AlllOO TTMMMS NBS

PUBLICATIONS

NBSIR 81-2280

Technical Activities of the Office of

Environmental Measurements— 1 980

William H. Kirchhoff, Chief

Office of Environmental Measurements

National Measurement Laboratory

U.S. Department of Commerce

National Bureau of Standards

Washington, DC 20234

May 1981

Prepared for: National Bureau of Standards

Q0MM«epartment of Commerce

2

Washington, DC 20234

,U56

81-2280

1981

c.2

NBSIR 81-2280

TECHNICAL ACTIVITIES OF THE OFFICE OF

ENVIRONMENTAL MEASUREMENTS-1 980

RATIONAL 1SVKEAI OP tTAWBARUa

LIBBART

JUL 2 0 1981

(Suc£

cc

no. vmi

William H. Kirchhoff, Chief

Office of Enviornmental Measurements

National Measurement Laboratory

U.S. Department of Commerce

National Bureau of Standards

Washington, DC 20234

May 1981

Prepared for: National Bureau of Standards

Department of Commerce

Washington, DC 20234

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

NATIONAL BUREAU OF STANDARDS. Ernest Ambler. Director

TECHNICAL ACTIVITIES

Table of Contents

Disclaimer

Abstract ! ii

Introduction iii

WATER MEASUREMENTS - STANDARDS DEVELOPMENT - -1

Standard Reference Materials for Organics in Water: Project Description 3

Selected Technical Accomplishments

Certification of Generator Columns for Polynuclear Aromatic

Hydrocarbons in Water (SRM 1644) 5

Determined Aqueous Solubilities and Chromatographic Characteristics

for Organic Compounds on the Priority Pollutant List 7

Developed and Evaluated a Quenchofluorometric Detection System for

Chlorinated Pesticides 7

Liquid Chromatographic Retention Characteristics of Polycyclic

Aromatic Hydrocarbons 14

Stability Study of Halohydrocarbons 14

Developed Alternate Proposal for Quality Assurance of PAH Measurement

in Water 16

Environmental Radioactivity Measurements : Project Description 18

Selected Technical Accomplishment

Provided Services to EPA/Las Vegas Under the Measurement Traceability

Program 22

Evaluated Monitoring Methods for Radium-228 and Issued a Report 23

1 33

Developed a Sampling Procedure for Calibration of Xe-Air Mixtures 23

Seven Natural Matrix Materials Have Been Dried, Ground, Homogenized,

and Bottled 24

Hazardous Waste Characterization : Project Description 36

Selected Technical Accomplishment

Characterization of Potentially Hazardous Waste-Development of

Rotary Extractor and Quality Assurance Standards 39
Energy-Related Organic and Inorganic Water Standards Development:

Project Description — —---41

Selected Technical Accomplishments

First Natural Matrix Trace Organic SRM Issued for Shale Oil SRM 1580—42

GC/MS Analysis of Aqueous Effluents from Coal Conversion Processes-— --45

Application of Multi-Dimensional Chromatography to Trace Organic

Compound Quanti tati on —------ -----51

Combined LC/MS Technique for Direct Quantitative Analysis for

Individual Organic Compounds in Complex Mixtures — “-------51

Work Plan and Evaluation/Feasibility Study of Drilling Fluid

Reference Standards for Chemical Analysis----- —-------52

Atomic Absorption and Flame Emission Spectrometry- — --------54

Metal Speciation Using High Performance Liquid Chromatography/Atomic

Absorption Spectrometry- _56

Interferences in the Inductively Coupled Plasma (ICP) Technique ----60

Radiological Pollutant Quality Assurance : Project Description- —.————61

Accompl ishments

O'iO J ^Th Solution — -61

Mixed Radionuclide Solutions- — — —-----61
WATER MEASUREMENTS - METHODS DEVELOPMENT 70

Methods Development for Organic Analysis : Project Description 72

Selected Techncial Accomplishments

Synthesis, Isotopic and Purity Analyses, and Preparation of

Solutions of Stable Isotope Labeled Marker Compounds for

Priority Pollutant Analysis 72

Fluoroimmunoassay Procedure Developed for Dinitrophenols in Water 74

Correlation of Liquid Chromatographic Retention Data, with Molecular

Shapes for Polycyclic Aromatic Hydrocarbons 75

Liquid Chromatography with Electrochemical Detection (LC-EC) 76

Development of a Fourier Transform Infrared Spectrometer- Gas

Chromatograph Interface and Its Application to Pollutant

Identi fi cation 82

Laser Analysis of Pollutants in Cryogenic Matrices 83

Methods Development for Inorganic Analysis ; Project Description 84

Selected Technical Accomplishments

Trace and Toxic Elemental Study of the Chesapeake Bay 84

Sulfur Speciation in Coal 87

Ionic Chromium Speciation Measurements 88

AIR MEASUREMENTS - STANDARDS DEVELOPMENT - 90

Standard Reference Material and Reference Method for Asbestos in Air:

Project Description 92

Project Progress —97

Standard Reference Materials (SRM's) for Toxic Organics in Air:

Project Description-- 103

Project Progress 108

Acid Precipitation Quality Assurance Samples: Project Description 111

Project Progress 112

Air Generator Columns: Project Description 114

Project Progress 114
Ozone Photometers: Project Description---- 117

Project Progress —- ——118

Energy-Related Gas Standards Development: Project Description— -----120

Project Progress---— -----120

Energy-Related Particulate Standards Development:

Project Description--- — —124

Project Progress- 124

AIR MEASUREMENT - METHODS DEVELOPMENT

Personal Exposure Monitors: Project Description-------- — 1 34

Project Progress-—-- 1 39

Calibration and Measurement Technique Development for UV

Radiometry : Project Description---------- .-..—-------=.-----.----147

Project Progess —148

Energy-Related Gas Methods Development : Project Description---- 151

Selected Technical Activities

Standards for Measurement of Atmospheric Carbon Dioxide— -------152

Intercomparison of 0 V NO and N0? Measurement Standards by Gas

Phase Titration-— ————————— 1 53

Energy-Related Particulate Methods Development : Project Description-156

Selected Technical Activities

Particle Doppler Shift Spectrometer (PDSS)———————157

Measurement of Ambient Sulfur Aerosols by a New Fast Response

Flame Photometric Instrument-- —---- —-157

Radiocarbon as an Environmental Tracer————————————160

Envi ronmental Assessment---' — --1 77

INTERACTIONS AND OUTPUTS

Publ i cations— — ----1 79
APPENDIX

NBS Organization Chart 180

NML Organization Chart 181

OEM Organization Chart 182

Functional Statement, OEM 183
I

'
DISCLAIMER

"Certain commerical equipment, instruments, or materials are identified

in this paper in order to adequately specify the experimental 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."

i
ABSTRACT

This report summarizes the technical activities of the National Bureau

of Standards' Environmental Measurements Program during Fiscal Year 1980.

These activities fall into four program categories:

1. Water Measurements - Standards Development

2. Water Measurements - Methods Development

3. Air Measurements - Standards Development

4. Air Measurements - Methods Development

Key Words: Air; water; environmental measurements; methods; quality

assurance; standards
INTRODUCTION

This report summarizes the technical activities of the National Bureau

of Standards' Environmental Measurements Program for the period October

1, 1979 to September 30, 1980. The Program is administered by the Office

of Environmental Measurements (OEM) which is one of seven program offices

in the National Measurement Laboratory concerned with the development

and/or provision of various services in particular areas that rely upon

a variety of disciplines located in NBS Centers. The technical work

described in this report was performed by scientists located in three

Centers - the Center for Analytical Chemistry, the Center for Radiation

Research and the Center for Chemical Physics.

The primary goal of the NBS Environmental Measurements program is to

provide standards of measurement to insure proper assessment of national

environmental goals and to allow the attainment of these goals with the

minimum of economic and energy penalty. For several years, the NBS

Environmental Measurement Program was supported by direct Congressional

appropriation. However, in fiscal year 1979, in response to an Office

of Management and Budget (0MB) ruling, NBS activities in environmental

measurements were required to be coordinated with and supported by the

Environmental Protection Agency (EPA), the lead agency for achieving

national environmental objectives. Therefore, the Environmental Measurements Program currently receives nearly 90% of its support from EPA and the

majority of the technical activities summarized in this report are related to and in support of larger programmatic objectives of the

of EPA Office of Monitoring and Technical Support.

The technical activties are described under four main headings: Water

Measurements - Standards Development; Water Measurements - Methods

Development; Air Measurements - Standards Development; Air Measurements - Methods Development. An overview is given for each activity along with

the staff members associated with that activity and selected highlights.

A list of OEM publications for the year are listed at the end of this

report.

A detailed Table of Contents has been provided which will permit the

reader to find those activities of greatest interest. If more information about particular work is desired, the reader can address the

individual scientists, c/o Office Environmental Measurements, National

Bureau of Standards, Bldg. 220, Room A261 , Washington, DC 20234 or contact this office by telephone (301 ) -921 -3775

.

WATER MEASUREMENTS - STANDARDS DEVELOPMENT

a. Overview

The scope of the national program in water pollution control is

mandated by recent Federal legislation and involves the efforts of municipal

and state government agencies, industries, water suppliers and nearly

every department in the Federal Government. Measurement forms the basis for

nearly all decisions concerning water pollution. This task addresses the

development of standards and Standard Reference Materials to assure accurate

and compatible measurement throughout the water pollution measurement

system and minimize the uncertainty associated with quantifying the extent

of water pollution.

Objective

Provide measurement standards that are required to achieve accurate

measurements of: (1) the concentration of chemical pollutants in water;

(2) the chemical and physical properties of identified pollutants in water;

and (3) the physical properties of water, such as velocity and flow. Water

pollution standards developed in this task will provide an accurate, rational

and equitable basis for the development and enforcement of water pollution

regulations

.

Interactions

Strong interactions are maintained with other units of the NBS community

(Center for Analytical Chemistry, Office of Standard Reference Materials,

Center for Radiation Research, Center for Thermodynamics and Molecular

Science, Office of Standard Reference Data, Office of Recycled Materials,

Center for Materials Science, Center for Mechanical Engineering and

Process Technology, Center for Applied Mathematics, Office of Nuclear

Waste Management), and with other Federal Agencies- (EPA, DOE, NOAA).

The activities in this task also involve interactions with industry,

state and local governments, research laboratories, universities, as well as with other organizations (e.g.. Council on Environmental Quality, ASTM) engaged in related activities which impact the development of

standards for water pollution measurements.

