

relative molecular emission spectrum,

from 375 to 675 nm for an excitation wavelength of 347.5 nm.

Wear Metals in Lubricating Oil. Incipient engine failure can be detect- ed by monitoring the concentrations

of bearing metals in the engine oil. Two SRMs have been certified for use

in the calibration of instruments and

evaluation of methods for the analysis of engine lubricating oils for wear- metal content. The SRMs consist of metallo-organic compounds blended

into a base oil at nominal levels of 100

ppm for SRM 1084 and 300 ppm for SRM 1085. The certificates of analysis

will list certified concentration values

for Al, Cr, Cu, Fe, Pb, Mg, Mo, and Ni. SRMs for Microanalysis. SRMs

have been developed to provide homogeneous materials suitable for quantitative microanalytical methods such

as electron probe microanalysis, sec- ondary ion mass spectrometry, spark

source mass spectrometry, and laser probe analysis. They include: SRM

479, a single-phase alloy (austenitic)

containing 71.0% Fe, 18.3% Cr, and

10.7% Ni; SRM 480, a tungsten-20%

molybdenum alloy; SRM 481, goldsilver alloys; SRM 482, gold-copper

alloys; SRM 483, an iron-3% silicon

alloy; and SRM 470, two glasses, certi- fied for Si(>2, FeO, MgO, and CaO

(one is also certified for AI2O3). In addition, two SRMs are available

for use in evaluating the performance

of scanning electron microscopes

(SEMs). SRM 419 is for evaluating

the SEM resolution; SRM 489b is for use in calibrating the SEM magnification scale to an accuracy of 5% or better within the range of 1000-20 000X. Radioactivity and Nuclear

SRMs. Radioactivity SRMs are avail- able that are certified for the activity of the radionuclides. These SRMs in- clude radiopharmaceutical SRMs,

such as gold- 195, and natural matrix

materials such as a soil (SRM 4353)

and a river sediment (SRM 4350b)

collected from the vicinity of a nuclear

reactor facility. The concentrations of

fission and activation products in SRM 4350b are higher than those

found in other areas in the world. The

radionuclides 239Pu, 240Pu, and 241Am

are very homogeneously distributed,

and the inhomogeneity is 3% or less for other radionuclides. Other natural matrix radioactivity

SRMs are being certified. They are: a human liver material (SRM 4352) certified for alpha-particle emitters; a Peruvian soil, which has very low levels of activation and fission products;

and a lake sediment, which has a high content of organic matter and contains fission and activation products.

SRMs have been developed for use

in nuclear energy production. These

include: plutonium materials certified for Pu content, trace elements, and

isotopic abundance; uranium materials certified for uranium concentration and isotopic abundance; a neutron density monitor wire SRM; and

fission track glass standards. Some

nuclear SRMs were developed in co- operation with the Department of Energy, New Brunswick Laboratory, and

the University of California, Los Ala- mos National Laboratory. The New

Brunswick Laboratory is now responsible for distributing nuclear SRMs.

1242 A ® ANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982
Trends and Future Emphasis

Until 1966, nearly all SRMs were

compositional standards (primarily

certified for bulk constituents or purity), designed for use in quality control systems during mining and manufacturing of raw and processed industrial materials. The SRM inventory

primarily consisted of metal-bearing

ores, metals and alloys, cement, glass,

and inorganic chemicals. In 1969, SRM development and

production activities were involved in only six NBS technical divisions with

over 90% of the production occurring

in the NBS Analytical Chemistry Division. At that time, NBS management recognized that SRMs could

serve as an important mechanism for transferring the output of a broad

spectrum of NBS measurement pro- grams, including physical and engineering measurements as well as chemical measurements, to the user community.

By 1980, the Standard Reference

Materials program was considerably

strengthened through the participa- tion of 23 technical divisions within

NBS. This enabled NBS to increase

the number of SRMs by over 500 (i.e., by nearly 100% in 14 y). Included were SRMs in many new areas such as computer technology, fire safety, forensic

science, and radiopharmaceuticals,

with recent emphasis on the two important areas of environmental and

clinical measurements. Through the mid-1980s emphasis

will be given to research and production projects leading to new SRMs

certified for organic as well as inorganic constituents, particularly in natural matrix materials of environmental,

clinical, or nutritional interest. Future emphasis also will be placed on inor- ganic ultratrace constituents and on

species-specific certification. In the

latter case, research problems to be re- solved are formidable.

Another area of special emphasis

during the next three years is the re- newal of the SRM 1260 series for lowalloy steel composition. The current

series of materials provides a foundation for quality control in steel pro- duction around the world. The renewal program, costing about $500 000,

wili provide enough additional SRMs

to meet expected demand through the

1990s. Microdimensional characterization,

which will be a growth area for physical property SRMs, is also of special

interest to analytical chemists. Here,

small particles, some with diameters

less than 1 /um, will be certified as cali- brants for particle size measuring and

counting apparatus. The certification of the chemical composition of sur- faces (compositional mapping) is also

an important need to be met in tne iuture.

References

(1) “The NBS Standard Reference Materials Program,” Anal. Chem. 1966, 38

(8), 27A.

(2) Cali, J. P. “The NBS Standard Refer- ence Materials Program: An Update,”

Anal. Chem. 1976, 48, 802A.

(3) “Standard Reference Materials”; In- formation booklet available from the Office of Standard Reference Materials, National Bureau of Standards, Washington, D.C. 20234 (1982).

(4) “Catalog of NBS Standard Reference

Materials,” 1981-83 ed.; NBS Special Publication 260; Government Printing

Office: Washington, D.C.

(5) “1981 Annual Report—Office of Stan- dard Reference Materials”; Uriano, G.

A.; Rasberry, S. D., Eds.; NBSIR 81-

2447; National Bureau of Standards: Washington, D.C., 1981.

(6) “Reference Materials”; Rasberry, S. D., Ed.; monthly column appearing in Am.

Lab. 12, 13, 14, June 1980 to present.

(7) Alvarez, R. “Report on Reference Materials and Standard Solutions,” J. Assoc. Off. Anal. Chem. 1980,63 (2); 1981, 64 (2); 1982, 65 (2). (8) “Proceedings of the Symposium on

Standard Reference Materials and

Meaningful Measurement”; Seward, R. W., Ed.; NBS Special Publication 408; Government Printing Office: Washington, D.C., 1975.

(9) Cali, J. P. et al. “The Role of Standard

Reference Materials in Measurement

Systems”; NBS Monograph 148; Govern- ment Printing Office: Washington, D.C.,

1975.

(10) Uriano G. A.; Gravatt, C. C. “The

Role of Reference Materials and Methods in Chemical Analysis,” Anal. Chem.

1977, 6, 361.

(11) Cali, J. P.; Reed, W. P. “The Role of NBS Standard Reference Materials in Accurate Trace Analysis”; NBS Special Publication 422; Government Printing

Office: Washington, D.C., 1976.

(12) Hughes E. E.; Mandel, J. “A Proce- dure for Establishing Traceability of Gas

Mixtures to Certain NBS SRMs”;

NBSIR 81-2227; National Bureau of Standards: Washington, D.C., 1981.

(13) “Production and Use of Reference

Materials”; Schmitt, B. F., Ed.; Proceedings of the International Symposium

held at Bundesanstalt fur Materialpriifung, Berlin 45 Federal Republic of Germany, 1980.

(14) “Terms and definitions used in con- nection with reference materials”; ISO

Guide 30-1981 (E); Available from American National Standards Institute, 1430 Broadway, New York, N.Y. 10018 (1981).

(15) “Contents of certificates of reference

materials”; ISO Guide 31-1981 (E); Available from American National Stan- dards Institute, 1430 Broadway, New

York, N.Y. 10018 (1981).

(16) “Directory of Certified Reference Materials (CRM): Sources of Supply and

Suggested Uses”; International Organization for Standardization: Geneva;

Available from American National Stan- dards Institute, 1430 Broadway, New

York, N.Y. 10018 (1982).

(17) Pure Appl. Chem. 1974, 40, 339.

(18) Pure Appl. Chem. 1974,40,463.

(19) Pure Appl. Chem. 1978, 50, 1485.

(20) May, W. E. et al. “Proceedings of the Ninth Materials Research Symposium”;

NBS Special Publication 519; 1979, p

219.

(21) Pippenger, C. E. et al. Arch. Neurol.

1976, 33, 351.

122) rteeaer, ju. d., er ai. Anuepnepay

Drug Level Assay Standard”; NBS Special Publication 260-72; 1981.

(23) Seward, R. W.; Mavrodineanu, R. “Summary of Clinical Laboratory Standards”; NBS Special Publication 260-71;

1981.

Alvarez

Rasberry Uriano

Robert Alvarez is project manager for

clinical, biological, and water pollution SRMs in the NBS Office of Standard Reference Materials. He ob- tained his BA degree in chemistry in 1942 from the College of the City of New York. As a research chemist, he

has made a number of significant

contributions to analytical chemistry,

particularly in the areas of emission

spectrometry, X-ray spectrometry,

and isotope dilution spark source MS.

Stanley Rasberry obtained the AB

degree in physics from Johns Hopkins University in 1963 and is cur- rently deputy chief of the NBS Office of Standard Reference Materials. One

of the codevelopers of the RasberryHeinrich model to correct X-ray spectra for interfering elements, Rasberry

has also contributed to the development of about 50 SRMs.

George Uriano received his BA and

MS degrees in physics from the University of Connecticut in 1961 and

1962, respectively. He is currently

chief of the NBS Office of Standard

Reference Materials. In his 20-year tenure at NBS he has led research

projects involving the magnetic properties of materials and has also aided

in the planning and management of major NBS programs involving materials science and chemistry.

1244 A • ANALYTICAL CHEMISTRY, VOL. 54, NO. 12, OCTOBER 1982
3. TECHNICAL ACTIVITIES

3 . 1 Summary of New and Renewal SRM's

Table 3.1 summarizes the number of new and renewal SRM's

produced in FY82 as distributed over major program categories.

Fifty-three new and 110 renewal SRM's were completed with the

largest number being in the metals, radioactivity and

env i ronment al categories.

Highlights covering the year's research activities are given

in part four of this section. Issuances of new and renewal SRM's

were recapped in section two: UPDATE 1982.

3 . 2 FY82 SR M Sales Report

Table 3. II summarizes SRM sales in terms of units,

production income and total income for the year ending

September 30, 1982. The gross income of $3,837,698 was a record

high for the program, exceeding last year's figure by 10.5%.

The 39,523 units sold is a decrease of 1.9% relative to last year.

During FY82, over 10,000 orders and 4,000 technical

inquiries were processed. A comprehensive evaluation of all

SRM's in inventory resulted in $163,500 worth of material being

obsoleted, which is less than two percent of the value of the

inventory plus wor k - i n -proc es s . At the end of FY82,

approximately 225,000 sales units of SRM's were carried in

inventory with an asset value of $7,718,000 (including other

agency costs) and a market value of over $20,000,000.

2
Table 3.1

SRM's Produced in FY 1982

Category New Renewal

s

Total

INDUSTRIAL

Metal s 20 2 22

Nonmetal s 2 2 4

Chemical s/Rubber /Plastic 3 5 8

Engi neeri ng 1 28 29

Radioactivity 4 28 32

Subtotal 30 65 95

ENVIRONMENTAL

Gases 7 8 15

Li qui ds/Sol i ds 6 15 21

Subtotal 13 23 36

HEALTH 1 6 7

SCIENCE/METROLOGY 9 16 25

TOTALS 53 110- 163

3
Table 3. II

FY 82 SRM Sales by Category

Units

Total

I ncome*

INDUSTRIAL

Met a 1 s 12,527 931,308

Nonmetals 4,563 318,401

Chemi cal s/Rubber/ 4,810 359,850

Plastic

Eng i neer i ng 6,895 659,123

Radioacti vi ty/ 1,704 353,766

Nuclear

Subtotals 30,499 2,622,488

ENVIRONMENTAL 4_i_162 718.523

HEALTH 3.669 369.405

SCIENCE/METROLOGY 783 90.413

GM/RM 410 36.909

TOTALS 39.523 3.837.698

*Includes income collected for other agencies and other factors.

4
3 . 3 Data Base Management System

The new COBOL programs for use in processing SRM orders and

inventory control was put on-line using the T I 990/12

minicomputer in March 1982. On May 3, 1982, testing was

completed to the point that dual processing on the batch-loaded

computer was discontinued and all customer service was operated

in real-time mode. This had considerable impact on speeding up

delivery to customers. Shipments which formerly had required two

to three weeks after receipt of order are now being sent out in

two to three days. The new system has also facilitated

monitoring levels of packaged stock and a reduced stock-out rate

has been observed

.

Software other than customer support has also been developed.

The new programs support management through better information

regarding inventory trends and by keeping track of the

information pertinent to SRM project selection. Computer

programs will be developed in FY83 to provide rapid tracking of

the status of work in process for active projects.

3 . 4 Highlights of Research Projects

This section describes SRM research highlights during FY82.

Thirty-five SRM research projects were active during the year in

eighteen different NBS divisions. Rather than provide a complete

review, some projects are highlighted here.

. 1 Radioactivity Research

B. M . Coursey, A. T. Hirshfeld, F. J. Shima and

J.M.R. Hutchinson

Nuclear Radiation Division

Center for Radiation Research

An activity calibration of selenium-75 by 4ire-Y coincidence

of anticoincidence methods is complicated by the presence of an 18-ms isomeric level. Present apparent discrepancies with the

calibrations of other national standardizing laboratories can be

traced to different estimates of the extra delayed counts due to

decays from this level. Preliminary measurements with our

anticoincidence system have shown that this contribution can be

measured directly by using very long, accurately known dead times

to block a calculable fraction of the extra counts. This method

is now being applied in an intercomparison of activity

measurements with OMH , Hungary.

The reproducibility of the gaseous mixed-radionuclide

SRM 4310 was checked with a germanium gamma-ray spectrometry

system. The SRM is prepared by mixing krypton-85, xenon-127, and

xenon-133g, with each component separately measured as to

5
activity with a calibrated ionization chamber. For two prototype

sources and two of the SRM's, the gamma-r ay-emi ssi on rates at six

energies were measured with the spectrometry system to check the

quantitative mixing of the three gases. The detection

efficiencies at each energy were calculated and found to have

standard deviations of the mean from 0.29 to 0.92 percent,

sufficient to demonstrate the quantitative metering of the gases

within the counting statistics possible. Additionally, an efficiency curve was fitted to the data, after cascade summing

was corrected. This curve allows a more accurate assay of a xenon-131m impurity, and should prove useful for the

investigation of short-lived noble gases in this bulb geometry.