Task - Justification

The national effort in water pollution abatement involves municipal

and state government agencies, industries, water suppliers and nearly

every department of the Federal Government. In response to water pollution legislation (P.L. 92-500, P.L. 93-523), there has been an increase in water monitoring to determine progress toward national en- vironmental goals, and to enumerate in quantitative terms regulations to

achieve those goals. The national effort in water pollution abatement

depends upon accurate and reliable measurement necessitating the need

for accurate standards against which water pollution measurements can be

1
compared. Without accurate measurements scientists cannot relate health

effects to levels of water pollution correctly, engineers cannot assess

the effectiveness of control techniques correctly, and regulatory

agencies cannot relate levels of pollution effluents with water quality

correctly nor can compliance with water pollution regulations be fairly

and equitably tested.

b. List of Projects

Project Title Source of * Funding

(1) Toxic Organics - Water

(2) Environmental Radioactivity

P/T - EPA

Measurements P/T - EPA

(3) Hazardous Waste Quality Assurance

Samples P/T - EPA

(4) Energy Related Water Standards

(Organic and Inorganic) E/E - EPA

(5) Radiological Pollutant Quality

Assurance E/E - EPA

*P/T = Pass-Through Funding

E/E = Energy/Environment Funding

2
c. Project Description

(1) Standard Reference Material (SRM) for Organics in Water

Participating Staff: Center for Analytical Chemistry

Goal

:

Assist EPA in achieving and maintaining quality assurance in

the measurement of organic pollutants in water by providing

standards against which organic water pollution measurements

can be compared and measurement technology tested.

Background:

The size of the chemical industry, the number of compounds

that exist, and their pervasiveness, all seem to make the regulatory task of protecting the aquatic environment particularly

challenging. It has been estimated that >70,000 chemicals are currently in use. Although only a small number of these compounds

are toxic, the risk to human health and the effect on the aquatic

environment is/will be the focus of attention now and for several

years to come. One of the largest classes of compounds is organics,

which are used widely in industry as precursors In the manufacture

of synthetics and as solvents in various commercial operations. To

identify and measure the concentration of organics in water, EPA/CINC

conducts monitoring programs for organic compounds.

Essential to a successful monitoring activity is availability of

certified Standard Reference Materials (SRM) in the measurement

range of interest. Such standards are needed for calibration of

the measurement technique and in quality assurance activities

necessary to determine the precision and accuracy of the monitoring

data collected. Organic standard materials having certified con- centrations of organics for use with water monitoring programs have

not been available, because the analytical methodology needed to

produce such standard materials had to be developed first. NBS has

developed the capabilities which now enables it to respond to some

of the organic standard needs (capability/methodologies to characterize and produce inorganic SRM's already existed for many

years). This work plan for FY-80-81 addresses the development of

organic SRM's for use by EPA/CINC in their monitoring and quality

assurance programs.

Scope:

Utilizing the generator column concept, as well as other analytical

methodologies, NBS will provide SRM's for the measurement of selected

organic priority pollutants.

3
Milestones:

1. Determine the solubilities of representative

priority pollutants in order to assess the

feasibility of generator column SRM's.

2. Assess the feasibility of preparing pesticide

generator column SRM's for compounds to be

identified by EMSl/CINC.

3. Complete certification of three generator

columns (benzo(a)pyrene; benz(a)anthracene;

anthracene)

4. Conduct a workshop at EPA/CINC, for participants selected by EPA/CINC s on the

use/ technique of generator column standards

5„ Assess the feasibility of three pesticide

generator columns to be selected by EPA/CINC

from a previously proposed list

6. Complete the stability study for the halocarbons in water SRM

7. Prepare a SRM package for evaluating

extraction efficiencies of PAH's from

aqueous solution and conduct a "roundrobin" experiment with (a) a predetermined

set of generator columns and (b) an acetonitrile solution of the 16 priority

pollutant PAH's listed in EPA Interim Method

610®

8. Conduct a round- robin experiment with an acetonitrile solution of the 16 priority

pollutant PAH's (see 7 above) plus 10-15

interferences. Issue Report

9. Procure and complete certification of indeno-

(1 ,2,3-cd)pyrene generator column SRM

10. If the three pesticides selected and studied

in 5 above are feasible for generator column

SRM's, procure and complete certification

11. Complete certification of the halocarbon

in Water SRM (based on results obtained in

6 above)

12/79

12/79

5/80

5/80

9/80

9/80

1/81

7/81

5/81
Selected Technical Accomplishments:

1 . Certification of Generator Columns for Polynuclear Aromatic

Hydrocarbons in Water (SRM 1644)

J. M. Brown-Thomas , W. E. May, W. J. Sonnefeld, R. A. Velapoldi,

P. A. White

Saturated solutions of polynuclear aromatic hydrocarbons (PAH) can be produced by passing distilled water through a column packed

with glass beads coated with the PAH compound of interest. The

aqueous solubility of the compound is a well-defined thermodynamic

quantity. Therefore, saturated aqueous solutions produced by this

column technique ("generator column") may also be defined as standard

solutions at a given temperature.

Generator columns for anthracene, benz(a)anthracene, and benzo(a)-

pyrene constitute SRM 1644. The columns were prepared commercially and

have been certified by two independent analytical techniques. The first

technique involves quantitative extraction of the PAH from the aqueous

stream by an "extractor column" packed with Ci 8 bonded phase, use of an acetonitrile-water effluent to transfer components from the extractor

column to an analytical Ci 8 column for separation of the analyte from

non-analyte components, and detection of the analyte by absorbance at

254 nm. The second technique uses a "standard addition" technique for

"on stream" analysis. The effluent from the generator column is mixed

with PAH standards dissolved in acetonitrile, and the resultant PAH in

the mixed solvent determined by fluorescence. Exemplary data from the

certification process are given in Table 1 . One equation is derived

from a compilation of similar data obtained from the two methods which

will allow the user to interpolate the certified concentration between

10°C and 30°C.

5
Table 1

Exemplary Results of Analysis Using Two Techniques for

Generator Column Aqueous Effluents.

Temperature

iSr

30

25

20

15

Anthracene

Concentration (ppb)

Technique 1 Technique 2

58.8

42.8

31.1

22.6

59.6

42.9

30.9

22.2

Temperature

30

25

20

15

Benz(a)anthracene

Concentration (ppb)

Technique 1 Technique 2

12.3

8.86

6.37

4.58

13.0

9.32

6.67

4.78

Temperature Sr

30

25

20

15

10

Benzo(a)pyrene

Concentration (ppb)

Technique""!* Technique 2

2.28 2.26

1.62 1.60

1.14 1.14

0.80 0.81

0.57 0.58

6
2. Determined Aqueous Solubilities and Chromatographic Characteristics

for Organic Compounds on the Priority Pollutant List

S. A. Wise, W. J. Bonnet

A knowledge of aqueous solubilities is the first step toward the

development of aqueous organic SRM's utilizing the generator column

technology. Since such data is sparse in the scientific literature,

solubility measurements have been made on several organic compounds to

date. The solubility data is displayed in table 2 along

with an assessment of feasibility of generator column SRM's for priority

pollutants.

3. Developed and Evaluated a Quenchofluorometric Detection System

for Chlorinated Pesticides

B. F. Howell, P. J. Logenbach, S. A. Wise

The quenching of fluorescence by pesticides has been observed, as noted in the literature by Lakowicz and Omann, who used this fact to

study pesticide uptake into membranes [Science, 197_, 465 (1977)]. This

quenching ability of certain pesticides has been used to formulate a method for the selective detection of pesticides as they elute from

an HPLC system.

The fluorescing probe used in the system developed was N-ethyl

carbazole. Initial fluorescence studies determined that p,p'-DDE,

lindane, endrin, p,p'-DDT, heptachlor, and a-hexachlorocyclohexane

quench the fluorescence of N-ethyl carbazole in cyclohexane. In these

studies the concentration of the pesticides was approximately 0.005M

and the N-ethyl carbazole, 3 x 10 6 M. The pesticide p,p'-DDE was found

to be the most effective quencher of those studied, and a preliminary

study showed its quenching to be linear from 0-200 ppm in 1 x 10~ 6 M

N-ethyl carbazole.

In adapting this method to an HPLC detection scheme, the N-ethyl

carbazole was dissolved directly in the mobile phase. The spectrometer

was set to observe its steady background fluorescence. Injection of a pesticide sample was detected as a decrease in the fluorescence.

A reverse phase HPLC system using a Ci 8 column and a mobile phase

of 85 percent (9.93 x 10~ 7 M N-ethyl carbazole in methanol), 15 percent

H 2 0 was found to separate endrin, p,p'-DDT, and p,p'-DDE. Injections on the order of 0.1 mg of these pesticides gave good response in the

fluorescence detection scheme, and could simultaneously be monitored

using a UV detector at 254 nm. It was found that the response observed

by fluorescence detection did vary with the concentration of N-ethyl

carbazole. The peak height for equal injections of p,p'-DDE varied

by a factor of 10 3

, when using N-ethyl carbazole ranging in concentration

from 1 x 1

0

-1

* M to 1 x 10” 8 M, with the largest peak being observed with the

most concentrated N-ethyl carbazole.

7
The significance of retention data can be demonstrated by using two

compounds in the Table 3 as examples, p,p'-DDD and heptachlor epoxide:

the retention times shown under Condition I (i.e., 2.3 and 2.4 respectively) for these two compounds indicate they could not be separated

under Condition I, but could be efficiently separated under Condition II (i.e., retention times of 6.8 and 4.0 respectively).

With N-ethyl carbazole present in the mobile phase, a constant

fluorescence signal is obtained. The presence of a chlorinated pesticide quenches this fluorescence, giving a peak in the negative direction. Data for comparing the limits of detection for eight pesticides by "fluorescence quenching" and by UV (254 nm) is shown in

Table 4-

8
Table 2

Solubility Values for Priority Pollutants and

"Generator Column SRM" Assessment

Hydrocarbons Solubility (ppb) Phenols

1 . acenaphthene 1 . phenol

2. naphtalene 31400 2. pentachlorophenol

3. acenaphthylene 3900 3. p-chloro-m-cresol

4. fluorene 1600 4. 2, 4, 6- tri methyl phenol

5. fluoanthene 206 5. 2-chlorophenol

6. pyrene 132 6. 2, 4-dimenthyl phenol

7. anthracene 43 7. 2,4-dichlorophenol

8. phenanthrene 1000 8. 1 ,2-dichlorophenol

9. benz(a)anthracene 9.8 9. 2-ni trophenol

10. chrysene 2.2 10. 4-ni trophenol

11. benzo(a)pyrene 1.2 11. 2, 4-dini trophenol

12. 3 ,4-benzof1 uoranthene 1.5 12. 4, 6-dini trophenol

13. 11 ,12-benzofluoranthene 3.2 13. 4 ,6-di ni tro-o-cresol

14. dibenzo(ah)anthracene <0.1

15. indeno(l , 2, 3-cd) pyrene 0.2 Suggestion

16. benzo(ghi )perylene 0.1

17. benzo( j )f1 uoranthene 2.5 All too soluble for genera

18. benzo(k)fl uoranthene 0.8 6column SRM. Maybe aqueous

19. benzene 1.8 x 10? solutions stable enough.