Developmental work was completed on the Columbia River

Sediment and Peruvian Soil and SRM's of both were issued in FY82.

The transuranic radionuclides were found to be extremely

homogeneous in both materials and could be extracted by acid

leaching methods. Peruvian Soil should be used by many people as

a blank, for the man-made radioactivity concentrations were found

to be two orders of magnitude below those found in the Columbia

River material. For the Peruvian Soil, in addition to

certification of 11 radionuclides and non -cert i f i ed measurement

of 5 radionuclides, trace element concentrations for 57 elements

are given, based on IAEA intercomparison results.

. 2 Surf ace-analysi s Measurements

C . J . Powe 1

1

Surface Science Division

Center for Chemical Physics

(1) Measurement of Absolute Ion Sputtering Yields

(J. Fine and T. D. Andreadis)

The principal aim of this work is to obtain absolute

sputtering yields of 1-5 keV ions on well-characterized elemental

samples in order to improve accuracy of depth -prof i 1 i ng

measurements by current s u r f ace - an a 1 ys i s methods. The accuracy

of d ep t h -pr of i 1 i n g measurements is at present limited by the

unavailability of accurate, reliable sputtering yield data and by

the lack of knowledge of the topographical and morphological

effects produced by ion bombardment.

The use of quart z-osc i 1 1 ator techniques to measure mass loss

due to ion bombardment can result in very accurate determinations

of ion-sputtering yields. In addition to the third-harmonic

oscillator method developed at NBS, another system (operating in

the fundamental mode) has been developed at the J. Stefan

Institute in Ljubljana, Yugoslavia as part of a joint

U.S. /Yugoslavia program and is presently in operation.

6
Measurements are being made using the quartz-oscillator

facilities in Ljubljana to determine absolute sputtering yields

of Ni and Cu using multilayered thin-film targets. These films

are similar in structure to the Ni/Cu Standard Reference

Materials we recently have produced and this yield data will form

part of our SRM characterization. Preliminary results indicate

that the sensitivity of the method is quite adequate for

determining the yields of Ni and Cu, metals for which the

measured yields differ by only about 10 percent.

This type of yield determination will be extended to all of

our SRM materials (Ni, Cu, Ag, Ta 205 ) and will also be made using

the actual SRM structures. Similar measurements will be made at

NBS with our t h i r d - h armon i c method on these SRM's as well as on

i n - s i t

u

prepared elemental targets. Comparison of results

obtained by both systems will allow assessment of the absolute

accuracy of the yield measurement.

(2) Development and Production of Standard Reference Materials

(J. Fine, T. D. Andreadis and F. Davarya)

The objective of this project is to develop standard

reference materials that would allow convenient determinations of

ion-beam sputter-removal rates in commonly used surface-analysis

instrumentation. Thin film reference materials of known

thickness would be used to calibrate ion-gun current densities

for particular operating conditions. This information together

with sputter ing-yi eld data for a range of materials would

establish depth scales in the measurement of depth profiles.

As part of a joint U.S. /Yugoslavia program between J. Fine

at NBS and B. Navinsek at the J. Stefan Institute in Ljubljana,

three prototype thin film structures have been fabricated by

sputter-deposition in Yugoslavia: 1) a thin film oxide of

tantalum produced by reactive sputter deposition onto an i n-si tu

sputtered silicon substrate, 2) a multilayered Ni/Cr/Ni/Cr ... thin-film structure where the layers are about the same thickness

(^70 nm), and 3) a multilayered Ni/Ag/Ni/Ag ... structure where

the Ag layer is considerably thinner than the 50 nm Ni layer.

These structures were also deposited onto quartz oscillators so

that sputtering yield measurements can be obtained by the

mass-loss method. Sputter d ep t h -prof i 1 e analysis using Auger

spectroscopy and x-ray fluorescence has been completed on the

Ni/Cr system; this work has demonstrated the suitability of this

material for use in sputter-profile calibration. The Ni/Ag

system, on careful analysis, has been shown to be subject to

sputter-enhanced Ag surface segregation which can alter its depth

distribution (see (3) below). A modified Ni/Ag thin film

structure was fabricated incorporating a much thinner Ag film

(^3-5 nm) in order to take advantage of the Ag segregation to

improve the interface resolution of these Ag "marker" layers.

7
In addition to the analysis of these materials at NBS, some

20 sets of the three th in -film structures have been distributed

through ASTM Committee E - 4 2 on Surface Analysis. Results of

these measurements, made by a variety of techniques

( Auger -el ectron spectroscopy , secondary-ion mass spectroscopy

,

Rutherford b ac k sc at t er i n g spectroscopy, and proton- i nduced x-ray

emission) to characterize the uniformity, periodicity, thickness,

and stoichiometry of the films and their interfaces are in good

agreement with those obtained at NBS. In collaboration with

Drs. D. Simons and M. Brown of the Naval Surface Weapons Center

at White Oak, Md . , Rutherford backscatter i ng spectroscopy and

proton-induced x-ray emission are being evaluated for use in the

non -destruct i ve analysis of a large number of specimens of the

actual SRM production.

Using the spu tter -depos i t i on facility at the J. Stefan

Institute in Ljubljana, a stock of th in-film SRM's has been

fabricated. About 200 sets, each consisting of four different

structures (Ni/Cr, Ni/Ag, Cr/Cr 203 , and Ta 205 ) will be available

for distribution through NBS. Characterization of these specific

materials will be necessary in order for NBS to certify their

structure and thickness.

(3) Sputter - Induced Surface Segregation at Ni/Ag Interfaces

(J. Fine, T. D. Andreadis and F. Davarya)

The analysis of solid/solid interfaces by ion-beam sputter

profiling in conjunction with surface analysis can result in a significantly broadened composition-depth distribution of the

sputter interface. Various mechanisms exist that are responsible

for this interface broadening and include recoil implantation,

cascade mixing, preferential sputtering, topographical changes,

and sputter -enhanced surface segregation (and diffusion) along

point defects. The role of this last mechanism is least

understood since very little experimental data exists that shows

what effect it can have on interface widths obtained at 20 °C. A

better understanding of this type of diffusion would certainly

enhance the ability to interpret sputter dep t h -p rof i 1 e data and

thus to obtain a more quantitative characterization of surfaces

and i nterf aces .

(1) We have found that once ion bombardment (with 1-5 keV

Ar ions) of a Ni/Ag thin-film interface has produced a metastable

solid solution, Ag will segregate to the surface. This

segregation can be observed to take place after the ion

bombardment has been stopped.

(2) Our observation of the Ag segregation kinetics,

performed using Auger spectroscopy in real time at 20 °C, shows

that the Ag surface coverage exhibits a time (t) dependence

proportional to [ 1-exp ( -t/x )] , the time constant (x ) having a value of a few minutes. Such kinetic measurements, which we

believe to be unique, were done as a function of Ag concentration

and ion energy and indicate that the segregation can be

8
attributed to enhanced Ag diffusion associated with defects

produced by ion impact.

(3) The observed interface profile is dependent on the Ag

diffusion rate (which is concentration-dependent) compared to the

sputtering rate. These results clearly demonstrate that

sputter-induced diffusion can affect depth-profile measurements.

Future work will include investigation of the segregation

kinetics of a very-thin Ag film (^3-4 nm) sandwiched between two

thicker Ni films to further elucidate the point-defect diffusion

mechanism (random-walk model).

(4) Quantitative Sputter Depth-Profiling of Surfaces

(J. Fine and T. D. Andreadis)

The depth-profile analysis of ion-bombardment- induced

surface segregation of Ag at Ni/Ag interface is an example of

applications requiring special Auger techniques. Because of the

rapidly changing surface composition with time, we developed a computer -contro 1 1 ed rapid-sequential mode of Auger data

acquisition ( N ( E ) ) that acquired and stored three spectral

regions of interest (with backgrounds) in 20 seconds. Background

subtraction methods were developed to insure high accuracy,

especially for Auger lines of low energy (<75 eV).

. 3 Chemical Thermodynamics Measurements

S. Abramowitz

Chemical Thermodynamics Division

Center for Chemical Physics

(1) Variation of the Heat of Combustion of SRM Coals

with Time (D. R. Kirk 1 in)

Standard Reference Materials 1632a and 1635 are bituminous

and sub-bituminous coals, respectively. These coals are issued

by the NBS Office of Standard Reference Materials for use in

calibrating instruments and checking analytical procedures

employed in the determination of trace elements in fossil fuels.

Commercial laboratories need a sample with a known heat of

combustion to evaluate their calorimetric procedures. Since the

long term chemical stability (i.e., >1 yr . ) of powdered coals has

not been rigorously established, the certification of the heat of

combustion of coals required a study of the chemical stability of

coals.

The heats of combustion of SRM coal samples 1632a and 1635

were measured in October 1979, April 1980, June 1981, and

May 1982. Total decreases of approximately 0.88 percent and 1.51

percent were observed for SRM 1632a and SRM 1635, r e sp ec t i ve 1 y

,

over the three year period. The observed decreases are believed

to be due to the slow oxidation of coal sample upon storage under

laboratory conditions.

9
Certified heats of combustion are badly needed by commercial

testing laboratories. Since the annual decrease in the heat of

combustion of coal samples is less than the ASTM recommended

i ntr a 1 abor atory repeat ab i 1 i ty of approxi mate 1 y 0.5 percent, the

SRM coal samples can be certified. However, the certificates

must be updated annually.

(2) Sulfur, Heating Value, Ash and Moisture in SRM Coals 2682,

2683, 2684 and 2685 (D. R. Kirklin, J. C. Colbert)

During fiscal year 1982, gravimetric sulfur determinations

have been carried out for the four SRM Coals: 2682, 2683, 2684

and 2685. The coals will be certified for amounts of sulfur with

approximate values of 0.5 percent, 2.0 percent, 3.0 percent and

4.5 percent, respectively. Since combustion of the coal samples

is required for this gravimetric method, the heat of combustion

of each coal has also been determined and is being submitted as part of the report of test to the Office of Standard Reference

Materials. Measurements for moisture and ash content have also

been made.

(3) Re-evaluation of the Heat Capacity of Alumina, AI 2 O 3 (D.A.Ditmars)

Re-evaluation of the new NBS low-temperature data for

SRM 720 ( 01 -AI 2 O 3 , a heat capacity standard) were completed and

this data was incorporated along with existing NBS

high-temperature heat capacity data for this SRM into a new NBS

Certificate for SRM 720. The original experimental heat capacity

data for SRM 720 in the range 1200-2500 K which had not been

published previously (though they appeared in smoothed form in

the certificate) were included in a publication describing this

updating of the NBS SRM 720 certification.

(4) Re-evaluation of the Specific Heat of Aluminum, A1

(D. A. Ditmars)

The specific heat of aluminum(s) has been measured at NBS in

cooperation with a guest worker from Brock University, Ontario,

Canada. NBS SRM 4 4 f , a specimen of 99.9995 percent purity,

maintained by OSRM as a temperature standard (MP. 660.3 °C) for

IPTS -68 was the material investigated. The NBS data has been

analyzed. It agrees very well with published 1 ow- temper ature

heat-capacity data for aluminum. Significantly, it also agrees

much better than existing high- temperature specific data with a recently published theoretical, lattice-dynamical calculation of

the heat capacity of aluminum(s) which explicitly includes

anharmonic effects. This theoretical calculation had been

carried out for the general case of fee metals with several

assumed forms for the pair long range potential.

10
The excellent agreement obtained in this instance between

experiment and theory provides strong support for the validity of

the assumed potentials and the calculation scheme used in the fee

case. Thus, a starting point has been provided for theoretical

analysis of the h i gh -temper at ure heat capacity data of bcc metals.

Previous measurements at NBS had confirmed an unusual increase in

the heat capacity of the bcc metals molybdenum and tungsten near

their respective melting points.

(5) Evaluation of a Proposed Refuse Derived Fuel Reference

Material (E. S. Domalski and J. C. Colbert)

A synthetic refuse derived fuel (RDF) was prepared and

evaluated as a possible standard reference material for RDF. The

synthetic RDF was composed of 80% cellulose, 15% silica, and 5%

alumina. The particle size of all components was less than

50 ym. The heat of combustion, ash content, and moisture content

was measured by 12 independent laboratories which were familiar

with working with RDF. A statistical analysis of the within

laboratory repeatability and the bet ween - 1 abor at ory

reproduc i bi 1 i ty was at about the same level as observed for SRM

coal 1632a. As a result of this study, the ASTM E38.01

Subcommittee on Energy of the parent ASTM E38 Committee on

Resource Recovery concluded that the NBS prepared synthetic RDF

would make a good Standard Reference Material for RDF.

. 4 Measurement of pH

W. F. Koch and G. Marinenko

Inorganic Analytical Research Division

Center for Analytical Chemistry

The measurement of pH is one of the most common analytical

measurements performed both in the field and in laboratories

around the world. Its application cross-cuts many disciplines

including analytical chemistry, biology, medicine, material

science, and nuclear chemistry, as well as a variety of

environmental and energy projects. The concept of pH can be

described in the strictest theoretical sense; however, the

realization of the pH (the actual measurement) is possible only

in the practical sense and, at present, must be based on

qu asi -thermodynamic foundations. This in no way detracts from

the usefulness of the measurement, but it does make it highly

dependent on the standards used to define the pH scale. The

operational pH scale used in the United States and in much of the

world is defined in terms of a series of standard buffer

solutions issued and certified through the Office of Standard

Reference Materials.

In order to maintain the standards in this important area of

chemical metrology and to expand the utility and applications of

pH measurements, a new high accuracy pH/pot ent i ometry facility

has been established. Construction of the facility is complete

1

1
with the acquisition and assembly of the critical elements and

instruments. A large con tro 1 1 ed - temper at ure water bath which is

used to thermostat the pH measurement cells is operational over

the range 0 to 50 °C. The accurate measurement of the bath

temperature (±0.01 °C) is obtained through the use of a calibrated quartz thermometer. The quartz thermometer provides

the accuracy required for pH research along with the flexibility

and convenience that is unobtainable with platinum resistance

thermometers.