20. toluene 7.7 x 10°

Suggested Generator Columns

anthracene Because they cover the

benz(a)anthracene appropriate solubility

benz(a)pyrene range (i.e., ^50-0.1 ppb)

indenofl ,2,3-cd)pyrene

Pesticides & Metabolites Solubility (ppb)

1. aldrin 200, 17

2. dieldrin 250

3. chlordane 1850

4. 4,

4 '-DDT 1 5. 4

,4 ' -DDE 1 6. 4 ,4 1 -DDD 20

7. a-endosolfan 530

8. 3-endosulfan 280

9. endosulfan sulfate —

10. endrin 260

11. endrin aldehyde —

12. heptachlor —

13. heptachlor epoxide 350

14. toxaphene —

Suggested Generator Column Standards

aldrin

dieldrin

4,4'-DDD

9
Table 2 (cont.

)

Assessment of Priority Pollutant

Benzenes Solubility (ppb) PCB'si Solubili

1 . benzene 1.8 x 10? 1. Arochlor 1242 240

2. chlorobenzene 4.5 x 10c 2. Arochlor 1254 12

3. 1,2-dichlorobenzene 1.5 x 10c 3. Arochlor 1221

4. 1,3-dichlorobenzene 1.2 x 10 4. Arochlor 1232 ---

5. 1,4-dichlorobenzene 5. Arochlor 1248 54

6. 1 ,2,4= tri chlorobenzene 6. Arochlor 1260 3

1 . hexachlorobenzene c 7. Arochlor 1016 —

8. ethylbenzene 2.0 x 10

D

Suggested Generator Columns

Suggested Generator Columns

All too soluble

None because mixed generator

columns do not give saturated

solutions.

Nitrosamines Phthalate Esters Solubility (ppb)

N-ni trosodimethyl amine 1. bis(2-ethylhexyl ) phthalate 1.2 x 10

N-ni trosodi phenyl ami ne 2. butyl benzyl phthalate 1.1 x 10

N-ni trosodi -n-propyl amine 3. di-n-butyl phthalate

4. di-n-octyl phthalate

Chloroalkyl ethers

bis-(chloromethyl ) ether

bis-(2-chloroethyl ) ether

5. diethyl phthalate

6. dimethyl phthalate

1.2 x 10

2-chloroethyl vinyl ether

6

4

6

Suggested Generator Columns

All too soluble.

Miscellaneous

Solubility (ppb)

1. acrolein

2. acrylonitrile

3. benzidine

4. 2-chloronaphthalene

5. isophorone

5

6. toluene 7.3 x KT

It is NBS opinion that generator column SRMs

could not be prepared for any of these compounds.

10
Table 2 (cont .

)

Halocarbons

(all too soluble)

Li terature

Solubility (ppb)

1. methylene chloride

2. methyl chloride

3. methyl bromide

4. bromoform

5. dichlorobromomethane

6. trichlorofluoromethane

7. dichlorodifluoromethane

8. chi orodibromomethane

9. hexachlorobutadiene

10. chloroethane

11. 1 ,2-dichloroethane

12. 1 ,1 ,1-tri chloroethane

13. hexachloroethane

14. 1 ,1-dichloroethane

15. 1 ,1 ,2-trichloroethane

16. 1 ,1 ,2,2-tetrachloroethane

17. 1,1 -di chi oroethy 1 ene

18. 1 ,2-dichloroethylene

19. 1 ,2-dichloropropane

20. 1 ,2-dichloropropylene

21. vinyl chloride

22. hexachlorocyclopentadiene

23. a-BHC

24. 3-BHC

25. y-BHC

26. A-BHC

1.8 x 10

6

3.9 x 10

6

(3.7 x 10

6

NBS value)

11
Table 3

Retention Data for Pesticides

Conditions used:

I. Mobile Phase: 85% Me0H/H

2

0

Column: DuPont C^

g

II. Mobile Phase: Hexane

Column: Brownlee NH

2

Retention Time, cm

Conditions I Conditions II

p s p‘ -DDD 2.3 6.8

heptachlor epoxide 2.4 4.0

dieldrin 2.9 4.8

endrin 3.0 3.8

heptachlor 3.9 1.4

p 9 p

' “DDT 4.1 2.7

p,p' -DDE 5.4 1.5

aldrin 6.3 1.2

12
Table 4

Comparison of Detection Limits for Eight Pesticides

Mobile Phase: 80% (1 x 10~Sl N-ethyl carbazole in CH

3 CN)

Column: DuPont C-jg

Quenchofluorometric Detection UV Detection

(approx.) det'n limit, pg det'n limit, yg

p,p'-DDD 1.4 .012

heptachlor epoxide 4.8 .16

dieldrin 8.9 .093

endrin 4.0 .039

heptachlor 8.1 .19

p,p‘ -DDT .96 .015

p.p'-DDE .060 .0007

aldrin 6.7 .084

13
4. Liquid Chromatographic Retention Characteristics of Polycyclic

Aromatic Hydrocarbons - S. A. Wise and W. J. Bonnett

The retention characteristics of over 80 polycyclic aromatic

hydrocarbons (PAH) have been investigated on octadecylsilane (Ci 8 ) and

aminosilane (NH2 ) high-performance liquid chromatographic (HPLC) column

packing materials. These retention data are compiled in the form of

retention indices similar to the Kovats retention index system used in

gas chromatography.

Several different Ci 8 materials were investigated and were found

to vary in selectivity, and therefore have different retention indices

for some PAHs. These retention indices, although not unique for all

C 18 and NH 2 columns from different manufacturing processes, are useful

for the design of HPLC schemes for the analysis of complex mixtures of

PAHs. Such schemes have been employed for the determination of PAHs in

shale oil, air particulates, and marine sediments. These retention data

have also been correlated with the structure of the various PAHs to

elucidate the mechanism of HPLC retention of PAHs on Ci 8 and NH 2 materials. In addition, many of the PAHs studied are unavailable commer- cially; and therefore, these data will be valuable to other laboratories

that do not have these compounds.

5. Stability Study of Halohydrocarbons

F. Guenther

Solutions of seven halohydrocarbons at varying concentration levels

were prepared and stored both at room temperature and freezer temperature.

The stability of these solutions were checked after two months and again

after five months. The analytical method used to determine the concen- tration level (i.e. stability) in the halohydrocarbons was pentane extraction

(25mL) of 100 mL water, followed by on column injection into a 20 meter

SE-52 capillary column (1.0 ym film thickness) with electron capture detection. This method was chosen because of its higher reproducibility

in comparison to the purge and trap method and because of the short

analysis time and resolution obtainable with a capillary column.

It was determined that a relative standard deviation of approximately

5% was obtainable. These data were obtained using three separate extractions of prepared aqueous halocarbon solutions. Bromotrichloromethane

was used as the internal standard.

The purge and trap technique was also investigated, and showed a relative standard deviation in excess of 10%. Our studies utilized the

CDS 310 concentrator installed on a Varian 3700 GC. The analytical column

was a 3' 1% SP1000 on carbopack B.

Results of a five month stability study are shown in Table 5. The

first column gives the gravimetric concentrations of the starting material,

the second column is the results from the latest analysis and the last

column gives the average concentrations over the last nine analyses.

The problem with chloroform has not yet been identified. It could

be instability, inhomogeneity, or a measurement problem. Work is

proceeding to identify the problem. The rest of the compounds show a slight

14
Table 5

Concentration (ppb)

Avg. of

4/3/80 9/4/80 9 Runs (±SD)

Chloroform 76.2 56 + 1 —

Carbon tetrachloride 1.59 1.44 + .04 1.48 ± .05

Bromodi chi oromethane 3.88 3.59 + .03 3.6 ± .1

Dibromochloromethane 1.27 1.19 + .02 1.19 ± .03

Trichloroethene 0.920 0.81 + .01 0.83 ± .06

Tetrachloroethene 0.388 0.342 + .008 0.34 ± .04

Tribromomethane 0.247 0.219 + .008 0.22 ± .02

15
decline in concentration over the five months. This resulted from a new weighing technique, which corrected an earlier bias in the analytical

scheme. The averages, however, show a relative standard deviation of

3 percent for the higher concentrations to 10 percent for the lower

concentrations. This reflects the ampoule to ampoule homogeneity and

the analytical reproducibility. No differences have been identified

between the ampoules kept at room temperature and those kept in the

freezer.

A new set of ampoules were made up in September 1980, and will

be analyzed for stability in the coming months. This will resolve the

chloroform problem and the stability of the other compounds over the

short run. Analysis of the original ampoules will also continue to

resolve long term stability. An independent HPLC method of analysis is

also currently being developed.

6. Developed Alternate Proposal for Quality Assurance of PAH Measurement in Water

Goal :

Assist EPA in achieving and maintaining quality assurance in the

measurement of PAH in water by providing reference (rather than SRM's

which by definition require more stringent characterization often resulting

in longer certification/production periods) standards against which organics

in water measurements can be compared.

Scope:

1) Utilizing the generator column concept, NBS will provide a Standard Reference Material package for evaluating extraction efficiencies

of PAH from aqueous solution. We recommend that anthracene (45 ppb),

benz(a)anthracene (MO ppb), benzo(a)pyrene (-1 ppb) and indeno(l ,2,3-cd)-

pyrene (^0.2 ppb) be used to comprise this package.

2) NBS will also provide a reference standard for the chromatographic

analysis of the 16 PAH's on the EPA Priority Pollutant List. This solution

will be acetonitrile solution consisting of the 16 priority pollutant PAH's

plus 10-15 other PAH's that commonly appear in extracts from aqueous

effluents from oil shale processing and coal conversion plants.