The emf measurements are made with a calibrated digital

voltmeter interfaced to the pH cells and to standard weston cells

through a panel of hermetically-sealed reed switches. These

switches were chosen for their low noise characteristics, low

contact resistance, and null leakage current. A digital

barometer, calibrated versus the working standard of pressure at

NBS, is used to ascertain the pressure of hydrogen gas in the pH

measurement cell.

Several configurations of si 1 ver/si 1 ver chloride reference

electrodes have been prepared for use in the hydrogen cells

without liquid junctions. These have been tested for physical

and chemical stability, r ep r odu c i b i 1 i ty , temperature coefficient

and hysteresis, all parameters critical to accurate pH

measurements. Considerable differences have been observed among

the potentials of the various types of electrodes prepared on a silver wire support is excellent (±0.05 mV). The classical

configuration using a platinum wire as the support performed less

sati sf actori ly . Additional research is needed to elucidate these

variations. Preliminary pH measurements have been made on solutions of dilute acids and of standard buffer materials.

Measurements leading to the certification of renewal SRM pH and

pD buffer materials, which are now in short supply, will commence

in FY83. Automation of the facility for routine measurements is

anticipated .

In addition, research is proposed to link the existing pH

scale directly to a fundamental physical constant, specifically

the Faraday. This will be accomplished through the use of high

accuracy coulometry to determine, on an absolute basis, the

hydrogen ion content of dilute solutions of highly purified

mineral acids. These solutions will then be systematically

compared with the primary standard buffer materials which now

serve to maintain the NBS practical pH scale. A thorough

examination of reference electrodes and liquid junction

potentials will be a necessary part of this endeavor.

Future applications of this new pH facility will include the

preparation of accurate pH standards to assure quality in

analytical measurements and the expansion of the utility of the

NBS pH scale as both a practical and a theoretical analytical

tool. An important goal of this program is to produce and

distribute pH standards which simulate the varying matrices and

ionic strengths encountered in solutions such as acidic

precipitation, body fluids, and seawater.
. 5 Isotope Dilution Mass Spectrometry in Gases

I. L. Barnes and P. A. Morales

Inorganic Analytical Research Division

Center for Analytical Chemistry

The objectives of this project are to design and construct

the instrumentation and develop the methodology for the

determination by isotope dilution mass spectrometry of the

concentrations of elements or compounds which normally occur as gases. The first application of the technique is intended to be

the determination of the concentration of CO 2 in a set of

Standard Reference Material gases.

A 12-inch radius, 90° deflection mass spectrometer for the

measurement of gases has been designed and constructed. The

instrument contains an electron impact (El) source for ionization

This source is controlled by a newly designed emission regulator

which provides an electron energy of 0-100 volts and an emission

current of 0-1000 A stable to better than 1:10^.

The instrument also has a unique triple collector adjusted

to collect ion currents at masses 44, 45, and 46, simultaneously.

The collector used a collimated beam design which, to a large

extent, removes the effects of beam scattering and stray electron

production. The measuring system employs two Cary 401

e 1 ec t rome t er s and a NBS designed amplifier. The outputs of the

amplifiers are fed to a pair of ratio digital voltmeters such

that the ratios at masses 45/44 and 46/44 are obtained directly.

The instrument is now in operation in a manual mode and

final adjustments are being made in the measurement system.

A new sample preparation and inlet system has also been

designed and constructed. The system uses a dual (sample,

standard) viscous flow inlet system and is currently designed for

twelve samples but may be easily expanded to a much larger number

The inlet system, designed for automatic, computer

controlled operation is being used in a manual mode. The

interface for computer control has just been completed and, after

testing, will be put into operation. The components for the gas

mixing system needed for isotope dilution analysis are currently

being designed with the basic vacuum system and supports

completed and in place.

During the first quarter of FY83, the system for isotope

dilution analysis should be completed and assembled. Also,

during this period the instrument and inlet system automation

should be completed, installed, and tested. During the second

quarter, the calibration of the measuring system will be

completed and applied to the measurement of the isotopic ratios

13
of a series of well defined reference materials. The initial

isotope dilution measurements will be made during the third

quarter, and during the last quarter of FY83 this measurement

technique will be applied to the set of SRM's on which isotopic

ratio measurements had been previously made.

.6 Gases in Metals

B. I. Diamondstone and J. R. Moody

Inorganic Analytical Research Division

Center for Analytical Chemistry

° Instrumentation for Gases in Metals

The large part of this year was spent evaluating the

commercial equipment that is presently available for the analysis

of gases in metals. During the first half of the year,

information was gathered and a trip was made by B. Diamondstone

to the headquarters of the Leco Corporation in St. Joseph,

Michigan.

Requests were sent out for bids in the spring and the whole

process was completed by July. The equipment was delivered and

set up by mid August. The equipment received included: (1) a furnace and determinator for the measurement of carbon and sulfur

in metals, (2) a furnace and determinator for the measurement of

nitrogen and oxygen in metals, and (3) a furnace and determinator

for the measurement of hydrogen in metals. Nearly all of the

analyses performed to date on this new equipment have been for

the determination of carbon and sulfur. Preliminary analyses

have been made on the nitrogen/oxygen and hydrogen instruments

mainly for the purpose of familiarizing the operators with the

new instrumentation and obtaining gas dosing data on both

instruments for calibration purposes.

It is anticipated that measurements on materials from a list

to be generated by OSRM and Division 551 will begin early in

FY83.

° Nitrogen in Steel

During the last quarter, work continued on this method but

was hampered by equipment failures and slow procurements . Most

of the required reagents have been received but a few, such as silicone antifoam reagents, have not yet arrived. Both the

Kjeldahl distillation apparatus, the manual titration end point

de termi n ator , and the sample digestor have been set up, repaired

as necessary, and tested. Satisfactory calibration and recovery

curves have been prepared for varying quantities of total

nitrogen .

1 4
The distillation apparatus itself was found to be so old and

fragile that after several repairs, a new unit was ordered and

has arrived. Satisfactory progress has been made in all respects

except for the bomb dissolution. These bombs have been purchased

and the next phase will involve studies on the recovery of known

materials following the dissolution of samples in the Teflon

bombs. Difficulties are expected at this point and visits to

laboratories performing routine nitrogen in steel analysis will

not take place until some experience has been gained in handling

the bombs. At that point, the laboratory visits should be of

assistance in applying all acquired skills to actual sample

analysis.

. 7 Increased Sensitivity in NAA by Background Reduction

R. L. Zeigler and J. R. Vogt

Inorganic Analytical Research Division

Center for Analytical Chemistry

The detection limits for many elements determined by neutron

activation analysis (NAA), both i nstrumental ly and radiochemically, are frequently determined by the background level of

radiation produced by other radionuclides in the sample. This

task was split into two subtasks to develop methods to further

reduce the background level of radiation using instrumental and

radiochemical techniques.

During the past year, a Compton suppression has been set up

and evaluated. In this system, the sample is inside the Nal(Tl)

anti-Compton shield, rather than outside as in some other designs.

Since there is no detection of scattered photons in the forward

direction [to the rear of the Ge(Li) detector)], the suppression

at lower spectral energies is not as good as in systems where the

Ge(Li) detector is surrounded more completely. However, the

suppression factor in the Compton edge for CS-137 is still about

8, for the middle of the spectrum about 4-5, and at the

backscatter peak about 3.5. Since the improvement in sensitivity

follows roughly the square root of the background, the increases

in sensitivity for these portions of the spectrum are

approximately 2.8, 2.1, and 1.9, respectively.

With the sample inside the Nal(Tl) shield, both coincident

photopeaks and Compton events for radionuclides with cascading

transitions are suppressed. This effect reduces the spectral

background more than simple Compton suppression. There are both

positive and negative effects from the suppression of coincident

gamma -rays. The positive aspect is that the sensitivities of

non -coi nc i dent gamma-rays are improved. This can be of benefit

in matrices where coincident gamma-rays account for a substantial

part of the activity, such as Sc-46 in environmental materials

and Na-24 in biological materials. The negative aspect is that

the sensitivity and accuracy of radionuclides having coincident

gamma-rays is reduced. There is particularly significant for

15
longer lived radionuclides for which coincident gamma-rays are

common . Overall, the system does improve the sensitivity by

activation analysis for radionuclides which do not have

coincident gamma-rays or relatively short half-lives. It should

be particularly appropriate for chromium, and investigations

involving this element are in progress.

One problem frequently encountered in the simultaneous

determination of Ag , As, Cr, Mo, Sb , and Se in biological

material using the current radiochemical separation procedure, is

the high level of background Bremsstrahl unq radiation produced by

the high-energy beta particle emitted by 32p # The inorganic

ion-exchanger HMD (hydrated manganese dioxide) used to retain the

six elements of interest also retains most or all of the

phosphorous present. Research was, therefore, directed at

developing a new procedure which would reduce to levels of 32p

retained by the HMD without affecting the behavior of the

elements of interest.

A number of different approaches were investigated including

varying the acid strength and composition of the eluting and wash

media, increasing the number of washes, addition of P holdback

carrier, use of various resin preconditioning techniques, as well

as combinations of the above techniques. Unfortunately, most

procedural changes which reduced the 32p levels also affected the

behavior of some or all of the elements of interest. However, a method was found that, with carefully controlled experimental

parameters, reduced the 32p level s by 80-90%, and had only

minimal effects on the other elements. Changes from the original

procedure include: increasing the amount (volume) of resin from

two to three ml_; decreasing the amount of Ag , As, Cr, Mo, Sb , and

Se carriers from 100 to 25 y g , preconditioning the resin with one

15 mL wash using a solution which is 1 M in both HNO 3 and H 3 PO 4

followed three or more 15 mL rinses with 1 M HNO 3 , and changing

the two 15 mL post-elution washes from a solution which is 1 M

HNO 3 , to one which is 1 M HNO 3 and 0.0025 M H 3 PO 4

. The volume of

post wash solution used is critical since often about 40-50 mL

passes through the column, large fractions of the Cr breaks

through the resin. With this new procedure, Ag , As, Mo, and Sb

were found to be quantitatively retained (>99.5%) by the resin,

and Cr and Se were nearly quantitative (>98.5%). The amount of

32p retained by the resin from Bovine Liver (SRM 1577) was

between 10 - 20 % of the amount originally present, and this

resulted in a correspond i ng reduction of background around the

5 ^Cr peak ( 320 KeV) by a factor of 5-10. In addition, the

behavior of Cd and Cu, which are frequently determined in the

combined eluted and wash solutions, were not affected (>99.5%

eluted), and could therefore still be determined following the

new procedure for Ag, As, Cr, Mo, Sb, and Se.

16
.8 High Sensitivity Measurements

J . D. Fassett, E.A.J. Michiels, H. M . Kingston

and J. W. Gramlich

Inorganic Analytical Research Division

Center for Analytical Chemistry

° Cadmium

A procedure has been developed to determine cadmium at

ultratrace levels in biological materials by isotope dilution

mass spec tromet ry . This procedure combines the use of

microchemistry with the requisite control of the analytical blank

and high sensitivity pulse counting mass spectrometry with

ionization enhancement. The procedure was used to determine Cd

in CDC bovine blood samples.

An extensive effort was made to identify and quantify all

sources of chemical bank in the procedures, where the chemical

blank arises from the dissolution and separation of the sample

and mass spectrometric loading. The table below su mm arizes the

sources of blank. An average "total system" blank of

103±53 pg (N=5) was demonstrated which would allow a 5-10%

uncertainty in Cd determinations of "normal" human blood with 0.3

to 0.6 ng/g of Cd. These total system blank measurements are

suggestive that with further experience, control of the blank

will be improved.

Determi nat i ons Range

Reagent blanks

HNOt

HC1

HC 1 0 4

HBr (ACS)

HBr(cleaned)

3

3

2

11

.6-5.3 pg/g

1.5-5. 7 pg/g

27,30 pg/gm

650 pg/g

10 pg/g

Column Blank (1.5 ml_ resin) 62 pg

Loading Blank

Total System Blanks

5 2. 2-2. 9 pg

5 65-190 pg

The yields of several alternative chemical separation

procedures using anion exchange chromatogr aphy were verified

through tracer experiments on synthetic samples and real blood

samples. A comparison of procedures using strongly basic anion

resin in the bromide and chloride forms was made. The higher

chemical blank of the bromide system discounted the increased

efficiency of separation achieved. Thus, the selected procedure

used the chloride form of the resin: a 1 mL column for the

separation of Cd from all other elements and a second very small,

0.06 mL, "clean-up" column.

17
The mass spect rometr i c loading procedure utilized a single

filament silica gel technique which provided significant

ionization enhancement. This procedure entails drying sequential

layers of silica gel, sample, and phosphoric acid and is critical

in achieving good signal intensity. The mass spectrometric

loading blank using this procedure was insignificant (2.6 pg).

Both ll^cd/lllcd and H2cd/lHcd ratios were measured which

allowed internal normalization for isotopic fractionation to be

made

.

Four CDC bovine blood samples were analyzed. About two gram

samples of blood were spiked with ^Cd and dissolved using wet

ashing oxidation. The Cd was separated and mass spectrometrically analyzed. The Cd concentration of these samples

ranged from 7.01 to 7.09 ng/g. The internal normalization

procedure improved measurement precision by a factor of three

(1.6 to 0.5%, 1 sigma) and resulted in a +5.0% correction due to

isotopic fractionation. Blank corrections were typically 5%.

The high sensitivity procedure developed should readily be

adapted to the determination of Cd in a broad range of materials.

° Vanadium

Experiments were conducted to identify the sources of blank

for both the chemical dissolution/separation procedures and the

instrumental procedures. The analytical blank resulting from the

chemistry is less than one nanogram. The primary source of the

instrumental blank is not vanadium but an isobaric interference

from the 50Q r isotope emitted from the filament material. By

washing the filaments in dilute hydrochloric acid, replacing the

normal stainless steel post with tungsten rods, and heating in a vacuum at 2000 °C for one hour, the instrumental blank can

approach the detection limits of the mass spectrometer. Having

reduced the blank significantly, the concentration of vanadium

was determined in SRM 1646, Estuarine Sediment and a Canadian

standard in which there was some disagreement as to the true

values.

Due to the low levels of vanadium in the matricies of

interest, a new low level spike (50y) was prepared at a considerably lower concentration level than previously

investigated. This spike is stable for approximately one year.

It has been calibrated by two different mass spectrometr i

c

procedures; one using a Faraday cage detection system and a second using pulse counting detection. The precision for values

using both instruments was less than 0.5 percent.