3) NBS will develop a sequential HPLC analytical procedure with

spectrofluorimetric detection for the analysis of the 16 priority pollutant

PAH in the presence of other PAH interference such as those expected in

real-world samples. The chromatographic procedure proposed in EPA

Interim Method 610 allows for the separation of the 16 priority pollutant

PAH's one from the other, in simple synthetic solutions containing a limited number of interferences. That method, however, will yield

erroneous results when used for the analyses of more complex solutions

similar to those that will be derived from aqueous effluents from energy

conversion plants. For example on the Perkin Elmer column mandated by

method 610:

16
a) Several methyl chrysenes, and methyl benz(a)anthracenes

,

benzo(e)pyrene and perylene will all interfere with the

analysis of benzo(b)fl uoranthene .

b) 2-methyl anthracene will interfere with the analysis of fluoranthene .

c) 1 -methyfl uorene will interfere with the analysis of anthracene .

Mi les tones

:

1) Conduct a "round-robin" experiment with (1) a predetermined set

of generator columns and (2) an acetonitrile solution of the 16 priority

pollutant PAH.

2) Conduct a round-robin experiment with an acetonitrile solution

of the 16 priority pollutant PAH's plus 10-15 interferences.

3) Provide EMSL/CINC with a reference standard package consisting

of four generator columns; anthracene, benz(a)anthracene, benza(a)pyrene,

and indeno(l ,2,3-cd)pyrene and the organic solution of PAH's.

17
(2) Environmental Radioactivity Measurements

Participating Staff: Center for Radiation Research - J. M. R. Hutchinson,

J. R. Noyce, K. G. Inn, F. J. Schima, M. J. Unterweger, L. L. Lucas,

D. D. Hoppes, B. J. Coursey

Goal

Assist EPA in achieving and maintaining an optimum radiological

monitoring program to ensure quality assurance in the measurement

of environmental radioactive pollutants by providing measurement

methodology and radioactive SRM's and/or calibration standards.

Background

There is great public concern over the use of nuclear technologies

because of possible associated radioactive contamination of the

environment and Federal legislation (e.g. Clean Air Act, Clean

Water Act, Safe Drinking Water Act) requires monitoring of radioactive substances in the environment. The assessment of regional

and national effects of radionuclides on the environment depends

upon accurate and reliable radionuclidic measurements.

The regulators of radioactivity at the national level (e.g. EPA,

NRC) as well as state and local agencies have recognized the need

for an effective National Radioactivity Measurement System. Essential

to such a measurement system is the availability of certified

standard materials, test samples/sources and calibration services.

The NBS contributes to this measurement system by the production

and distribution of environmental radioactivity SRM's and test

samples, through tracecability programs with key laboratories and

by participating with organizations concerned with radioactivity

standards, methods, and data. The FY-1980 work plan addresses work

agreed upon by EPA/Las Vegas and NBS.

Scope

The NBS will

:

- Develop methods/techniques to produce environmental level

radioactivity standards in variety of matrices-aqueous , solid,

human tissue, soil

- Provide radioactive standards, test samples and/or calibration

services needed to support the EPA/Las Vegas traceability program

as well as overall radiological pollutant quality assurance

18
Milestones

1. Continue traceability study with EMSL/Las Vegas.

2. Develop standards for a TLD measurement assurance

program

3 . Evaluate monitoring methods for radium-228 and reDort.

4 . Prepare solution standard of plutonium-240 for use as

a radiochemical tracer in environmental monitoring.

5. Develop natural matrix reference material for radio-

-activity environmental monitoring programs.

6. Complete construction of a unique alpha spectrometer

system which will be used to measure low activity levels of

alpha emitting radionuclides.

7 . Develop mixed gamma-ray sources (SRM's) for the calibration

Of Ge(Li) spectrometers used in environmental monitoring.

8. Develop gaseous SRM's of Krypton-85 and Xenon-133 in

special geometries which can be used for calibrating

detectors used in monitoring reactor stack effluents.

9. Conduct international intercomparisons on iron-55, cobalt-57

cadmium-109, and barium-133 to improve the measurement

capability of these radionuclides

10 . Develop a mixed gamma-ray standard for calibration of

detection system which use "Marinelli Beaker" geometry in

monitoring programs.

rv one test/month

Indeterminate

5/80

7/80

9/80

3/80

8/80

8/80

7/80

10/80

19
1 . Traceability

Six samples will be submitted by NBS to EPA for measurement. EPA

will submit the results to NBS and, if the results agree. Certificates

of Traceability will be issued. Six EPA standard samples will be

submitted to NBS with the calibration values, and NBS will make

measurements to cross-check the EPA values. If appropriate, certificates

of Traceability will also be issued in these cases. If discrepancies

are revealed, EPA equipment can be recalibrated, using the information

on the traceability certificate, or their methods can be revised.

2. Develop Standards for TIP Program

1 33 Develop Xe in air mixtures at required levels of radioactivity

concentration. Mixing procedures will be developed. A reference

calibration will be performed with Ge(Li) spectrometers and the 2-

inch ionization chamber for the mixtures of Xenon immersion tank

sampling ampoules.

3. Monitoring Evaluation

The available methods for monitoring will be reviewed, through a survey of the literature, and evaluated. A report summarizing this

work with recommendations will be submitted to EPA.

4. Solution Standard of Pu-240

Pu-240 solutions standards will be proposed and calibrated by means

of a-particle counting. The preparation procedure includes examination

by a-particle and y-ray counting for impurities, multiple dilutions

and source preparation liquid scintillation, 0.8Tra and 0.1TM

and 2TM measurements, and preparation of certificates.

5. Natural -Matrix Standards

The collection, drying, grinding, sieving, bottling and initial

homogeneity testing of the lung, liver, and Rocky Flats East and

West samples will be accomplished this fiscal year.

6. A1 pha-parti cl e-Spectrometer System

The four chambers will be designed and constructed. The surfacebarrier detectors selected, and the vacuum systems completed so that the equipment will be operational by the middle of this

fiscal year.

20
7.

Long-lived Mixed Gamma-Ray Standards

The radioactivity components will be ordered and checked for

radioactive impurities by y-ray spectrometry, dilutions will be

made, sources prepared, calibrations performed using coincidence

counting, and ionization-chamber measurements made.

8. Noble Gas Standards Suitable for Calibration of Air Sampling

Charcoal Traps

Development will

3 proceed initially with tests of stability of

adsorption of xe with respect to typical air samplers and

charcoal traps over time periods ranging from 10 hrs. to 10

days. Calibration procedures for measuring activity before and

after exposure to the trap will be tested. This fiscal year goal

is to determine the accuracy level of activity of 'xe that can be attained using these traps.

9. International Intercomparisons

Four intercomparisons are planned, Fe-55, Co-57, Cd-109, Ba-133.

Radioactive materials are purchased, solutions are prepared and

calibrations performed. The solutions are distributed to participating laboratories who return their measured values which are collated and compared. If the values disagree, proposals are considered for remedial action.

10 . Marinelli-Beaker Calibrations

Marinelli-Beaker sources, prepared as described by an IEEE

standard, will be submitted to NBS. A similar beaker, containing the

same radionuclides in known amounts, will be prepared at NBS. The

unknown will be calibrated by comparison with the NBS standard

using a Ge (Li )-spectrometer.

21
Selected Technical Accomplishments

1 . Provided Services to EPA/Las Vegas Under the Measurement Traceabi 1 i t.y Program

Traceability (or reliability) of radioactivity measurements is

required or recommended under various regulation, agreements, regulatory

guides, licensing provision, written standards and recommended practices.

Simply stated, traceability to NBS is established when an outside laboratory (in this case EPA/LV Quality Assurance Branch) correctly mea- sures test samples provided by NBS, or when NBS measures standard sam- ples provided by an outside laboratory and the analytical results agree

within the assigned calibration limits. Some activities under the

EPA/NBS measurement traceability program are shown below:

- Reference Radionuclide samples sent to EPA/LV

° Phosphorous-32

° Scandium-46

° Promethium-147

° Cesium- 134

° Nickel -63

° Cobalt-57

- Completed measurement of EPA/LV standards sent to NBS

° Chromium-51

- Evaluated results and completed ratios of results reported by

EPA/LV to NBS on test samples

Radionuclide QAD/NBS

Scandium-46 0.995

Cesium- 134 0.996

Americium-241 0.995

Cobalt-58 0.961

Plutonium-238 1.000

Cobal t-57 1.027

Nickel-63 1.044

22
TABLE 6

Radioactivity Concentrations of l5i XE

Samp!

e

Number

Time of

Sample

[hr: mi n]

Elapsed

Time

[mi n j

Radi oactivi ty

Concentration R(i)

Rati o R(i)/R(l)

lonizati on Chamber*

[mi n~* J

1 10:53 0 9.67 ± 0.26 2.000 ± 0.027 ' r. < 2

2 11:05 12 8.96 ± 0.27 0.967 i 0.028 f 3 .. 5

3 11:46 54 9.45 ± 0.26 0.977 i .026 16.6

4 13:22 149 8.27 ± 0.22 0.855 i .022 22.5

5 13:37 164 7.80 i 0.15 0.807 ± .015 22.6

- 13:40 167 GLOVE BOX OPENED/FLUSHED

- 13:49 176 — 15.0

- 14:03 190 -- — 13.7

14:33 220 -- -- 11.7

*Backgrou nd reading prior to e release v/as 0.1 min" 1

23
2. Evaluated Monitoring Methods for Radium-228 and Issued a Report

The technical literature from 1967 through May 1980 was reviewed

for methods related to radium-228 assays in water. The methods were evaluated for their suitability as potential EPA reference methods for

drinking water assays. It was suggested the present EPA reference

method (Krieger, 1975) be retained but improved and a second method

(McCurdy & Mellar, 1979), which employs beta-gamma coincidence counting,

be added. Included in the report is a table that lists the principal

features of 17 methods for radium-228 assays.

3. Developed a Sampling Procedure for Calibration of 133 Xe-Air Mixtures

A sampling procedure has been devised to determine exposures to

beta-particle emissions of TLD's immersed in 133 Xe-air mixtures. The

procedure utilizes an NBS (almost-spherical ) glass ampoule, with a vacuum-cup stopcock attached as a sample. A Ge(Li) detector system has

been calibrated for y-ray efficiency with this source configuration.

133 Xe was released into a glove box used as an immersion chamber and

samples of the 133 Xe air mixtures were taken in the sample bottles.

Procedure

Several ampoules were evacuated, stopcocks closed and placed inside

a glove box which had been prepared as an immersion chamber. A fan was placed inside the glove box to continously mix and move the 133 Xe and

air mixture. The sampling ampoules and the Mylar-window ionization

chamber were sealed in the glove box. Approximately 115 microcuries of

133 Xe gas were released inside the glove box, which was estimated to

have a volume of 312 li ters , giving a calculated initial radioactivi ty

concentration of 13.6 s"

1 cm” 3 or 360 picocuries/cm3

. The 133 Xe and air

were mixed for 15 minutes, at which time constant readings of the ionization chamber were observed. The glove box remained sealed for 240

minutes. At various times, five samples were open for about 5 seconds

and then closed. As these labeled ampoules were filled with the 133 Xeair mixture, the time and ionization chamber reading were recorded. The

glove box was opened and flushed with room air through an 1100m 3 /min

hood to a stack.

The labeled ampoules subsequently were assayed by measuring the 81-keV

gamma-ray-emission rate with a calibrated Ge(Li) detector system.

Corrections were made for the ampoule-wall thickness. Activity was calculated using a value of 0.371 for the probability per decay for the

81-keV gamma ray in 133 Xe decay.

Table 6 lists the radioactivity concentrations of 133 Xe in the

glove-box air space at the time that each sampler was filled and resealed.

Also the ratio of the radioactivity concentration at the time of sampling

to the appropriately decayed radioactivity concentration of the first

24
sample is given. Lastly, the reading, at the time of sampling, of the

Mylar-window ionization chamber is listed. The errors shown in the

Table are the random uncertainties due to counting. These range from 2 to 3 percent depending on the length of measurement time for each ampoule.

Inspection of the two right-hand columns of the table illustrate

some surprising results. The ionization-chamber readings increased with

immersion time while the radioactivity concentration decreased with

immersion time. The first phenomenon is attributed to

133 Xe contamination of the Mylar-window ionization chamber which is borne out by the

slow rise in the ionization-chamber readings during immersion followed

by a slow reduction in the readings after the 133 Xe-air atmosphere was

removed. The ionization-chamber after 3 days was equal to the original

background reading. The second phenomenon is attributed to the loss of

133 Xe inventory inside the glove box by either or both, leaks and adsorption on the rubber seals and gloves and the ionization chamber

itself.

This work demonstrates a potential problem in the monitoring of

133 Xe in air. The 133 Xe concentration was measured as decreasing some

20% in 225 minutes while a portable monitor indicated an 85% increase

over the same period. 133 Xe distributions in small enclosures is not

predictable.

4. Seven Natural Matrix Materials have been Dried, Ground, Homogenized

and Bottled

See Table 7 for tabular status of the Natural Matrix Materials.

Preliminary assays have also been performed on five of these material s- Rocky Flats Soil E (RFSE), Rocky Flats Soil West (RFSW), Columbia River

Sediment (CRS) and Gyttya. Table 8 shows the current status of assay

for five materials.

25
Table 7

Status of Environmentally Calibrated Material

Rocky Flats

Sol 1 -West Rocky Flats Soil-East

Peruvian

Soil Columbia River

Sediments Gvttla Human Liver

Human

Lunq Remarks

Collected / / / Several hundred kilograms

Dried / /

Freeze Dried

/

Freeze Dried

/

Freeze Dried 50 kg

/

Freeze

Dried

17 kg

Air dried or freeze dried at

< 100°F shelf temperature

Milled /

* * /

* / /* **

Average Particle Diameter ~ 5y milled by pancake air jet mill with internal classification Partially milled by cryogenic

hammermlll but > 30S + 200 mesh

Blended

109 kg 132 kg 50 kg 190 kg

/

59 kg

"V" blender used w/intensifler

bar blended for 30 min.

Nal Homogenei ty

)e termination

/ / / / / Inhomogeneity <0.31 (3s)

Preliminary

Assay / / / /

Ge ( L 1 ) spectroscopy & radiochemistry

Bottled / /

Semi -Quantitative

Elemental Determination / / / / / Measurements by emission spectros- copy

Assay

26
Table 8

STATES OF ASSAY OF NATURAL MATRIX STANDARDS (10/80)

a 3 Y

Energy calibration + N/A +

Efficiency calibration /

Background / - N/A

Chemistry / - N/A

Source preparation / - +

Blanks / - +

Homogeneity /

Count times 2 weeks 2 months 1 week

Activity levels 2 pCi/sample pCi/sample pCi/sample

Data analysis / /

Equipment preparation / / +

Equipment instability / <1% + <0.3%

Samples in the works RFSE RFSE

RFSW

CRS

GYTTJA

+ = / =

blank space =

completed work

partially completed work

work initiated

work yet to be initiated

27
U.S. Department of Commerce

Juanita Kreps y?

National Bureau^ of 1Standards

Ernest ^mblter, Director

Rational ^wreau of Standards

Report of Traceability Measurement by

QUALITY ASSURANCE DIVISION

U.S. ENVIRONMENTAL PROTECTION AGENCY

LAS VEGAS, NEVADA

on an NBS Reference Sample of Undisclosed Value of

CESIUM-134

This is to report that on the basis of nine independent measurements on a solution of cesium-134 with a known, but undisclosed, radioactivity concentration on January 1, 1980, of

on January 1, 1980.

The uncertainty in the QAD value, 3.0 percent, is the linear sum of 2.0 percent,

which is half the 99-percent confidence interval of the mean of the $-y coincidence-counting determinations, and 1.0 percent v which is the linear sum of

the estimated upper limits of conceivable systematic errors.

The QAD value differs from the NBS value by 0.4 percent. This result demonstrates the traceability of QAD to NBS, for this measurement, to within five

percent as specified in the appendix, "Traceability Studies", of the EPA-NBS

interagency agreement of April 1976.

The attached sheet provides supplemental information about this cesium-134

reference sample.

*1.426 x 104 s-ig' 1 ± 1.7%*,

the Quality Assurance Division (QAD) reported a value of

1.42 x 104 s-ig" 1 ± 3.0%

ni y'or + nv'

W.B. Mann, Principal Scientist

Radioactivity Group

Center for Radiation Research

May 21 , 1980

Attachment 28
SUPPLEMENTAL INFORMATION

ABOUT

CESIUM-134 REFERENCE SAMPLE

OF

JANUARY 1980

This reference sample consisted of cesium-134 in 4.308 grams of carrier solution

in a flame-sealed, borosil icate-glass ampoule. The solution contained 40 micrograms of stable cesium per gram of 1.9 molar hydrochloric acid. The reference

sample was prepared by a gravimetric dilution of a master solution.

The radioactivity concentration of the master solution was measured using the

National Bureau of Standards pressurized "4-rr"Y ionization chamber that had

previously been calibrated with a cesium-134 standard in terms of a radium-226

reference source. A half life of 2.062 ± 0.005 years was used to calculate the

cesium-134 decay from the date of calibration to the date of the QAD value

(NCRP Report No. 58, App. A, National Council on Radiation Protection and

Measurements, Washington, 1978).

The uncertainty in the cesium-134 radioactivity concentration of this reference

source, 1.7 percent, is the linear sum of 0.43 percent, which is the 99-percent

confidence limit of the mean of ten ionization-chamber measurements, and 1.27

percent, which is the linear sum of the estimated upper limits of conceivable

systematic errors. The estimated upper limits are 1.1 4 percent in the ionization-chamber calibration, 0.03 percent in the computation of decay, and 0.1

percent in the weighings associated with the preparation of the reference source.

The master solution was examined for gamma-ray-emitting impurities with a Ge(Li)-

spectrometer system over the energy region of 90 to 1900 keV, and no impurities

were observed. The detection limits for impurity photons can be expressed as a percentage of the emission rate of the 604-keV gamma ray emitted in the decay

|i of cesium-134. The limits are 0.1 percent for photons with energies less than

790 keV and 0.01 percent for photons with energies greater than 807 keV, provided

that the impurity photons are separated by 5 keV or more in energy from photons

of equal or greater intensity emitted in the decay of cesium-134.

29
I'.S. Department of Commerce

Juanita Kreps

Secretary

Naiional Bureau of Standards

Ernest Ambler. Director

^National Purest! of J^iantfartta

Report of Traceability Measurement by

Radiological and Envi ronmental Sciences Laboratory

U.S. Department of Energy

Idaho Falls, Idaho

on an NBS Reference Sample of Undisclosed Value of

SCANDIUM-46

This is to report that on the basis of 12 independent measurements on a solution of

scandium-46 with a known, but undisclosed, 889.25-keV gamma-ray emission rate per

gram at 1400 EST April 1, 1980, of

*1.348 x IQ4 ys” 1 g

-1 ± 0.94%*,

the Radiological and Environmental Sciences Laboratory (RESL) reported a value of

1.39 x 104 ys-V1 ±4.5%

at 1400 EST April 1, 1980.

The uncertainty in the RESL value, 4.5 percent, is the linear sum of 0.9 percent,

which is half the 99-percent confidence interval of the mean of the germanium-spectrometer measurements, and 3.6 percent, which is the linear sum of the estimated

upper limits of conceivable systematic errors.

The RESL value differs from the NBS value by 3.1 percent. This result demonstrates

the traceability of RESL to NBS, for this measurement, to within five percent as specified in the document "Testing of NRC Reference Laboratory" of April 1976, as amended.

The attached sheet provides supplemental information about this scandium-46 reference

samp! e.

For the Director,

W.B. Mann, Principal Scientist

Radioactivity Group

Center for Radiation Research

August, 1980

Attachment

30
SUPPLEMENTAL INFORMATION

ABOUT

SCANDIUM-46 REFERENCE SAMPLE

OF

JANUARY 1980

This reference sample consisted of scandium-46 in 4.929 grams of carrier solution in

a flame-sealed, borosili cate-glass ampoule. The solution contained 24 micrograms of

stable scandium per gram of 1 M hydrochloric acid.

The sample was a portion of a solution whose radioactivity concentration was measured

in the NBS 4 tt 3 (LS)-y anticoincidence system using the efficiency-extrapolation method.

A half life of 83.83 0.02 days was used to calculate the scandium-46 decay from the

time of calibration to the time of the RESL value (NCRP Report No. 58, App. A, National

Council on Radiation Protection and Measurements, Washington, 1978). The 889.25-keV

gamma-ray emission-rate per gram is essentially equal to the radioacti vity concentration (Py = 0.999840 ± 0.000010, ibid .).

The uncertainty in the 889.25-keV gamma-ray emission-rate per gram, O .94 percent, is

the linear sum of 0.66 percent, which is half the 99-percent confidence interval of

the mean for six independent calibration measurements, and 0 . 2g percent, which is the

linear sum of the estimated upper limits of conceivable systematic errors. The

estimated upper limits of the systematic errors are 0.1 percent in the weighings of

the calibration sources, 0 .I 5 percent in the 4tt3(LS)-y measurements, and 0.03 percent

in the calculation for decay.