It was necessary to investigate the separation efficiency

for vanadium in biological and botanical matrices. Two

separation procedures using strong acids were investigated. The

most promising of the two procedures, using concentrated

perchloric acid, utilizes some unique properties of vanadium to

18
cause it to be quantitatively retained on a cation exchange resin.

The column geometry was found to be critical. Under optimum

conditions quantitative recoveries were obtained for both

separation procedures tested.

At the present time, both Oyster Tissue ( S R M 1566 ) and

Citrus Leaves (SRM 1572) are being prepared for mass

spec tromet r i c analysis.

. 9 Analysis of SRM 1649, Urban Du st/Organ i c s , for the

Determination of Polycyclic Aromatic Compounds

S. A. Wise, S. N. Chesler, L. R. Hi 1 pert, W. E. May,

and C. R. Vogt

Organic Analytical Research Division

Center for Analytical Chemistry

SRM 1649 , Urban Du s t /Org an i c s , which became available in

early 1982, has certified values for five polycyclic aromatic

hydrocarbons (PAH) and information values for another nine PAH.

With the availability of this large quantity (10-g units) of

homogeneous air particulate material, we anticipate interest for

PAH constituents in addition to those currently certified and

eventually for other organic constituents. As a result of this

interest, this SRM has been extensively ch ar ac ter i zed for the

determination of major and minor PAH components. In addition,

qualitative information on the polycyclic aromatic sulfur

heterocycles (PASH) and polycyclic aromatic nitrogen heterocycles

(PANH) has been obtained.

The extraction of air particulate matter with an organic

solvent provides a complex mixture of organic constituents from

which the PAH must be isolated prior to identification and

quantitation. The PAH mixtures isolated from air particulate

matter are also extremely complex because of the presence of

numerous a 1 kyl -subst i tuted PAH as well as the numerous isomeric

parent PAH. The complexity of these PAH mixtures necessitates

the use of high resolution gas and/or liquid chromatographic (GC

and LC) techniques with selective detection [ e . g . , fluorescence

and mass spectrometry (MS)] to achieve separation, identification, and quantitation of the individual components. We have

used three chromatographic approaches to characterize the PAH

mixture from SRM 1649: (1) capillary GC, (2) LC with selective

fluorescence detection, and (3) multidimensional chromatographic

techniques (i.e., normal-phase LC to isolate specific PAH

fractions followed by GC , GC/MS, and/or reversed -phase LC ) . The

first two approaches were used for the certification of selected

major PAH components in SRM 1649. The third approach has been

utilized to provide a detailed characterization of both the major

and minor PAH components in SRM 1649.

19
After isolating the PAH fraction from the air particulate

extract, the PAH mixture was fractionated using normal-phase LC on an aminosilane column as shown in figure 1. The individual

fractions were then analyzed by GC/MS and r eversed-ph ase LC for

identification and quantitation of individual compounds. The gas

chromatogr ams from the analyses of fractions 5 and 7 (see

figure 1) are shown in figures 2 and 3. These chromatograms

illustrate the complexity of the PAH mixture even after

fractionation into groups of isomers. Without preseparation by

normal-phase LC into the various fractions, it would be difficult

to identify and quantify the numerous minor components in the

mixture. Quantitation of the individual components was based on

using the PAH for which certified and information values were

available as internal standards in the various fractions.

Table 1 contains a brief summary of the numerous parent PAH and

PASH and a 1 ky 1 - sub s t i tu t ed PAH which have been identified in

SRM 1649. In addition to the PAH, the major PANH were identified

as quinoline, isoquinoline, and alkyl-substituted

quinolines / isoquinolines.

In the development of methods for the determination of PASH,

research has focused on investigation of the LC retention

character i sti cs of PASH. Reversed -phase and normal-phase LC

retention data have been obtained for approxi mate ly 50 parent and

methyl -sub st i tuted PASH. In normal-phase LC the PASH have

elution characteristics similar to the PAH, i.e., they elute

according to the number of aromatic carbon atoms. Reversed -phase

LC has been found to have excellent selectivity for the

separation of PASH isomers. Studies indicate that the

reversed-phase LC separations of PASH are influenced by the shape

of the solute as was previously found for PAH.

. 10 Methods for the Determination of Vitamins in Milk

J. M. Brown -Thomas , S. A. Margolis, L. Watts,

R . B . Wek er Organic Analytical Research Division

Center for Analytical Chemistry

The primary objective of this program is to develop new

methods and to apply established methods for the accurate

measurement of organic nutrients, including vitamins, in food

materials. Specifically, we expect to initially provide

reference or certified values for organic nutrients in a proposed

nonfat, dry milk SRM. During FY81 we examined methods for the

measurement of Vitamin D, lactose, and nicotinic acid. During

the past year, we have improved the extraction methods for

nicotinic acid and completed our work on Vitamin D and lactose.

During FY83 we anticipate completing our SRM measurements on nicotinic acid and beginning work on thiamin, lactic acid, and

p yr i do xi ne

.

20
21

Time

(min )

Figure

1.

Normal-phase

LC

separation

of

PAH

mixture

isolated

from

SRM

1649,

Urban

Dust/Organics.
FRACTION 5 yoD 8

O)

s-3

CD

a)o

toco

+-> fOo

to

c_>

a)

to

tO JCCLt

toE

S-oEo

s- <4-

LO

+Ja

<e

s- 4-O

to

•r— to>>

fOc

to

JZ

Cl

fO

i~cno

+-> <oEo

i- -Cu

to

to o

CM

<V

s_3

CD sII1111IIIiii1iii«

fl

22
FRACTION 7 i

23

Figure

3.

Gas

chromatographic

analysis

of

Fraction 7

from

normal

phase

LC

isolation

(see

figure 1

).
Table 1. Polycyclic Aromatic Compounds Identified in Washington

Urban Particulate Material (SRM 1649)

Fraction No. Compound

1 Fluorene

Methyl fluorenes (2)

a *Di benzothiophene

Methyldibenzothiophenes (3)

*C 2 -substi tuted di benzothiophenes (9)

*C 3 -substi tuted di benzothiophenes (8)

*C 4 -substi tuted di benzothiophenes

2 Phenanthrene

Anthracene

Methyl phenanthrene/anthracenes (4)

4H-Cyclopenta[def]phenanthrene

C 2 -substituted phenanthrene/anthracenes (9)

C 2 -substi tuted 4H-cyclopenta[def]phenanthrenes (3)

C 3 -substi tuted 4H-cyclopenta[def]phenanthrenes (3)

*Phenanthro[4, 5- bed] thiophene

2b Pyrene

Methyl pyrenes (2)

3 FI uoranthene

Methyl fluoranthenes

C 2 -substi tuted fluoranthenes

*Benzo[b]naphtho [2, l^d] thiophene

*Benzo[F]naphtho[U2-cr] thiophene

*Benzo[b]naphtho [2^ 3-d] thiophene

Benzo[ohi ]fl uoranthene

Benzo[^J phenanthrene

Cycl open ta[cd] pyrene

4 Benz[a]anthracene

Chrysene

Tri phenylene

Methyl chrysene/ benz [a ]anthracene/ tri phenyl enes (4)

C 2 -substi tuted chrysene/benz[ajanthracene/tri phenyl enes

Methyl bi naphthyl isomers (4)

5 Bi naphthyl isomers (3)

Benzo[b]fl uoranthene

Benzo[kJfl uoranthene

Benzo[e]pyrene

Benzo[a]pyrene

Peryl ene Methyl -substi tuted 252 MW isomers (3)

C 2 -substi tuted 252 MW isomers (2)

Benzo[ghi ] peryl ene Anthanthrene

24
Fraction No.

Table 1. (Continued)

Compound

6 Indeno[l_,2^3-cd]fluoranthene

Indenop ,2,3-ccT]pyrene

7 Di benzp, j]anthracene

Di benzp ,c]anthracene

Di benz[a , hlanthracene

Benzo[bJchrysene

Picene

8 Di benzopyrene isomers (6)

*Sulfur containing polycyclic aromatic compounds.

a

( ) indicates number of isomers present.

25
The accepted methods for the extraction of nicotinic acid

from food matrices, such as autoclaving in strong acid or base,

are harsh and lead to the formation of many undesirable products.

Therefore, we have developed a milder extraction procedure using

sulfosalacylic acid (SSA) as a protein precipitant in the

presence of hydrochloric acid. This procedure allows the

quantitative extraction of added nicotinic acid from milk samples.

However, the use of this extraction method requires the

modification of the analytical procedure to remove the highly

UV-absorbing SSA before nicotinic acid analysis. This was

achieved by using multidimensional chromatographic analysis. The

sample was applied to an octadecylsilane (ODS) reversed-phase

column which pref erent i a 1 ly retained the SSA. The nicotinic acid

was subsequently adsorbed onto an aminosilane column (connected

in series to the ODS column) and eluted with a phosphate buffer

gradient. This method allows the quantitation of nicotinic acid

in milk samples which have been supplemented with 62 yg of

nicotinic acid per gram of milk powder (containing 10 yg of

native nicotinic acid by microbiological assay). The research to

complete development of this assay procedure will include the

refinement of the chromatographi c process and development of a process for weak basic hydrolysis of the covalently bonded

nicotinamide and its conversion to nicotinic acid.

The method developed for the analysis of Vitamin D involved

the use of enzymatic (lipase) hydrolysis, HPLC separation of

Vitamins D 2 and D 3 from the milk matrix with Vitamin D 3 as the

internal standard, and a sequential HPLC procedure for final

separation and quantitation. The lipase hydroyzate was

fractionated on a cyanop ropy 1 s i 1 ane (CN) column using a 2 percent

isopropyl alcohol/hexane mobile phase. Fractionation of a milk

extract on a CN column is illustrated in figure 4. The lipase

hydrolyzate fraction is between the dashed lines. Vitamin D 2 was

separated from Vitamin D 3 and other co-extracted components by

chromatography of the Vitamin D-containing fraction by an acetonitrile mobile phase (figure 5). The D vitamins were

measured by UV detection at 267 nm. The results of the analysis

of Vitamin D 2 in a commercial milk formulation and in the SRM

candidate dry milk material are summarized in Table 2.

The lactose content of the SRM candidate dry milk material

was measured by HPLC utilizing a carbohydrate column. The

lactose was eluted with 80 percent acetonitrile/water and

measured with a refraction index detector (figure 6 ). By use of

an external standard, the lactose content was found to be

4 4± 1 percent (g/g) in the candidate SRM and 34±1 percent (g/g) in

a commercial milk sample.

26
I

I

I

1

Figure 4. Fractionation of a milk extract

on a CN column.

Figure 6 .

Analysis of a milk fraction for Vitamin D2 on a reversed-phase column.

O

(AO

u

O

Analysis of lactose in

a mi 1 k sample on a reversed-phase column.

27
Table 2

.

Concentration of Vitamin D 2 in Dry Milk

Samp 1 e D ? (ng/q milk ±SD)

C ommerc i a 1 Fortified Mat er i a 1 -Box 1 83 ± 3^

C ommerc i a 1 Fortified Materi al -Box 2 0 1+ 3

C ommerc i a 1 Fortified Mat er i a 1 -Box 3 95

Unfortified SRM candidate <10

^ Values represent standard deviation of a single measurement.

. 1 1 Development of an Isotope Dilution/Mass Spectrometr i

c

Definitive Method for the Determination of Serum Urea

A. Cohen, H . S. Hertz, R. Schaffer, L. T. Sniegoski,

M. J. Welch, E. White, V, W. T. Yap

Organic Analytical Research Division

Center for Analytical Chemistry

Definitive methods provide the clinical chemistry community

with an accuracy base to which reference, and ultimately, field

methods can be compared. We have been involved for several years

in the development of definitive methods for organic serum

analytes and have successfully developed such methods for

cholesterol, glucose, and uric acid. Another clinically

important analyte in serum urea, which is used as a measure of

kidney function and in protein metabolism studies. Work has now

been completed on a method for serum urea which is of sufficient

accuracy and precision to be considered a definitive method.

This method utilizes isotope dilution mass spectrometry, as have all of the other definitive methods for organic serum

analytes. A brief description of the method is as follows: A

weighed quantity of urea-^O is added to a known weight of serum

such that the labeled/unlabeled urea ratio is near 1:1. After an equilibration period, the sample is freeze-dried and the urea is

extracted from the residue and sublimed. The sublimate is added

to a mixture of diketene and glacial acetic acid in a vial, which

is then sealed and heated at 82-82 °C for two days. Under these

conditions urea is converted in high yield to 6-methyl uraci 1

.

After the solvent and unreacted diketene are evaporated, bis(tri

met hy 1 s i 1 y 1 ) ac e t ami d e is added to convert the product to

6-methyluracil-diTMS. Calibration standards, consisting of known

amounts of the labeled urea-^0 and pure Standard Reference

Material (SRM) 912, Urea, are also converted to the derivative.

For each sample, the two standards, whose u n 1 abe 1 ed / 1 abe 1 ed

28
weight ratios most closely bracket that of the sample, are

selected. The sample and its two standards are injected onto a 30-meter SE-30 SCOT gas chromatographic column operated at 125 °C

in the following sequence: One standard is injected, followed

5-1/2 minutes later by the sample and 11 minutes later by the

other standard. After a 25 minute retention time, the ion

abundance ratios for the ( M-15

)

+ ions at m/z 255 (unlabeled) and

257 (labeled) are measured for each of the three peaks.

Measurements are made in the electron impact (El) mode at 70 eV,

utilizing magnetic field switching. The ratio from the sample is

compared, using linear interpolation, with the ion abundance

ratios from the standards to find the quantity of unlabeled urea

in the sample. For each sample, measurements are reported, on a second day with the order of standards reversed, and the mean of

the two days' measurements is taken as the reported result.

Because of contributions of the labeled urea derivative at

the mass monitored for the unlabeled derivative, and vice versa,

the relationship between weight ratios and ion abundance ratios

is not truly linear. A mathematical study was performed to find

the maximum error possible when linear interpolation was used

with our bracketing standards. The worst case, which occurs when

the ratios of the two standards are the farthest apart and the

bracketed sample falls midway between the two, was found to be

less than 0.04 percent for our standards. Thus, linear

interpolation can be used without correction. A description of

this mathematical study has been submitted for publication in

Biomedical Mass Spectrometry .

The method was used to measure urea levels in both

freeze-dried and frozen serum pools. Three sets of samples were

prepared from SRM 909, a freeze-dried human serum pool. Each set

consisted of two samples from each of three vials of SRM 909.