The scandium-46 was examined for gamma-ray-emitting impurities with a Ge(Li)-spectrometer system over the energy region of 90 to 1900 keV, and no impurities were observed.

The detection limits for impurity photons can be expressed as a percentage of the

emission rate of the 1120.5-keV gamma ray emitted in the decay of scandium-46. The

limits are 0.1 percent for photons with energies less than 1115 keV (provided that the

impurity photons are separated by more than 5 keV in energy from the 889.25-keV photon

emitted in the decay of scandium-46), and 0.01 percent for photons with energies

greater than 1126 keV.
U.S. Department of Commerce

Juanita Kreps

Na rds

Rational of Standards

Report of Traceability Measurement by

Quality Assurance Division

U.S. Environmental Protection Agency

Las Vegas, Nevada

on an NBS Reference Sample of Undisclosed Value of

AMERICIUM-241

This is to report that on the basis of eight measurements with a 2tt gas-flow

proportional counter on point sources prepared from a solution of americium-241

having a known, but undisclosed, radioactivity concentration on April 22, 1980 of

on April 22, 1980.

The uncertainty in the QAP value, 3.4 percent, is the linear sum of 1.9 percent, which

is half the 99-percent confidence interval of the mean of the proportional-counter

measurements, and 1.5 percent, which is the linear sum of the estimated upper limits

of conceivable systematic errors.

The QAD value differed from the NBS value by 0.5 percent. This result demonstrates

traceability of QAD to NBS, for this measurement, to within five percent as specified in the appendix Traceability Studies of the EPA-NBS interagency agreement of

April 1976, as amended.

The attached sheet provides supplemental information about this americium-241 reference

source.

*913.9 s'V1 ± 1.3%*,

the Quality Assurance Division (QAD) reported a value of

909 s'V1 ± 3.4%

For the Director,

W. B. Mann, Principal Scientist

Radioactivity Group

Center for Radiation Research

June 12, 1980

Attachment 32
SUPPLEMENTAL INFORMATION

about

A NBS REFERENCE SAMPLE OF

AMERICIUM-241

This reference sample consisted of americium-241 in 3.521 g of approximately

5 M nitric acid in a flame-sealed, borosil icate-glass ampoule, and was a portion of a master solution which was calibrated by liquid-scintillation

counting of five sources that had been quantitatively prepared from the master

solution.

The master solution was examined for photon-emitting impurities with a calibrated germanium spectrometer system and none was found. The detection limit

for impurity photons may be expressed as a percentage of the emission rate of

the 60-keV gamma ray emitted in the decay of americium-241. The limit is 0.01

percent for photons with energies greater than 65 keV, provided that the impurity photons are separated in energy by 5 keV or more from photons of equal or greater intensity emitted in the decay of americium-241.

The uncertainty in the radioactivity concentration of the reference sample,

1.3 percent, is the linear sum of 0.6 percent, which is half the 99-percent

confidence interval of the mean of the liquid-scintillation measurements, and

0.7 percent, which is the linear sum of the estimated upper limits of conceivable systematic errors. The estimated upper limits are: 0.4 percent in the

wall-absorption effects of the liquid-scintillation vials, 0.1 percent in the

timing of the measurements, 0.1 percent for dead time during the measurements,

and 0.1 percent in the preparation of the counting sources, including uncertainties in the weighings.

A half life of 433 ± 2 y (D. C. Kocher, 0RNL/NUREG/TM-1 02 , August 1977) was used

in the calculation for decay from the date of calibration by NBS (May 23, 1979)

to the date of the measurements by QAD (April 22, 1980).
form NBS-44S

(REV. 12-65)

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

WASHINGTON, D.C. 20234

REPORT OF CALIBRATION

on one solution of

CHROMIUM-51

submitted by

Quality Assurance Division

U.S. Environmental Protection Agency

Las Vegas, Nevada

One flame-sealed ampoule, said to contain chromium-51 in aqueous solution*

was submitted for calibration as part of the Measurement Traceability Program for fiscal year 1980 between the National Bureau of Standards (NBS)

and the Environmental Protection Agency (EPA).

The ampoule was opened and the solution gravimetrical ly transferred to an NBS standard ampoule. Several drops of water were added in order to make

a total mass of five grams, and the ampoule was then flame sealed.

The gamma-ray-emission rate of the solution at 320 keV was measured, on five different dates over a three-week period, with the ampoule positioned

26 cm from a Ge (Li) detector with a known detection efficiency. Using a gamma-ray probability per decay of 0.0980 ± 0.0003( a ), the radioactivity

concentration of chromium-51 in the undiluted EPA solution was

*9.14 x 10 3 s -1

g

_1 ± 5.5%*

at 0700 EST December 13, 1979.

The uncertainty in the NBS value, 5.5 percent, is the linear sum of 3.0 percent, which is half the 99-percent confidence interval of the mean of the

five gamma-ray emission-rate measurements, and 2.5 percent, which is the linear

sum of the estimated upper limits of conceivable systematic errors. These

estimated upper limits are: 1.0 percent in the calibration of the germaniumdetector efficiency at 320 keV with a point source; 0.5 percent in the ratio

of detection efficiency for an ampoule source to that for a point source; 0.3

percent in the positioning of ampoules for measurement and differences in

geometry among ampoules; 0.2 percent for changes in detector efficiency over

the period of the measurements; 0.3 percent in the gamma-ray probability per

decay; and 0.2 percent in the calculations for decay, based on a half life of

27.704 ± 0.004 d^).

34
- 2 -

The EPA reported a radioactivity concentration of chromium-51 for this solution

of

9.00 x 10 3 s^g’ 1 ± 9.8%

at 0700 EST December 13, 1979. The uncertainty in the EPA value, 9.8 percent,

is the linear sum of 4.6 percent, which is half the 99-percent confidence

interval of the mean of the germanium-spectrometer measurements on nine samples,

and 5.2 percent, which is the linear sum of the estimated upper limits of known

systematic errors.

The EPA value differs from the NBS value by 1.5 percent. This result demonstrates

the traceability of EPA to NBS, for this measurement, to within five percent as stated in the appendix, Traceability Studies3 of the EPA-NBS interagervcy agreement of April 1976, as amended.

June 12, 1980

For the Director,

Oa

W. B. Mann, Principal Scientist

Radioactivity Group

Center for Radiation Research

NBS value.

^

NCRP Report No. 58, National Council on Radiation Protection and Measurements, Washington, D.C. (1978).

35

6

'
(3) Hazardous Waste: Sludge Characterization and Fly Ash

Characterization

Participants: Center for Analytical Chemistry - R. W. Burke,

B. I. Diamonds tone

Background

With the passage of the Resource Conservation and Recovery Act in

1976, Congress mandated that EPA establish a set of regulations by

April 1978 regarding the identificaiton, transportation, and disposal

of hazardous waste materials. EPA subsequently defined eight

characteristics for waste materials, any one of which would classify a waste material as hazardous. One of these characteristics,

EP toxicity, EPA has chosen to relate to the amounts of certain

priority inorganic and organic pollutants which are leached from

the wastes under a set of empirical extraction conditions.

Early in FY80, NBS (through the Office of Recycled Materials)

entered into an interagency agreement with EPA to evaluate the

several extraction procedures that were being considered as ac- ceptable tests for the identification of hazardous wastes. A copy

of this agreement (EPA 79D-X0810) can be found in the Appendix,

this report (pp. 257). A detailed work statement for this project

which was submitted to (and accepted by) EPA/Las Vegas is given in

(C) of this section. The resources ($11 OK) provided to the NBS

Office of Environmental Measurement through the EPA Pass-Through

program were in support of the objectives and milestones of this

large hazardous waste effort.

36
Scope/Milestones

(Submitted by

Office of Recycled Materials/Center for Analytical Chemistry to

EPA/Las Vegas)

Task I : Initiate and complete studies on a representative "hazardous"

fly ash as provided or recommended by EPA. These studies will result in

the development and issuance of a quality assurance standard for use in

EPA's intercomparison and laboratory accreditation programs. The

outputs of this task are:

A. Collect, blend, sieve, and homogenize a minimum of 250 kg of

the chosen fly ash.

B. Establish the chemical composition of this fly ash by using

existing NBS standards and comparative instrumental techniques.

C. Determine the extraction and analysis variabilities on the

leachates derived from this fly ash using the proposed EP and

the extractor built under the FY 79 EPA project.

D. Develop reference leachate data using the EP for the eight

priority inorganic pollutants, i.e. As, Ba, Cd, Cr, Pb, Hg,

Se, and Ag.

E. Package, label and deliver to EPA 500 units, each containing

105 grams, of the quality assurance fly ash standard.

Task II : Initiate studies on a sludge or sludge-like material as chosen

in concert with EPA for possible future (FY 81) issuance as a more complex

type of quality assurance standard. The outputs of this task include:

A. Obtain profile leachate data for priority inorganic on 3-5

candidate sludges recommended or provided by EPA.

*B. Survey the EP leachates obtained in step A for selected organics

on the priority pollutant list, i.e. chlorinated compounds,

phenols, polynuclear aromatics, etc. (Level of effort--$30K)

C. Study sampling, packaging, and storing techniques on the most

promising sludge.

D. If step C is successful, carry out detailed stability and

homogeneity studies on 200-400 kg quantity of the selected

sludge.

E. Establish the inorganic chemical composition of this sludge by

use of comparative instrumental techniques and available NBS

standards

.

F. Obtain leachate data for the priority inorganic pollutants using

the proposed EP and the extractor built under the FY 79 EPA

project.

37
Project Costs : The above tasks are listed in priority order and need to

Be carried in that order. The anticipated costs for each task is as follows:

Task 1 $ 75,000

Task II 210,000

Total $285,000

^Sub-task B, Task II, will be accomplished by the Organic Analytical Research

Division, depending upon analytical committment and the availability of the

indicated funds. All other sub- tasks will be accomplished by the Inorganic

Analytical Research Division.

38
Selected Technical Accomplishments

1 . Characterization of Potentially Hazardous Waste-Development of

Rotary Extractor and Quality Assurance Standards

In order for NBS to fulfill its obligation to EPA, it was necessary

to develop a procedure which would reproducibly extract the Teachable

priority pollutants from the waste material. Although a number of

extraction techniques are presently in use, the results of various

interlaboratory studies indicated that variations in concentrations of

orders of magnitude for the priority pollutants are not uncommon. Although this can be a result of poor analytical technique and/or sample

inhomogeneity, the possibility of poor extractor designs must also be

considered. In fact, data presented at a number of ASTM meetings in

which several members of NBS staff participated, clearly indicated that

the reproducibility of the extraction procedures was extremely poor.

Thus, in order for meaningful measurements to be made on an interlaboratory basis, an improved extractor design was of paramount importance.

Based on our interpretation of the EPA Federal Guidelines, a model

extractor was designed which allowed four samples to be run simultaneously in 2-liter containers. The sample containers were tumbled endover-end at 29 rpm permitting intimate contact between the waste and the

extracting solutions. Although extensive testing of this rotary ex- tractor at NBS is incomplete, EPA has chosen to include this design as an acceptable model in the latest Federal guidelines. Presently,

studies are in progress to evaluate the efficiency and abrasion characteristics of this design on selected wastes. An illustration of this

rotating extractor is shown in figure 1 .

Currently, NBS is in the process of providing to EPA a number of

units of representative waste material which will be a fly ash that is

totally characterized for chemical composition using NBS standards.

Information will also be provided on the concentrations of the priority

pollutants which can be leached from the material under specific ex- traction conditions. In addition, NBS is initiating studies on some sludge materials to be used as more complex quality assurance standards.

Work in this area is expected to continue in FY81

.

39
I

40

Figure

1.

NBS-designed

four-unit

rotary

extractn
(4) Energy-Related Organic and Inorganic Water Standards Development

Participating Staff: Center for Analytical Chemistry

Background

In order to assess the total effects of energy development upon our environment, an effective multi -media monitoring and measurement

assurance system must be maintained. Development of a compatible

data base to determine the source, transport, and fate of environmental

pollutants is a necessity if rational and logical decisions are to

prevail in planning the types, pattern, and magnitude of energy

developments which are environmentally acceptable. Since the

western states are already or will be seriously impacted by present

or projected energy-related development activities, the Western

Energy/Environment Monitoring Study (WEEMS) was initiated to provide

an accurate multi -media data base keyed to air and water pollutants

and surface effects associated with projected western energy re- source developments.

Scope

The activities in this project focus on the development of energy

related water pollutant SRM's for conventional fossil fuel mining

and combustion and SRM's for advanced fossil fuel technologies.

The SRM's developed in this project will be provided to EMSL/

Cincinnati in support of the WEEMS project as well as in support of

EPA quality assurance programs. Representative milestones for the

standards development of the EPA/NBS E/E Accomplishment Plan for

FY-1980 included:

° Development of SRM's or reference standards

(characterized for organics and inorganics) for

measuring and monitoring water quality of

the western water resources with particular

emphasis on the Northern Great Plains area

and the San Juan Basin.

° Assessment/feasibility of producing specific

SRM' s/reference standards for calibration of

organics in water measurement methods for

pollutants associated with existing energy

technologies.

° Development of SRM's for use in methodology

assessment, method calibration, and monitoring

of water pollutants associated with emerging

technologies. Included in this milestone is

the need for development of environmental

measurement methods capable of measuring trace

toxic substances in complex matrices created

by new energy technologies to support the

establishment of effective monitoring systems.

41
Selected Technical Highlights

1. First Natural Matrix Trace Orqanic SRM Issued for Shale Oil

(SRM 1580)

J.M. Brown-Thomas , S.N. Chesler, F.R. Guenther, H.S. Hertz,

L.R. Hilpert, P.L. Konash, W.E.May, R.M. Parris, K.L. Richie,

S.A. Wise

The Center for Analytical Chemistry have in the past conducted

several collaborative studies aimed at assessing the accuracy of data

obtained from trace organic analytical methodologies. The results of a recent study involving the determination of specified phenols, polynuclear aromatic hydrocarbons , and N-heterocyclics in a shale oil sample

by several laboratories revealed large systematic biases among laboratories. One method for enhancing the accuracy of analytical mea- surements is the use of suitable quality assurance standards or Standard

Reference Materials (SRM's). However, until now, SRM's for environmental

trace organic analyses were nonexistent due to the lack of analytical

methodologies necessary for certification.

Over the past few years, analytical methodologies have been developed and used to certify the first natural matrix SRM for trace- level

organic constituents, Organics in Shale Oil, SRM 1580. The quantitation

of individual compounds in the complex shale oil matrix necessitated the use of mul ti-dimensional chromatographic procedures, i.e., gas or liquid

chromatography on two columns of different selectivity and/or extremely

selective detection methods.

Three different methods of sample preparation were used prior to

analysis: simple dilution of the shale oil with methylene chloride (or

other suitable solvent); aci d/base extraction to isolate acidic, basic,

and neutral components; and a high-performance liquid chromatographic

fractionation. Two of the following techniques were employed to determine the certified values for the organic compounds in shale oil:

capillary gas chromatography (GC) , gas chromatography/mass spectrometry

(GC/MS) with single ion (monitoring) for selective detection, and high - performance liquid chromatography (HPLC) with selective fluorescence

detection. All GC/MS analyses used the standard addition method for

quantitation. The GC and HPLC analyses employed either internal standard, external standard, or standard addition methods. The excellent

comparability of the values determined by these different analytical

methods is illustrated in Table 9. Table TO lists values for other

compounds determined by only one technique. These values will appear on the SRM certificate for information only. The methods developed for the

certification of this SRM are applicable to the determination of similar

compounds in other complex natural matrices. Standard Reference Material

1580, Organics in Shale Oil, is intended primarily for evaulating the

reliability of analytical methods used for the determination of trace

level polynuclear aromatic hydrocarbons, phenols, and nitrogen heterocyclic compounds in shale oil, coal-derived liquids, or petroleum products.

In addition, this SRM may be used as a surrogate standard for any com- plex environmental extract containing classes of compounds for which the

SRM is certified.

42
Table

9.

Summary

of

Results

for

Organic

Compounds

in

Shale

Oil

Determined

by

Two

Independent

Techniques.

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Table 10. Summary of Results for Organic Compounds in Shale Oil

Determined by One Technique.

Sample Preparation Analytical Concentration

Compound Technique Technique (yg/g)

benzo(k)fluoranthene HPLC HPLC 13

phenanthridine HPLC HPLC 45

m-cresol Acid/Base Extraction GC 330

p-cresol Acid/Base Extraction GC 270

2 ,4-di men thyl phenol Acid/Base Extraction GC 380

2, 5-dimethyl phenol Acid/Base Extraction GC 320

2 ,5 ,6- tri methyl phenol HPLC GC/MS 360

2 ,4 ,6- tri methyl phenol HPLC GC/MS 120

a. Shale Oil Round Robin :

Many laboratories are currently involved in the quantitative

analysis of individual toxic organic compounds in alternate fuels and

energy effluents. For many of these environmental analyses there is

little knowledge of the comparability of data from different laboratories, and in most cases probably little knowledge of intralaboratory

precision. To gain insight on this matter aliquots of the shale oil

sample were sent to six laboratories currently involved in characterizing alternate fuels. The labs were requested to determine the con- centrations of selected compounds in the shale oil. The results of

this limited inter-laboratory exercise are presented in Table 11. The

scatter of the results indicates the variability of state-of-the-art

quantitative analyses for individual compounds in a complex matrix. It

also stresses the need for an SRM such as the shale oil which laboratories can use to guage the accuracy of their analytical methods.

Table 11. Interlaboratory comparison of results of shale oil analyses

(ppm).

Compound NBS

a

2 3 4 5 6 7

pyrene 107 155 360 150 168 212 141

fluoranthene 61 102 220 80 108 104 112

phenol 395 392 180 - - - 399

o-cresol 338 350 150 - - - 381

2 ,4 ,6- tri methyl pyri di ne 1060 468 460 - 950 - 1092

a Results reported by NBS represent the mean of values obtained by GC,

GC/MS, and HPLC.

44
2. GC/MS Analysis of Aqueous Effluents from Coal Conversion Processes

L. R. Hilpert, B. F. Howel , K. L. Richie

Analysis of aqueous effluents from coal conversion processes has

been initiated with the receipt of our first effluent samples. Two

aqueous effluents were received from the Pittsburgh £• Midway Coal Mining

Co. Solvent Refined Coal (SRC) Pilot Plant:, a BioUnit effluent and a Plant effluent. The BioUnit effluent is filtered through sand and charcoal, and then mixed with solidification belt cooling water to generate

the Plant effluent.

A simple extraction procedure was used to isolate neutral, acidic,

and basic fractions from the samples. Neutral fractions were obtained by

extracting 50 mL of the aqueous effluent with 25 mL CH 2 C1 2

. Two additional 50 mL aliquots of the effluents were adjusted to pH 1 with H 2 S0 4 and to pH 13 with concentrated KOH, respectively and extracted with 25 mL

of CH2 Cl 2 to generate the acidic and basic fractions.

The above fractions (for both the BioUnit and Plant effluents) were

analyzed by GC/MS on a 30 M SP-1000 high resolution capillary column.

Total ion chromatograms for the acidic, basic, and neutral fractions from

the BioUnit effluent are shown in Figures 2, 3 and4. Tentative peak

identifications were based on a comparison of the mass spectra generated

during the GC/MS analysis with a library of mass spectra. The chromatograms for the neutral and basic extracts show the same compounds (a series

of n-alkanes ^C 13 -C2 o» substituted pyridines and tetrahydroquinol ines) in

the same relative amounts. The major peaks in the acidic fraction are a series of n-alkanes (^C 13 -C 20 ) along with minor amounts of phenols.

Since industrial effluents are routinely monitored for phenols, and

since these values reflect to some extent the efficiency of the particular control technology or clean-up method utilized, we decided to determine the concentrations of several phenols in the effluents. Two methods

were used to measure phenol and o-cresol concentrations in the BioUnit

and Plant effluents. The first method involved GC/flS SIM analysis of

the CH 2 C1 2 extract using an internal standard. The second method was the ASTM colorimetric procedure.

£-Cresol was chosen as the internal standard in the GC/MS quantitation since preliminary SIM GC/MS analysis of the BioUnit and Plant

effluent extracts showed the £-cresol to be present at a level at least

100X lower than either the phenol or o-cresol. The £-cresol was added

to aliquots of the BioUnit and Plant effluents at the 1 ppm level. The

samples were extracted and the acid fractions analayzed by GC/liS with

SIM on the 30M SP-1000 column, operated isothermally at 190°. Although

the o-cresol and phenol are not completely resolved under these conditions, the use of selected ion monitoring allows determination of each

compound free of interference from the other (see figure ^ ). Phenol and

45
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b 0 dimethylformamide

c 9 C4-pyridine

d, C3-pyridine (front)

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48
o-cresol

Figure 5. GC/MS SIM Analysis of SRC BloUnlt Effluent - Acids

49
o-cresol concentrations were determined from the respective peak areas,

the internal standard concentration, the extraction recoveries, and the

relative response factors for the phenol and o-cresol relative to j)-cresol

which were determined independently. The results of these determinations

are summarized in Table 12.