The results are summarized in Table 3, including the overall mean

value which is the certified concentration for the SRM. As a test for hidden i n terf erences in the above measurement

conditions, two samples from each set were remeasured using

different pairs of ions; first, El measurements of the (M-30) ++

ions at m/z 120 and 121, and second, chemical ionization (Cl)

measurements of the (M+l) + ions at m/z 271 and 273. These

results, along with the previous results for those six samples,

are shown in Table 4.

The urea level was also measured in five frozen serum pools

from a Centers for Disease Control round robin study. Three

sets, each consisting of one sample per pool, were independently

prepared. The results are shown in Table 5.

One sample from each pool was remeasured using the alternate

ions. The mean differences from the results for the 255/257 ions

were +0.03 percent for the 120/121 ions nad +0.01 percent for the

271/273 ions. These pools were also analyzed at CDC by the

coup 1 ed -en zyme candidate reference method. Their results for the

five pools differed from our results by -0.58 percent to +1.15

29
percent, differences which are small compared with the

imprecision of their measurements, thus providing strong evidence

that no serious systematic bias exists between the two methods.

For a method to be considered definitive, the results must

be free of significant bias and be of high precision. This ID/MS

method for urea has provided high precision results for both

freeze-dried and frozen serum. Confirmatory measurements at

alternate ions demonstrate that no significant biases exist among

the three measurement conditions. Thus, the probability of a hidden interference is very small, since such an interference, to

remain undetected, would have to co-elute with the 6-methyluracil-diTMS and contribute proportionally the same at the three

ions measured. No other source of significant bias has been

found, therefore, the requirements for a definitive method have

been satisfied. A manuscript describing the method is in

preparation.

Development of definitive methods for creatinine and

triglycerides is in progress and a method for digoxin is in the

planning stage. Each method developed will be used to certify

the concentration of the corresponding analyte in the Human Serum

SR M.
Table 3. Urea Levels Found in the Human Serum SRM by the

ID/MS Definitive Method (6 sample per set)

Mean CV

Set mg urea/g serum pellets %

1 7.236 0.07

2 7.249 0.17

3 7.247 0.06

Statistical Summary: Mean = 7.244; CV's - replicates 0.14%,

sets 0.10%, reproducibility 0.17%. Standard error of

average = .00439, C V = 0.06%.

Table 4. Urea Levels Found in Si x Human Serum SRM Samples Using

Three Different Pairs of Ions

Mean CV % Difference from

Ions Measured mg urea/g serum pellets % (255/257) Results

255/257 7.242 0.12

120/121 7.239 0.12 -0.05

271/273 7.240 0.12 -0.03

Table 5. Urea Levels Found in Five Round Robin Frozen Serum

Pools by the ID/MS Definitive Method

Mean CV

Pool mg urea/g serum %

Control 1 . 2393 0. 13

Contro 1 2 . 8828 0 . 14

Unknown 7 1.525 0.23

Unknown 8 . 3564 0. 13

Unknown 9 .8259 0.15

31
. 1 2 Improved Instrumentation for Organic Isotope Dilution/Mass

Spectrometry Measurements

S. Meiselman, F. Ruegg, R. Shideler, M. J. Welch,

and E . White, V Organic Research Analytical Division

Center for Analytical Chemistry

Our ongoing project to develop definitive methods for

organic serum analytes requires instrumentation of high stability

to provide the necessary precision. All of our work to date has

been with serum analytes present in relatively high concentrations. As future work turns to analytes in lower concentration,

our instrumentation must be even more stable than before, if we

are to continue successful development of definitive methods.

Our approach to improved instrument stability has been to seek to

upgrade existing instrumentation, rather than to purchase costly,

new systems. In recent years, upgrades have included replacement

of the mass spectrometer source diffusion pump with a turbomolecular pump for reduction of pressure fluctuations, installation of a pressure regulated flow system in the gas

chromatograph, installation of a variable splitter at the head of

GC column, and the use of fused silica tubing for the transfer

line in the GC/MS interface.

Recently, we have replaced both the multiple ion monitoring

system and our old data handling system with a new system

assembled principally from components available in the NBS

storeroom. The new system, diagrammed in figure 7, is designed

to provide computer control for certain instrument parameters

which have to be rapidly and reproducibly changed, as well as to

handle data acquisition and reduction. A 64 K mi crocompu ter

controls switching of the magnetic field for each measurement

cycle, through a 16 bit d i g i t a 1 -an al og converter (DAC). After

each switch of the magnetic field, the computer waits for a signal indicating that the field has stabilized before generating

a triangular „aveform through a ±150 volt power supply. This

waveform, whose frequency and amplitude are computer controlled,

is sent to the mass spectrometer detector beam deflection plates

a preset integral number of times for each measurement cycle.

This provides for more reproducible data acquisition than

achieved with the old system in which the waveform was generated

continuously and the measurement began at random points across

the waveform. The ion intensity signal generated by the electron

multiplier is fed through a solid state preamplifier, built at

NBS, which provides better stability and linearity of response

than the vacuum tube device which came with the mass spectrometer.

The signal, after passing through the original amplifier for the

mass spectrometer, is digitized by an analog-digital convertor

(ADC). The computer generates two real-time displays of the

data; numerical data is shown on a CRT, and an analog signal is

32
I

o

c

o> in

Lf) c

0) cc

o

33

Figure

7.

Diagram

of

the

upgraded

organic

isotope

dilution

mass

spectrometer

system.

*New

components.
sent to a strip chart recorder for display of the ion

chromatograms for the unlabeled and labeled species. After data

acquisition is complete for each sample, the computer corrects

the accumulated data for baselines measured before the elution of

the analyte and calculates the ratio of the corrected ion

abundances of the labeled and unlabeled species. The ratios are

displayed on the CRT and the accumulated counts and ratios are

fed to a printer for permanent record. The computer is

interfaced to a dual disc drive for access to operating programs,

and parameter files for each analyte.

The new system exhibits improved precision and greater

reliability, enabling us to measure serum urea levels with an overall relative precision of 0.17 percent, compared with 0. 2-0.4

percent overall precisions for cholesterol and glucose with the

old system. The computer provides the capability of controlling

other instrumental parameters and modifying our data acquisition

and reduction as necessary.

Our most recent system upgrade has been installation of an NBS-built circuit to control the ion source temperature in the

mass spectrometer. Previously, the ion source temperature

changed while measurements were being made and corrections were

through manual adjustments in the heater current. The new

circuit senses the temperature in the source and adjusts the

heater current appropriately. This improvement simplifies the

operator's task and we also expect it to make ion source

conditions more stable, leading to better precision.

Plans for further improvements include acquisition of an electron-impact-only ion source for the instrument to use in

conjunction with our combined e 1 ectron -i mpact chemicalionization source. Such a source, optimized for one mode of

ionization, is expected to provide more stable operation in that

mode than is possible with the combination source. We also plan

to test a new ion selection method in which the magnetic field is

held constant and the ion beam is switched at the deflection

plates. Such a system should allow for less delay time between

measurement cycles since magnetic hysteresis effects, which now

limit the switching rate, will be avoided. The major effort

required for this new technique is the generation of the

necessary software for the existing system.

.13 Surface Reactions of Gas Mixtures

Walter L. Zielinski

Gas and Particulate Science Division

Center for Analytical Chemistry

One of the most perplexing, time-consuming, and costly

phenomenon encountered in the development of gas cylinder

mixtures for SRM certification is that of gas instability. This

is observed analytically by decreases in the concentration of the

34
certifiable gas specie over a period of time. Instability is

most often encountered in cylinders containing reactive gas

species (NO, NO 2 SO 2 , CO), and is believed to be primarily due to

reactions occurring at the surface of cylinder walls and valves.

Such reactions may be catalyzed by metal oxides, traces of water,

hydroc arbons , and trace gas impurities. The objective of this

research is to characterize the chemical nature of unstable gas

mixtures in order that gas standards instability may be better

understood, and minimized or eliminated. The research approach

taken is aimed at the identification and measurement of the

differences in principal and trace gas phase constituents between

stable and unstable gas cylinder mixtures, as well as assessing

species adsorbed by the cylinder wall surface.

(1) Gas Phas Studies of NO in N 2 Cylinder Mixtures

(B. C. Cadoff)

Decreases in the concentration of NO in N 2 gas cylinder

mixtures with time have occasionally been noted, resulting in the

rejection of such cylinders as SRM's. The decrease in NO over a several month period can be as high as 2 % or more, the explicit

cause of which is unknown. An analytical investigation was

undertaken of stable and unstable NO in N 2 cylinders taken from

three cylinder batches (nominal concentrations: 100, 500 and

1000 ppm). While it was recognized that these cylinders were

prepared commercially, it was felt that they would represent a useful preliminary model for analytical studies.

In order to ascertain trace gas species which were

potentially relevant to observed NO concentration decreases,

homogeneous gas phase reactions were considered that could occur

in the cyl i nder

:

2 NO hh O 2 " • ") 2 NO 2 ( 1 )

2 NO 2

^Tr""> N 2 O 4 ( 2 )

NO hh NO 2 - /

N

2 O 3 (3)

3 no 2 + H 2 O ^=*2HN03 + NO (4)

NO + no 2 + H 2 0^=72HN02 (5)

Equilibrium and rate constants are either known or can be

calculated for these reactions. These constants were used in a CCP kinetics computer program that yields concentrations of

products as a function of time for selected starting

concentrations of NO, NO 2 , O 2 and H 2 O. Preliminary modeling for

the 100 ppm NO case verified that:

0 Oxygen, if present initially, would be rapidly consumed

(several hours) due to the rapid rate of reaction ( 1 ).

3F
° The only significant reactions resulting in loss of NO

are reactions (1) and (5).

° Time -scale changes in NO concentration are in the order

of several months to a few years, depending on the

initial concentration of the other species present

(H 2 0, 0 2 , N0 2 ).

One important observation of the modeling was that HN0 2 is

produced as a principal end-product of NO gas phase chemistry

(reaction (5)). Excluding significant cylinder wall surface

effects, analysis of HN0 2 might infer whether or not, and to what

extent, the reactions in the cylinder are homogeneous gas phase.

Preliminary analyses to ascertain the presence of HN0 2 , run

using Four i er-transf orm IR spectroscopy (FTIR) using a 20 cm IR

cell, were inconclusive. A long-path "white" cell (effective

pathlength, 110 m) is now being put into service, which should

provide the required sensitivity for this analysis. This cell

will be used to assess the presence of other products (e.g., N0 2 ) and trace impurities. Direct inlet high-resolution mass

spectrometry revealed a higher m/e 52 line in unstable NO

mixtures. Preliminary data indicated the species as cyanogen;

this will be reexamined using the FTIR white cell.

Reaction (5) also pointed out the need for accurate and

precise analytical methods for trace N0 2 and H 2

. Table 6

presents data for H 2 0 and NO concentrations for six cylinders.

Data collection of trace species has been underway and will

continue over the next several months. Sufficient data are

needed before meaningful conclusions can be drawn regarding NO

stability. Improved methodology for trace levels of N0 2 and H 2 0

in the presence of NO is currently being evaluated.

Future investigations should consider analytical studies of

the chemistry of NO in N 2 mixtures in which we condition and fill

cylinders with known starting materials and analyze the relevant

trace species over time. Such experiments should yield an improved control of the experimental design and allow further

examination of cylinder surface effects on gas instability.

36
Table 6. Analytical Data for Selected NO Cylinders

Cylinder Identification Nominal NO Analyzed NO Cone. Analyzed H 2 0

Cone (ppm) (ppm) Cone (ppm)

41-4-C 1000 955 (2/80) 12.0 (9/82)

920 (12/81)

41-2-C 1000 955 (2/80) 6.1 (9/82)

955 (12/81)

42-32-C 500 472 (12/80) 8.3 (9/82)

454 (8/81

)

42-15-G 500 471 (12/80) 10.5 (9.82)

471 (8/81

)

44-68-G 100 93.1 (5/81) 30.0 (9/82)

92.6 (11/81)

44-98-G 100 93.1 (5/81) 16.5 (9/82)

93.1 (11/81)

37
(2) Surface Absorption of Trace Water in SO 2 in N 2 Cylinder

Mixtures (G. Sleater)

Several cylinders having SO 2 concentrations significantly

lower than the batch average were selected from batches of SO 2 in

N 2

. It was proposed that the level of moisture in the cylinders

might influence loss of SO 2

. Consequently, water vapor content

of these cylinders was studied as a function of cylinder pressure

and cylinder temperature.

Initial water analysis (coulometric trace moisture analyzer)

revealed that cylinders that were lowest in SO 2 contained about

twice the water level (50-100 ppm) compared to cylinders having

an SO 2 concentration similar to that of the batch standards. As

the cylinder pressure was progressively decreased from an initial

pressure of 1500 psi or more, to below 200 psi , the water content

showed an initial marked increase followed by a rapid decrease.

Water levels decreased as the cylinder pressure was lowered to

about 500 psi, following which, a slight increase in water was

noted. The increases in water concentration were attributed to

desorption of moisture from the cylinder walls as the cylinder

pressure decreased .

To test the degree to which water vapor increases because of

desorption from the cylinder wall, cylinders were immersed in a 55 °C water bath for 30 minutes. The water vapor concentration

increased from 62 to 115 ppm following cylinder heating, while

the NDIR ( non -d i spers i ve infrared) analysis signal for SO 2 was

unchanged. The use of a drying trap prior to the moisture

analyzer decreased the trace water vapor content, but did not

affect the NDIR measurement of SO 2

. Measurement of water vapor

as a function of time after cylinder heating showed that cylinder

surface absorption of water vapor re-occurred (Figure 8).

Packing a cylinder in ice resulted in a decrease in water vapor

concentration due to increased cylinder surface absorption. The

ice-packed cylinder decreased in water vapor concentration from

85 to 61 ppm, and increased to 67 ppm 3.5 hours after removal

from the ice bath

.

From these studies, it was confirmed that: (1) water vapor

content is generally greater in batch cylinders which have

diminished SO 2 levels relative to the batch standard, indicating

a possible effect of trace water level on SO 2 loss; (2) water

vapor increases as cylinder pressure is decreased (or as cylinder

temperature is increased), due to desorption of water from the

cylinder wall surface; and (3), that an increase in water vapor

does not evidence any immediate effect on the lowering of the

observed SO 2 concentration in the cylinder. Further experiments

are necessary to determine whether an increase in the

concentration of water vapor will have long term effects on SO 2

concentration, and hence, on SO 2 concentration stability.

38
Figure 8. Decreases in cylinder water vapor (ppm) due to

surface resorption as a function of time (minutes)

after cylinder heating to 55 °C.

39
• l 4 XRD Crystallite Size

C. R. Hubbard and A. L. Dragoo

Materials Chemistry Division

Center for Materials Science

Characteri zation of the mean crystallite size in the range

100 to 1000 A can be done rapidly and nondest rue t i ve 1 y by x-ray

powder diffraction (XRD). Crystallite size is difficult to

measure by SEM due to agglomeration. Knowledge of the

crystallite size is important in understanding sintering of some

speciality ceramics. Crystallite size is often useful in rapidly

assessing the reactivity of a heterogeneous catalyst. To date,

no calibration standards are available for instrument calibration

or procedure testing. Because of dependence on instrumental

effects and the complexity of the analysis procedure, results

from different laboratories are not comparable. Development of

an XRD Crystallite Size SRM will alleviate this problem.

MgO has been chosen as a crystallite size standard, with two

or t h £ e e SRM's to be prepared with sizes ranging from 100 to

1000 A. Mi crocrys tal s with excellent habit are being formed from

an MgO smoke and collected with an electrostatic precipitator.

The size of these mi crocrystal s will be measured with an SEM and

then used to calibrate the diffraction measurements. Bulk

quantities of MgO are being prepared by calcination of basic

magnesium carbonate.

The stability to the atmosphere (H 2 O, CO 2 , etc.) has been

checked by two different tests. In the first, a sample was

mounted for diffraction measurements, left in the laboratory air,

and XRD data collected six times over a period of nearly 700

hours. The mean crystallite size in the (200) direction remained

essentially constant, while in the (111) direction, the mean size

dropped in the first few hours and then stabilized. The

integrated intensity of the (200), (400), (111), and (222) lines

followed this same rapid drop and then stabilization. A second

sample mount was exposed to a high humidity environment

(saturated air at 60 °C). Again, the (111) direction showed a quick drop in mean crystallite size, while the mean size in the

(200) direction was stable. Integrated intensities also showed

an initial decrease and then constant value. No second phase

diffraction (e.g., MgOH) lines have been found in either mount.

Changing the calcination temperature is expected to increase

the mean crystallite size. Two methods of measuring the mean

crystallite size were employed to evaluate the effects of

calcination temperature on the mean crystallite size. Using the

Warren-Averbach method, we obtained a change in crystallite size

in the (200) direction from 116 to 246 A, corresponding to 600

and 900 °C. Using the Stokes integral breadth method, a somewhat

larger crystallite size was determined for the samples prepared

40
at higher temperature. This likely indicates an increase in

strain in the crystallites prepared at higher temperature.

. 15 Chemical Spec i at i on/B i ode t er i or at i o n of SRM's

G. J. Olson, W. P. Iverson, and F. E. Brinckman

Materials Chemistry Division

Center for Materials Science

With OSRM support we developed and applied metal speciation

techniques to analyze several SRM's (shale oil, freeze-dried

urine, oyster tissue, bovine liver) for levels of certain metal

species, with the goal of providing OSRM with molecular

composition of an SRM in terms of selected elements. Increased

requests for information on our work from Government, industrial,

and academic scientists around the world reflect growing recognition of the importance of, and prospects for, determining trace

metal-containing molecular entities in biological materials. Our

work includes the first metal speciation study of a clinical

standard, and will greatly assist OSRM in meeting growing needs

for related new biological standards. We have also examined

several new SRM's (freeze-dried urine, bovine liver, citrus

leaves) for sterility and developed a new b i odeter i or at i on

screening technique for OSRM which allows a rapid diagnosis in

cases where an SRM is suspected to be contaminated.

In last year's report we described development and

preliminary applications of a new ultratrace analytical method

employing a tin-specific flame photometric detector (FPD)

automatically coupled to a purge and trap gas chromatograph

(P/T-GC). We have concluded an evaluation of this technique for

speciation and quantitation of a heavy metal in a clinical SRM

being re-released by the NBS Office of Standard Reference

Materials as (new) Freeze-Dried Urine.

In the urine SRM's, volatile sulfur compounds are detected

in both S- and Sn-electrive modes; involatile ionic tin compounds

require borohydride reduction for their volatilization as stannanes into the GC system and are detected only in the Sn mode.

Some of the major species identified include (CH 3 ) 2 SnH 2 and

(CH 3 ) 2^2- A monobutyltin species, C 4 HgSn 3 +

s (determined as

C 4 HgSnH 3 ) appears in the same chromatogram. Quantitative results

are summarized in Table 7.

There are both qualitative and quantitative differences

between the two SRM's, doubtless reflecting different polled

sources. Detection of a butyltin species in both materials is a notable finding since there are no known biological butylation

reactions comparable to b i omet hy 1 at i on . These results may

indicate human exposure to increased worldwide industrial use of

butyl tins, at least in the SRM source population. As a wide

spectrum of organotins find greater use in manufacturing and

biocides, methods and standards for health monitoring and

41
Table 7. Concentrations3 of Tin and Sulfur Species in Previous and

Mew MBS Freeze-Dried Urine SRM's

Species "Old" SRM "New" SRM

(CH

3

)Sn

3+

1.0 ND

(CH

3

) 2

Sn

2+

ND 0.46

C4

H

g

Sn

3+

1.5 0.03

Inorganic Sn(II) or Sn(IV) 23.1 ND

(

C

H

3 > 2

S

2

MD 2.73

By method of additions: in yg/L; ND = not detected.

N3S SHALE OIL SRM 1580

EXP=2

Li » i ll 11. 1. >- . 1 1 . >

AA

UV

AA

I 1 1 1 1 0 10 20 30 40

ML

Figure 9. Dual -element SEC-GFAA chromatograms specific for As and Fe are compared for the MBS Shale Oil SRM in tetrahydrofuran. The maximum

absorptivity in the tandem UV trace indicates the heavy organic

loading of the oil. Co-elution of As with Fe at 22 mL suggests

common macromolecular carriers with molecular weights of ca. 2500.

Post-column addition of Ni(II) enhanced the As signal and insured

equivalent As response throughout the elution.

42
occupational exposure are needed. The SRM speciation methods now

demonstrated can greatly assist in meeting these measurement

requ i rement s

.

Another important measurement development for standards

involves our continuing use of HPLC coupled with graphite furnace

atomic absorption spectrophotometric (GFAA) detectors for element

speciation. During the past year, we devised means to improve

sensitivity with automated post-column der i v at i zat i on for

HPLC-GFAA, so that little or no modification of the established

chromatographic separations would be required. Part of our goal

was achieved with a new mixing device that simultaneously

receives regulated flows of HPLC effluent and various dilute

transition metal salt "enhancer" solutions prior to transport

into the GFAA detector. Thereby, the active surface of the GFAA

cuvette is continually refreshed with enhancer to yield more

reproducible atomizations with sensitivity increases up to

50-fold. This improved GFAA method was used to characterize As

in the shale oil SRM.

For molecular characterization of arsenic in shale oil by

size exclusion c hromatogr aphy (SEC), a huge excess of

carbonaceous residue must be charred before GFAA atomization. At

the required temperatures over 1000 °C, many arsenic compounds or

their decomposition products volatilize and would not be detected.

In this case, addition of nickel(II) solutions to the SEC-HPLC

system gave optimum signal enhancement for both small, volatile

molecules such as dimethylarsenic acid and As-containing

macromo 1 ecu 1 ar components of shales. OSRM has supported our

efforts to evaluate NBS SRM 1580 Shale Oil as a suitable matrix

for speciating arsenic. Arsenic concentration in this material

(which has been certified only for selected organic compounds)

has been determined by GFAA to be 2 ±0.03 ppm. Using SEC-GFAA

procedures noted above, we have successfully determined As

content of SRM 1580 as a function of molecular weight in the

range from 100 to 20,000. The arsenic eluted at retention

volumes corresponding to 1500 to 2000 Daltons as depicted in

figure 9. By using gradient anion exchange GFAA chromatographic

methods developed in our group, we have isolated both methyl and

phenylarsenic acid in source Green River formation shale oil of

the type used for SRM 1580. Their presence, now confirmed

co 1 1 abor at i ve 1 y with Dr. R. H. Fish of Lawrence Berkeley

Laboratory by derivatization GC-MS, illustrates for the first

time unequivocal independent evidence for true organo metals in a major fossil fuel source matrix.

Installation of an epifluorescence microscope facility in

the Group's laboratories enabled us to develop new, rapid methods

to examine microbial attack on SRM's. The b i od et er i or at i on of

SRM's, especially those based on naturally-occurring matrices for

clinical and environmental users, was rapidly assessed using

fluorescent dyes to detect microbial growth in contaminated

liquid (urine) and solid (oyster tissue, orchard leaves) SRM's.

Such methods can be used by OSRM and its customers to quickly

43
examine SRM's suspected of being microbially contaminated without

costly microbial culture media, sterilization and incubation

facilities.

. 16 Research on Dye Penetrant Microhardness and Thickness SRM's

D. S. Lashmore

Materials Chemistry Division

Center for Materials Science

(1) Dye penetrant crack SRM's have been in production for two

years and last year more than 100 were made. This SRM is

fabricated using electro-forming technology and consists of

alternative layers of copper and nickel. There are four layers

of copper: the thickest is nominally 2 ym, then next 1 ym,

followed by 0.5 ym and 0.2 ym. These copper layers are then

electrochemi cal ly removed and the space that the copper occupied

constitutes the crack. A research project was undertaken to

improve various unsatisfactory manufacturing techniques and to

investigate several important aspects of the crack geometry that

have a bearing on dye pick-up and apparent crack width. Among

the topics that were examined were (a) the extent to which the

crack edge was "rounded" and by the etching procedure; (b) the

depth to which the crack penetrated into the block; (c) the

polishing technique which was known to "smear" the nickel over

the copper; and (d) various techniques to automate the production

process. In order to eliminate as much as possible the rounding

of the crack, an improved etching technique was developed and the

polishing procedure was change to reduce to the maximum extent

possible the smearing of the nickel. The depth of the crack was

also measured. This project is quite important as the Federal

Aviation Agency is mandating the use of our dye penetrant crack

blocks for use in the inspection of commercial aviation (wing

spars, landing gears, etc.). We anticipate producing from 300 to

500 of these standards next year.

(2) In response to a request from the Offices of Standard

Reference Materials and Nondestructive Evaluation, we have

developed two new microhardness Standard Reference Materials, one

of 100 kg/mm? and another about 500 kg/mm^. The ma in problems

with the standards now available from the makers of the

microhardness instruments are typically (a) the lack of

uniformity of hardness across the surface, and (b) the lack of a certified hardness. The hardness non-uniformity is a result of

inhomogeneities in cooling rate and the resultant composition,

inhomogeneity, and grain size variation. Electrodeposition

technology allows almost an atomic control of structure and

composition. We have succeeded in fabricating hardness SRM's of

significantly improved hardness uniformity. These will be made

available through the Office of Standard Reference Materials some

time next year. Research in this area is continuing to extend

the range of hardness to over 1000 kg/mm^ so that a complete set

of standards will be available. We have had a number of requests

44
from industry for Rockwell hardness standards which we will be

eval uat i ng next year

.

(3) Improved software involving a more accurate nonlinear least

squares fitting procedure was implemented as were improved

operating procedures for the x-ray fluorescence apparatus itself.

Using these new improvements in our measurement technology, we

have been able to fabricate a number of very thin, gold SRM's

(0.13 ym and 0.25 pm) which will be made available to the public

through OSRM.

Improved plating procedures for the gold deposition now

allows all plating to be done "in-house" resulting in improved

coating quality and rapid response to requests for new SRM's.

The x-ray fluorescence apparatus has been directly connected

to our S-100 computer to enable almost real-time data reduction.

This procedure eliminates the old teletypewriter which was used

to store the data on punched tape and then used to read the tape

over a phone modem to a large mainframe computer which eventually

returned the reduced data to the teletype. The old system was

not only very costly but more importantly was quite unreliable.

. 17 Glass Standard Reference Materials

M . C e 1 1 a r o s i Materials Chemistry Division

Center for Materials Science

(1) Dielectric Constant SRM

Certification of SRM 774 for Dielectric Constant and related

Loss Character i st i cs was accomplished this year.

Development of this standard and improved methodology was

carried out in collaboration with ASTM Committee C14 on Glass

Properties and industrial laboratories, principally to resolve

serious measurement errors that existed in industry. SRM 774 now

on sale, will provide support to the expanding role of glass in

electrical/electronic applications. The standard will also help

in energy conservation efforts (e.g., low loss insulators and

dielectrics), and in the evaluation of other materials properties

such as dielectric breakdown, moisture content, deterioration,

etc .

(2) Glass High Temperature Resistivity SRM

In cooperation with ASTM Committee C14 on Glass Properties

and the glass industry work is in progress to develop this

standard and related measurement methods. This project was

undertaken in response to a priority listing generated by

i n d u s t r y

.

45
Glass resistivities as a function of temperature in the

molten range are important parameters for effective utilization

of electric power, productivity, quality, and for reduction of

air pollution from furnaces. Resistivity data is also important

in the design of melt/process equipment. This SRM will benefit

primarily the glass industry as melting operations are modernized

and converted to electrical power.

NBS leads the ASTM task force to develop the SRM and

standard methods. Procedures and samples (SRM 711, Viscosity

Standard) have been distributed. Interlab comparisons now in

progress utilize high temperature viscometry methods for the

generation of simultaneous res i st i vi ty/vi scos i ty data.

Calibrations and study of techiques are in progress at NBS.

(3) Glass Viscosity SRM

A new improved high temperature viscometer is being

constructed in anticipation of replacing viscosity SRM 710

(soda-lime-silica glass). This viscometer utilizes a commercially available torque measuring system and a furnace

designed at NBS. Furnace construction and refinement of

mechanical details are planned to allow ample time for

calibration prior to SRM certification.

. 18 Catalyst Package for Lubricant Oxidation Tests

C. S. Ku

Materials Chemistry Division

Center for Materials Science

Lubricants in service encounter a chemically harsh

environment. Combustion gases carrying partially oxidized fuel

components have been identified as the key chemical species that

control the degradation pathway of the lubricants. Realistic

simulation of the engine environment requires the synthesis of

the reactive species in the combustion gases.

A procedure to synthesize these species has been developed.

This material when used in laboratory bench tests simulates the

critical chemical reaction pathway which exists in an operating

engine, and enables significant correlation to be obtained

between bench tests and engine tests.

A high boiling fraction (>150 °C) of a gasoline is oxidized

in the presence of 2000 ppm nitrogen dioxide at 125 °C for 72

hours. The oxidation is terminated when the total acid number

(TAN) of the o x i d i zed / n i t r at ed fuel components reaches about 15.

The fuel components are then neutralized with saturated sodium

bicarbonate solution to a TAN of about 2. The neutralized

product is used as the oxidized/nitrated fuel fraction.

46
The oxidized/nitrated fuel fraction can be used with a soluble metal naphthenate mixture ( Pb/Fe/Cu/Mn/Sn

:

82%/7%/4%/3 . 5 % / 3 . 5% ) . These metals have been found in used oil

analyses to test automotive engine lubricants. The NBS thin-film

oxidation test uses five percent of each of the oxidized fuel

fractions and metal mixtures in evaluating the oxidation

stability of automotive crankcase lubricants. The test measures

the oxidation induction times of the test lubricants. Test data

on ASTM 1 1 1 D engine test stand reference oils are compared with

those with no fuel and metal catalysts in Table 8. The data

indicates that the use of the fuel components and metal catalysts

significantly changes the relative oxidation stabilities of the

reference oils. A batch apparatus has been set up for the fuel

oxidation. This temperature controlled apparatus is a scaled up

version of an earlier operation. A five liter three-neck glass

flask is used as the reactor to replace test tube operation

('vlOQ mL) previously used. Air is bubbled into the fuel fraction

and is mixed up with the fuel by an air-driven stirrer to ensure

uniform oxidation. The oxidation temperature is measured by

thermal couplers connected to the temperature controller. If the

temperature of the fuel fraction becomes higher than the

pr edetermi ned safety set point, the controller will shut off the

air supply and the power.

With this scaled up version of the fuel catalyst

preparation, we are now in a position to produce sufficient

quantities of the catalyst for SRM production.

. 19 Self -Cal i brat i ng Gel Permeation Chromatography

I . C . Sanchez

Polymer Science and Standards Division

Center for Materials Science

Gel permeating chromatography is a widely accepted technique

for estimating the molecular weight distribution (MWD) of high

polymers. However, the usefulness of the conventional GPC

apparatus is limited by the need to provide calibrants for each

polymer measured of known molecular weight over the entire

molecular weight range in which the MWD is significantly

different from zero. The calibration depends, among other

things, upon the chemical nature, degree of branching, etc., of

the polymeric material so that each new material requires a fresh

calibration. The so-called "universal calibration" hypothesis,

while useful, is limited to comparisons of polymers of similar

shape and, in any event, is inadequate for quantitative

determinations. Some instruments, one of which is commercially

available, attempt to circumvent the need for calibrants by

adding a single-angle light scattering detector to the usual

concentration-sensitive detector. However, this does not allow

the extrapolation to zero scattering angle which is required, in

principle to relate scattering intensity to molecular weight. In

47
Table 8. Comparison of Thin-Film Test Results With

and Without Fuel Catalysts

Test Conditions: 1.5 g Oil

160 °C

2% water

620 KPa Initial Oxygen (90 psig)

Oil HID Hours**

HID Pass***

or Fail

Thin-Film Test

Induction Time (min)

Without

Cu & Fe wires

With

5 wt% Fuel

5 wt% Metal

76A-1 62 Pass > 590 273

75B-1 56 II 395 193

73B-1* 48 II — 116

79A 40 II 254 155

81

A

40 II — 101

77B-1 24 Fail 245 60

77C 16 II 181 44

72A-1 16 II 181 39

*High wear oil (fail wear criterion)

.

**Hours for 375% viscosity increase in sequence HID engine test.

***An oil is a pass oil if its HID engine test viscosity increase at

40 hr. is less than 375%; otherwise the oil is a fail oil.

Note: Test repeatability is + 5%.

48
addition, qualitative information on the variation of scattering

with angle, normally required to give assurance that meaningful

results are being obtained, is not available.

We are designing and constructing a light scattering

detector for the GPC which measures; in real time, the scattering

intensity as a function of scattering angle and which is

controlled by a dedicated minicomputer in a way that allows

scattering to be measured as a function of scattering angle and

concentration. The instrument will allow continuous monitoring

of the variation of scattering with angle. This will allow

immediate identification of difficulties such as association,

microgel formation, etc., which could affect the validity of the

molecular weight obtained, an important consideration for work on new and unstudied materials. In addition to molecular weight,

the mean-square radius (radius of gyration) will be obtained as a function of molecular weight, at least in the higher ranges of

molecular weight, providing useful information for the

characterization of branched polymers.

In FY83 we will start making measurements with the completed

instrument and developing procedures for high-quality molecular

weight determinations.

. 20 Metallurgical Research

A. W. Ruff

Metallurgy Division

Center for Materials Science

Five projects are underway involving Standard Reference

Materials. One project involves the development and

certification of a Standard Reference Material (SRM) for use with

the new Dry Sand/Rubber Wheel Abrasion Test (ASTM Standard

365 -80). Appro xi mate 1 y 250 specimens of D-2 tool steel, the

material which was selected for this application, have been

prepared. Certification tests using NBS equipment have been

completed and the statistical analysis and writing of the

certification statement are expected to be completed in FY83.

An additional 750 SRM specimens are being prepared for later

issue. Publication of ASTM G65-80, "Standard Practice for

Conducting Dry Sand/Rubber Wheel Abrasion Tests" has evoked

considerable interest among producers of abrasive wear resistant

materials, manufacturers of equipment subject to abrasive wear,

and users of these materials and equipment. The Dry Sand/Rubber

Wheel wear test is especially applicable for ranking materials

exposed to conditions involving so-called three-body abrasion as might be encountered in earth moving and agricultural equipment,

in mining, and certain ore processing machinery. A workshop

sponsored by ASTM Committee G-2 on Erosion and Wear was held in

June for the specific purpose of addressing problems which might

be encountered in applying this Dry Sand/Rubber Wheel test, and

to consider the influence that changes in various test conditions

49
and parameters might have on test results. The importance of a suitable calibration specimen was clearly recognized during the

course of this workshop. We contributed one paper to the

workshop illustrating the effect of sand flow rate and moisture

content on the wear rate using this test.

Another project is investigating the feasibility of using

new metal processing techniques such as electron-beam (EB)

surface melting and fiber melt spinning to produce microhardness

standards. This work was supported by the Office of Standard

Reference Materials and was conducted in conjunction with the NBS

Electrodeposition Group (D. Lashmore, Materials Chemistry

Division). Electron-beam surface melting techniques developed in

the Metallurgy Division processing laboratory were used on 440C

stainless steel bar stock to see whether areas of sufficient

homogeneity of microhardness suitable for low load microindentation testing (0. 098-0. 98N loads) could be produced.

Although the EB zones in the stainless steel were quite microstructurally uniform, electroformed Cu-based materials with a similar microhardness range showed much better reproducibility of

mi crohardness numbers. The decision was made to produce electroformed Cu standards for this reason. Work continues on char acter i zi ng melt-spun ribbons of PdsoGe20 for possible use as standards in other microhardness number ranges. Additional work

on characterizing heat-treated, electroformed Co-based materials

for standards is planned for the coming year, also in conjunction

with the Materials Chemistry Division.

One project supported by the Office of Standard Reference

Materials concerns the development of standards for use with the

ferrographic method of analysis of wear debris particles in

lubricants. This method has proven itself as a viable condition

monitoring tool; however, the quantitative capability

involved needs improvement. After participating in several

i n ter 1 abor atory measurement rounds, it became clear that certain

problems of precision and bias could be overcome if adequate

standards were available. Development of an artificial sample of

wear is now in progress, and should help to further quantify the

overall method.

Quantitative image analysis was employed in a project

completed this year to aid in the development of standardized

methods for characterizing the geometric shapes of sand particles

for use in dry sand/rubber wheel (DSRW) tests. A perimeter ratio

(PR) parameter was used to evaluate the variations in abrasive

sand particle shapes in batches of sand used in testing over a several year period. These ratio parameters remained very

constant from batch to batch in the rounded AFS 50-70 sand

specified for the ASTM DSRW procedure. Sharper particles

produced by crushing quartz and screening it to the same sieve

size range as the AFS 50-70 sand had larger PR parameters to

start with and produced greater amounts of abrasive wear on steel

samples. Image analysis comparing both used and unused sand

showed that the average PR parameters for AFS 50-70 and for

50
crushed quartz remained relatively constant before and after the

abrasion tests. However, there appeared to be increases in the

standard deviations of PR parameters of both kinds of abrasives

after use in DSRW tests. Further work is planned using a new

image analysis system to investigate larger sample sizes and to

more completely automate the shape classification procedure.

This future work should improve the statistical significance of

PR data by shortening the time required to analyze larger numbers

of particles.

Another project is concerned with the need to develop

performance standards for medical and surgical devices. The test

methods developed in ASTM, for example, for materials can be used

for this purpose. This past year, the ASTM F746-82 "Standard

Method of Test for Pitting or Crevice Corrosion of Metallic

Surgical Implant Materials" was passed. NBS participated for

many years with other university and industrial laboratories in

developing this test and conducting interlaboratory tests. This

is the first standard corrosion test for surgical implant metals,

and it will be followed by the production of the NBS 316L

stainless steel Standard Reference Material (SRM) for use with

the standard test. NBS has obtained 316L stainless steel for use

as Standard Reference Material from the supplier who furnished

the round-robin specimens and who supplies implant manufacturers.

Work on the SRM production is underway and some studies to refine

the test are being conducted in terms of effects of solution

oxygen content, solution pH and metal surface condition.

. 21 Computer Magnetic Media

S . B . Ge 1 1 er

System Components Division

Institute for Computer Sciences

and Technology

(1) Minicassette Magnetic Tape SRM's

Four Raymond Mi n i -Raycorder Model 6409 minicassette drives,

and 50 minicassettes were obtained. A field control unit was

designed in order to control the forward and reverse motion of

the media as well as the on-off read/write control functions.

Some logical card functions were redesigned in order to allow for

both frequency and automatic current level controls. Initial

signal amplitude tests were performed through the use of the NBS

reference measurement system. The results of these tests,

although preliminary, indicated that these very inexpensive

Model 6409 drives do not appear to have the speed stability which

will be required from SRM reference machines. At the present

time, it is uncertain whether it will be cost effective to

finance the design of a precision minicassette reference drive if

one is not available commerc i a 1

1 y

.

51
(2) Very High Density Magnetic Tape Cartridge SRM's

No commercial announcements were made until late FY82

relative to the release of new high density products. Maintained

contact with technical personnel directly engaged in the

development of these products and was advised that products will

be available during FY83. This high density program will receive

a high priority in FY83.

(3) Care and Handling of Computer Magnetic Media Special

Publication

The following sections are at least 90 percent completed:

1. Environmental recommendations and remarks.

2. Clean operations recommendations and remarks.

3. Technical handling recommendations and remarks.

4. Causes for data losses on computer storage media.

5. Scheduled tape maintenance.

6. Description of equipments for cleaning, certifying,

and evaluating tapes.

7. Tape rehabilitation processes.

8. Clean room theory and types of rooms.

9. Guidelines for operations in clean room of all classes.

10. Effects of various external fields on data stored on

magnetic tapes.

11. Effects of temperature, humidity, and winding methods

on magnetic tapes.

12. The care and handling of computer tapes in long-term

archival storage.

a) Results obtained from large tape populations.

b) Results derived from an experimental and

theoretical study based on small sample

stati sties

.

c) Recommended care and handling methods based on a)

and b )

.

. 22 Absolute Layer Thickness Measurements for Semiconductor

Mater i al

s

D. Nyyssonen

Semiconductor Materials and Processing Division

Center for Electronics and Electrical Engineering

The initial efforts on this project, begun in FY81, were

directed toward 1) the design and fabrication of test patterns

suitable for both the controlled characterization of the

thickness and step-height of dielectric layers fabricated on

silicon substrates and 2) the critical evaluation of available

measurement techniques, including stylus prof i lometry

,

i nterf eromet ry , and e 1 1 i psometry . In FY81, the test pattern

52
4. OSRM STAFF PUBLICATIONS, INFORMATION TRANSFER AND COMMITTEE

ACTIVITIES

4.1 Publications, Journal Articles, and Written Reports by OSRM

Staff in FY82

--Alvarez, R., "National Bureau of Standrds Standard Reference

Materials Certified for Arsenic," sent 11-25-81 to be published

in Proceedings of Arsenic Symposium Sponsored by Chemical

Manuf acturers Association and NBS. Held at NBS Nov. 4-6, 1981.

--Alvarez, R., "Report on Reference Materials and Standard

Solutions," J. Assoc. Off. Anal. Chem. , 6_5, 297 (March 1982).

--Alvarez, R., Rasberry, S. D. and Uriano, 6. A., "NBS Standard

Reference Materials: Update 1982," Anal . Chem . (to be

p u b 1 i s h e d 0 c t . 19 82 ).

--Alvarez, R., "Citrus Leaves (SRM 1572); a New NBS Plant Tissue

SRM Certified for trace Element Concentration," Proceedings of

the Ninth International Plant Nutrition Colloquium, available

Commonwealth Agricultural Bureaux, Farnham House, Farnham

Royal, Slough SL2 3BN, U.K.

--Garner, E. L., Gills, T. E. and Moore, L., "Current Status of

NBS Isotopic Standards and Future Role of SRM's for Nuclear

Energy," Proceedings of the 30th Annual Conference of the

American Society for Mass Spectrometry and Allied Topics,

Honolulu, Hawaii, June 1982.

--Kirby, R. K., "Recent Activities of the National Bureau of

Standards and the American Society for Testing and Materials

in Developing Particulate Standard Reference Materials,"

Proceedings of the Third Symposium on Advances in Particle

Sampling and Measurement, Daytona Beach, Florida,

October 21 , 1981

.

--Rasberry, S. D., ed . , "Reference Materials,"

Laboratory , L3 (10) pp. 159-160 (1981).

--Rasberry, S. D., ed . , "Reference Materials,"

Laboratory , (11) pp. 156-157 (1981).

--Rasberry, S. D., ed . , "Reference Materials,"

Laboratory , 1

3

(12) p. 84 (1981).

--Rasberry, S. D., ed . , "Reference Materials,"

Laboratory , 1

4

(1) pp. 112-115 (1982).

--Rasberry, S. D., ed . , "Reference Materials,"

Laboratory , 14 (2) pp. 182-186 (1982).

Amer i can

American

Amer i can

American

Amer i can

53
--Rasberry , S . D . , ed .

,

Laboratory , 14 (3) p.

"Reference Materials,"

178 (1982).

--Rasberry, S. D., ed .

,

Laboratory , 14 (4) p.

"Reference Materials,"

114 (1982).

American

Amer i can

--Rasberry, S. D., ed .

,

Laboratory , 1_4 ( 5 ) p

.

"Reference Materials,"

142 (1982).

--Rasberry , S . 0 . , ed .

,

Laboratory , 14 (7) p.

"Reference Materials,"

80 (1982).

Amer i can

Amer i can

--Rasberry, S. D., ed . , "Reference Materials," American

Laboratory , 14 (8) pp. 76-77 (1982).

--Rasberry, S. D., ed . , "Reference Materials," American

Laboratory , 14 (9) pp. 140-141 ( 1982).

--Uriano, G. A. and Rasberry, S. D., eds., "Annual Report 1982 - Office of Standard Reference Materials (1982).

4 . 2 Technical Lectures/Talks Given by OSRM Personnel

--Alvarez, R., "What Committee E-2 Should Know About Non-Metal

SRM's," ASTM Committee E-2 on Emission Spectroscopy Symposium

held at the National Bureau of Standards, Oct. 1, 1981.

--Alvarez, R., "Role of National Bureau of Standards Standard

Reference Materials in Quality Assurance Programs for

Heal th -Rel ated Analyses," 95th Annual Meeting, Association

of Official Analytical Chemists, Marriott Twin Bridges,

Washington, D.C., Oct. 20, 1981.

--Alvarez, R., General Referee's Report on Reference Materials

and Standard Solutions, 95th Annual Meeting, Association

of Official Analytical Chemists, Marriott Twin Bridges,

Washington, D.C., Oct. 20, 1981.

--Alvarez, R., "National Bureau of Standards Standard Reference

Materials Certified for Arsenic," Arsenic Symposium (Session

II), sponsored by the Chemical Manuf act urer s Association and

NBS, Office of Environmental Measurements, held at NBS,

Gaithersburg, MD, Nov. 4, 1981.

--Alvarez, R., "New developments in Standard Reference

Materials," Chemical Society of Washington, Catholic

University, Washington, D.C., Nov. 12, 1981.

--Alvarez, R., "New Clinical, Environmental, and Other HealthRelated National Bureau of Standards Standard Reference

Materials and Their Application in Laboratory Quality Control,"

54
Department of Health Services, Berkeley, CA, March 26, 1982.

-Alvarez, R., "National Bureau of Standards Standard Reference

Materials Certified for Constituents of Environmental

Importance, "American Chemical Society, Las Vegas, NV

March 29, 1982.

-Alvarez, R., "New Developments in Clinical and Other Health

Related Standard Reference Materials for Quality Assurance

Applications," Las Vegas, Nevada, March 31, 1982.

-Alvarez, R., "New National Bureau of Standards Environmental

Standard Reference Materials Certified for Priority

Pollutants," Las Vegas, Nevada, March 31, 1982.

-Alvarez, R., "NBS Standard Reference Materi al s--Their Use in

Determining and Maintaining Measurement Accuracy," Maryland

Junior Academy of Sciences, Maryland Science Center,

Baltimore, MD, April 17, 1982.

-Alvarez, R., "Recent Developments in NBS Standard Reference

Materials and Their Role in Laboratory Quality Control,"

Society for Applied Spectroscopy - Florida Section, University

of Florida, Gainesville, FL, April 19, 1982.

-Alvarez, R., "Recent Developments in NBS Standard Reference

Materials and Their Role in Laboratory Quality Control,"

Society for Applied Spectroscopy - Houston Section,

Houston, TX, April 20, 1982.

-Alvarez, R., (same title as 4-20-82), Society for Applied

Spectroscopy - Indiana Section, Indianapolis, IN,

April 21, 1982.

-Alvarez, R., (same title as 4-20-82), 4th Midwest Analytical

Chemistry Symposium, Columbia, MO, April 22, 1982.

-Alvarez, R., "Recent Developments in National Bureau of

Standards Standard Reference Materials and Their Role in

Laboratory Quality Control," 4th Midwest Analyltical Chemistry

Symposium, Columbia, MO, April 22, 1982.

-Alvarez, R., "Standard Reference Materials" (in Spanish), The

American Institute of Foreign Study (Visitors from Spain),

NBS, G ai t her sburg , MD, July 12 , 1982 . -Alvarez, R., "The Catalytic Concentration of Seven Enzymes

in Lyophilized Human Serum, NBS SRM 909," - Co-author, American

34th National Meeting, American Association for Clinical

Chemistry, Anaheim, CA, Aug. 13, 1982.

-Alvarez, R., "Citrus Leaves (SRM 1572) - A New NBS Plant Tissue

55
Standard Reference Material Certified for Trace Element

Concentrations," Ninth International Plant Nutrition

Colloquium, Coventry, U.K., Aug. 24, 1982.

-Alvarez, R., "New Development in NBS Environmental Standard

Reference Materials," VIII Annual Meeting of the Federation of

Analytical Chemistry and Spectroscopy Societies, Philadelphia,

PA, Sept. 22, 1982.

-Alvarez, R., "New National Bureau of Standards Food and Plant

Tissue Standard Reference Materials Certified for Trace Element

Concentrations," VIII Annual Meeting of the Federation of

Analytical Chemistry and Spectroscopy Societies, Philadelphia,

PA, September 23, 1982.

-Gills, T. E., (invited talk) "The Role of NBS Standard

Reference Materials in Measurement Systems for Environmental

Analysis and Monitoring," Pittsburgh Conference and Exposition,

Atlantic City, NJ, March 1982

-Gills, T. E., (invited talk) "SRM's in Environmental

Measurement," Department of Chemistry, University of Maryland,

College Park, MD, April 1982.

-Kirby, R. K., "Standard Reference Materials," ASTM Committee

E-37, Philadelphia, PA, April 5, 1982.

-Kirby, R. K. and Alvarez, R., "Standard Reference Materials for

Quality Assurance of Clinical Measurements," 34th National

Meeting of the American Association for Clinical Chemistry,

Anaheim, CA, Aug. 12, 1982.

-Rasberry, S. D., "The Role of SRM's in Quality Assurance Center

for Professional Advancement Course on Qu alii ty Assurance, East

Brunswick, NJ, Jan. 26, 1982.

-Rasberry, S. D., "The Role of SRM's in Quality Assurance,"

NBS Course on Quality Assurance, Gaithersburg, MD,

May 27, 1982.

-Reed, W . P . , "Preparation and Certification of Standard

Reference Materials," Seminar sponsored by NBS Center for

Analytical Chemistry, Inorganic Analytical Research Division,

Gaithersburg, MD, April 15, 1982.

-Uriano, G. A., "Overview of the NBS Standard Reference

Materials Program," Presentation to Deputy Secretary of

Commerce, Guy Fiske, NBS, Gaithersburg, MD , March 17 , 1982 . -Uriano, G. A., "The NBS Office of Standard Reference

Materials," Directors of Industrial Research Analytical

Group Meeting, NBS, Gaithersburg, MD, May 7, 1982.

56
--Uriano, G. A., "The Development of a Trace Elements in Human

Serum Standard Reference Material," Interagency Working Group

on Blood Resources and Blood Substitutes, National Institutes

of Health, Rockville, MD, June 1, 1982.

4 . 3 Standards Committee and Other Standards Activities

Alvarez, R. - American Society for Testing and Materials (ASTM)

Subcommittee on Reference Materials and

Sol utions

General Referee for Reference Materials

American Society for Testing & Materials (ASTM)

E-02 - Emission Spectroscopy

E-02.05 - Copper, Nickel, and High

Temperature Alloys

Gills, T. E. - American Society for Testing and Materials (ASTM)

C-26 on Nuclear Fuel Cycle

C-26.05 Test Methods

Kirby, R. K. - American Society for Testing and Materials (ASTM)

E - 29 on Particle Size Measurement

E - 3 7 on Thermal Measurement

E-37.02 on Standard Reference Materials

E-37.05 on Thermal Properties

S - 2 1 Coordinating Committee for Standard

Reference Materials for Particle

Met ro 1 ogy

C - 1 4 on Glass and Glass Products

C-14.91 on Standard Reference Materials

Rasberry, S. D. - American Society for Testing and Materials

(ASTM)

E-02 on Emission Spectroscopy

C-14.91 on SRM's for the Glass Industry

U.S. Pharmacopeia (Delegate)

Agency for International Development (Standards

Assistance to Egypt)

Reed, W. P. - American Society for Testing and Materials (ASTM)

E-2 on Emission Spectroscopy

E-3 on Chemical Analysis of Metals

C-26 on Nuclear Fuel Cycle

C-26. 07 on Waste Materials (Chairman)

S - 1 7 ASTM-NBS Research Associate Program

American National Standards Institute

N 1 5 Nuclear Standards

Seward, R. W. - American Society for Testing and Materials (ASTM)

E - 1 3 on Molecular Spectroscopy

E-13.01 on UV and Visible Spectroscopy

57
Uriano, G. A. - American Society for Testing and Materials (ASTM)

E - 0 2 on Emission Spectroscopy

U.S. Delegate to ISO Council Committee on Reference Materials (REMCO)

Chairman of ISO/REMCO

Consultant to Standards Committee, American

Association for Clinical Chemistry

Vice Chairman, Secretary and Titular Member of

Commission 1.4 on Physico-chemical Reference

Materials and Standards, International Union of

Pure and Applied Chemistry

Consultants' Panel on Analytical Quality Control,

International Atomic Energy Agency, United

Nations

Consultants' Panel on Coal Reference Materials,

Basic Energy Sciences Division, U.S. Department

of Energy

4 . 4 NBS Special Publication 260 Series

The OSRM is responsible for the publication and

dissemination of information on all phases of the preparation,

measurement, certification, and utilization of SRM's. One of the

major mechanisms for carrying out this responsibility is the

publication and distribution of the NBS Special Publication 260

Series on SRM's. Since 1964 over 70 SP 260 reports --authored

primarily by technical division staff--have been published,

describing the preparation and use of a variety of SRM's and

associated measurement methods. In FY82, the following SP 260 '

s

were published by OSRM:

--Mar i nenko , R. B., Standard Reference Materials: Preparation

and Characteri zat i on of K-411 and K-414 Mineral Glasses for

Mi croanalysi s : SRM 470, NBS Spec. Publ. 260-74 (April 1982)

S3. 50.

--Weidner, V. R., Hsia, J. J., Standard Reference Materials:

Preparation and Calibration of First Surface Aluminum Mirror

Specular Reflectance Standards (SRM 2003a), NBS Spec. Publ.

260-75 (May 1982) $3.75.

--Hicho, G. E. and Eaton, E. E., Standard Reference Materials:

A Standard Reference Material Containing Nominally Five Percent

Austenite (SRM 485a), NBS Spec. Publ. 260-76 (August 1982) S3. 50.

--Furukawa, G. T., Riddle, J. L., Bigge, W. G . , and Pfieffer,

E. R., Standard Reference Materials: Application of Some Metal

SRM's as Thermometric Fixed Points, NBS Spec. Publ. 260-77

( August 1982 ) $6.00.

--Hicho, G. E. and Eaton, E. E., Standard Reference Materials:

58
Standard Reference Material Containing Nominally Thirty Percent

Austenite (SRM 487), NBS Spec. Publ. 260-78 (Sept. 1982) $3.75.

NOTE : To order these publications, send order with remittance

( add 25 percent for other than U.S. mailing) to Superintendent of

Documents, U.S. Government Printing Office, Washington, DC 20402.

For further information, contact the Office of Standard

Reference Materials, Room B - 3 1 1 , Chemistry Building, National

Bureau of Standards, Washington, DC 20234. Telephone: (301)

921-2045.

4 . 5 FY82 Technical Exhibits With Staffed SRM Displays

Pittsburgh Conference on Analytical Chemistry and

Applied Spec troscopy , Atlantic City, NJ,

March 7 -12 , 1982 .

Amer i can Chemical Society Meeting, Las Vegas, NV,

March 25-April 2, 1982.

Society of Nuclear Medicine, Miami, FL,

June 14-18, 1982.

Air Pollution Control Association Meeting, New Orleans,

LA, June 21-25, 1982.

Nuclear Materials Management, Washington, DC,

July 19-21, 1982.

American Association for Clinical Chemistry Annual

Meeting, Anaheim, CA, August 9-13, 1982.

Federation of Analytical Chemistry and Applied

Spectroscopy Societies, Philadelphia, PA,

September 19-24, 1982.

Labcon, Chicago, IL, September 28-30, 1982.

59
NBS-114A (rev. 2-bc) U.S. DEPT. OF COMM. 2. Performing Organ. Report No. 3. Publication Date BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO.

NBSIR 83 - 2649

4.

TITLE AND SUBTITLE

1982 Annual Report

Office of Standard Reference Materials

5.

AUTHOR(S)

G. A. Uriano and S. D. Rasberry, Editors

6.

PERFORMING ORGANIZATION (If joint or other than N BS, see instructions)

national bureau of standards

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

9.

SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City, State. ZIP

)

10.

SUPPLEMENTARY NOTES

Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11.

ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliograohy or literature survey, mention it here)

This report summarizes the technical activities of the Standard

Reference Materials (SRM) program of the National Bureau of Standards.

Status reports for SRM research and production projects are included

in the areas of electrical properties, thermal properties, radioactivity,

chemical composition, chemical stability, mechanical properties and

optical properties. Projects covered are carried out by technical

centers in the National Measurement Laboratory, National Engineering

Laboratory, and the Institute for Computer Sciences and Technology.

Also covered are a number of cooperative projects with other laboratories

and SRM activities of a number of industrial research associates.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Analytical Chemistry; compositional analysis; physico-chemical

properties; quality assurance; reference methods; Standard Reference

Materi al

s

13. avAIl.aBIL.ITY

Unlimited

QQ For Official Distribution. Do Not Release to NTIS

(331 Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402. 33 Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

15. Price

USCOMM-DC 6043-P80
I