Table 12. GC/MS analysis of aqueous effluents.

phenol (ppb)

SRC BioUnit Effluent H2 0: 38.2 ± 1.9

SRC Plant Effluent H2 0: 18.8 ± 0.6

o-cresol (ppb)

3.26 ± 0.24

2.12 ± 0.2

Total phenol concentrations in the effluents were also determined

using ASTM D procedure #1783-70. Standard aqueous phenol solutions

from 10-100 ppb were used to construct a calibration curve. The BioUnit

and Plant effluent samples were analyzed and the phenol (total) concentrations determined from the calibration curve. The results are sum- marized in Table 13.

Table 13. Colorimetric analysis of aqueous effluents ASTM D

procedure 1783-70.

Sample Phenols cone.

BioUnit effluent 125 ppb ± 20%

Plant effluent 69 ppb ± 20%

Whereas the GC/MS quantitation was specific for phenol and o-cresol, the

values obtained using the ASTM procedure represent the totaT phenols in

the samples. This may account for the discrepancy between the two sets

of values, although factors such as potential interferences in the

colorimetric assay and non-linearity of the calibration curve must also

be considered.

50
3. Application of Mul ti -Dimensional Chromatography to Trace Organic

Compound Quantitation

S. N. Chesler, F. R. Guenther

A mul ti -dimensional gas chromatographic technique has been devised

for the analysis of single compounds in complex matrices. A simple

switching device was constructed which allows the transferring of a portion of the effluent from one capillary column to another capillary

column. Under proper conditions, this transfer can be done without

the use of cryogenic trapping on the second column.

This technique was used to certify 5, 6-benzoqui noline in the Shale

Oil SRM. An aci d/base extraction scheme was used to isolate the

N-heterocyclic containing fractions. The fraction was then concentrated

under a stream of dry nitrogen to approximately 100 yL. Two yL was then

injected onto the first column, a non-pol ar SE52 capillary column, to

give a boiling point separation. Subsequently, a portion of the effluent

containing the compound of interest was transferred from the first column

to a carbowax 20M capillary column. Separation on this column is based

on polarity. The analyte was easily separated from all other compounds.

A standard addition technique was used with phenenthridine as an internal

volume corrector. This procedure was used on eight separate groups of

ampoules from the SRM lot. The final concentration was determined to be

15.1 ± 1.2 ppm (one standard deviation). This compares favorably with

the liquid chromatographic determination of 16.3 ± 1.8 ppm.

4. Combined LC/MS Technique for Direct Quantitative Analysis of

Individual Organic Compounds in Complex Mixtures

R. G. Christensen, H. S. Hertz, S. Meiselman, E. White V

An interface for a conventional liquid chromatograph and a conventional mass spectrometer has been constructed which operates on the principle of pre-concentrating a liquid stream and then admitting

part of it to the ionization region of the mass spectrometer. The

selectivity of the mass spectrometer and the reproducible behavior of

the entire system allow the direct quantitation of substances in complex

mixtures.

The pre-concentration is accomplished by allowing the effluent from

the liquid chromatograph to flow down a heater wire. The evaporation

of solvent has yielded up to a 20-fold enrichment of analyte, and it is

believed that 100-fold enrichment is feasible.

The flow into the mass spectrometer is controlled by a small

needle valve built into the tip of the inlet tube. The valve is formed

by a 0.05 mm teflon film at the tip of the tube pierced by a pointed 0.1 mm wire which passes throught the bore of the tube. Flow rate into the mass spectrometer can be controlled in the range of 0-20 yL/minute.

Since all of the pressure drop occurs at the high vacuum end of the

tube, boiling within the tube with consequent unstable flow is avoided.

51
The stability of the system is such that quantitation can be done

with external as well as internal standards. Figure 6 shows typical

chromatograms from the determination of phenol in a shale oil matrix

using external standards. The level found was 400 ± 40 ppm, a value in

good agreement with, and with precision comparable to, two other methods

requiring lengthy sample pretreatment. The direct shale oil determination by LC/MS required about 15 minutes per run.

5. Work Plan and Evaluation/Feasibility Study of Drilling Fluid

Reference Standards for Chemical Analysis

J. R. Moody

Background

Man's activities in off-shore drilling (as well as on-shore drilling)

must proceed in order to locate new sources of oil and gas to satisfy

the increasing demands for energy resources. If we are to preserve our

renewable resources as we extract oil and gas from the continental

shelf, research, development, and monitoring are needed to provide a better foundation for rational decisions on minimizing risks and protecting other resources.

Drilling fluids are now recognized as one of the major factors

involved in the success or failure of drilling operations. The com- position of a drilling fluid depends upon the formation to be drilled.

Drilling fluids normally consist of colloidal suspensions of clay and

minerals in water with chemical additives, and are used in production

operations to support the borehole, to remove cuttings, and to cool the

drill bits. In order to control the physical and chemical properties of

drilling fluids, several types of inorganic and organic chemicals are used in conjunction with the clays, minerals, thinning and dispersing

agents, etc. Since disposal of the drilling fluids is into water or onto adjacent land, it is essential to characterize these fluids for

their chemical constituents in order to evaluate and assess the fate of

the chemical constituents (many of them toxic) on the aquatic and

terrestrial environment.

Scope

NBS will develop and provide EPA/Gulf Breeze with drilling fluid

reference standards for use in characterization efforts and in a quality

assurance program to improve and maintain reliability of measurements

made on discharges from drilling and production operations.

Milestones :

(1) Obtain candidate reference material (s) from EPA/Gulf Breeze

and assess the feasibility for preparing a dry mixture of

four major drilling fluid components

(2) If milestone (1) proves feasible, prepare a batch (i.e.,

grind, blend, sieve) of material and establish homogeneity

52
Figure 6. Chromatogram of shale oil obtained during phenol quantitation.

Upper trace: ultraviolet detector recording at 254 nm. Lower

trace: single ion record at m/z 94.

53
(3) Characterize the drilling fluid mixture for several trace

elements to be determined by NBS and EPA/Gulf Breeze

(4) Package, label, and provide EPA/Gulf Breeze with drilling

fluid reference standard for specified trace elements

(5) Initiate studies on a drilling fluid material chosen in

concert with EPA/Gulf Breeze for future (FY81) issuance as

a more complex or more characterized standard

Progress

EPA/Gulf Breeze provided NBS with three test "fluids" for feasibility and assessment studies. As a result of these studies, EPA/Gulf

Breeze and NBS have agreed that the reference drilling fluid sample

should consist of a dry mix of the components found in drilling mud.

NBS has ordered and received the five major components of drilling mud - barite, bentonite, chrome lignosulfonate, lignin, and caustic soda.

The first three components have been blended in a dual V blender.

Samples of this blend will be analysed to confirm or deny the apparent

homogeneity of the sample. Conceivably, some re-segregation of the

sample may occur on storage due to the large difference in component

densities. Therefore, some effort will be made to determine the degree

to which this may happen. Packaging in small units and requiring use of

the entire sample in an experiment would be another way around this

problem.

If lignin is added in the solid state with caustic soda, two problems

arise. First, the oil companies believe that the total mixture of dry

components will not mix with water to yield the normal mud. Secondly,

caustic soda is hygroscopic and in a flake form (all other components

are powders, 200-400 mash). It would have to be ground (difficult to

do) in order to blend well with the other components. At this point, it

would be appropriate to solicit reaction to a three component dry mix

because of the problems associated with a 5 component mix.

6. Atomic Absorption and Flame Emission Spectrometry

J.D. Messman, T.C. Rains, M.S. Epstein

The major effort in atomic absorption (AAS) and flame emission

(FES) spectrometry has been directed toward the characterization of

Standard Reference Materials and the development of reference methods.

Research activities have been in the development of continuum source AAS

and metal speciation using high performance liquid chromatography- AAS.

As part of the continuing effort to improve NBS analytical ex- pertise in atomic absorption spectrometry, a practical atomic absorption

spectrometric system has bden developed which utilizes a single con- tinuum source in conjunction with a high resolution, wavelength-modulated

echelle spectrometer. This technique can be described as ContinuumSource Echelle Wavelength Modulation-Atomic Absorption Spectrometry

(CEWM-AAS). It has been successfully applied to the analysis of NBS

Standard Reference Materials as well as other diverse complex samples.

54
There are numerous advantages of CEWM-AAS over existing state-ofthe-art commercial atomic absorption instrumentation. Wavelength

modulation provides true double beam operation using a simple single

beam optical arrangement. Electronic ratioing of the AC component

(propotional to I Q - 1 ) of the photosignal to the DC component (proportional to I 0 ) of the photosignal results in an AA instrument which gives

a real time absorbance readout, continuously corrected for source

attenuation resulting from background absorption. Systematic error in

CEWM-AAS is minimized because of accurate compensation for al

1

known

major types of spectral interferences encountered in atomic absorption

analyses. Moreover, high levels of nonspecific background interference

can be corrected for in CEWM-AAS. This advantage makes direct analyses

of low levels of trace metals in complex matrices such as biological

fluids and lubricating oils feasible.

The CEWM-AAS allows the utilization of either flame or electrothermal atomization reservoirs while the use of a single continuum

source as the external primary source of radiation obviates the ex- pensive library of hollow cathode lamps and electrodeless discharge

lamps required of all commercial atomic absorption instrumentation.

Once CEWM-AAS has been critically evaluated in the single element

mode, the potential of the CEWM-AAS system for multielement analyses

will be thoroughly investigated. Instrumental change from the singleelement mode to the multielement mode of operation is simple and con- venient since the echelle spectrometer is easily converted into a 20

channel, direct reading polychromator by merely replacing the single

exit slit cassette with a multichannel exit slit cassette. Each of the

20 photomultiplier tubes will be individually interfaced, via analog-todigital converters (ADC's), to a PDP 11/34 minicomputer for data acquisition, storage, and reduction.

One obvious benefit of simultaneous multielement AAS is a much

greater throughput of routine samples. This allows the analyst to

devote more time to improving accuracy and precision of AAS through

methods development and studies aimed towards the elimination of potential interferences. Moreover, simultaneous multielement AAS is quite

amenable to those applications where several trace metals need to be

determined in a limited sample volume such as blood serum from a pediatric patient.

During the past year, CEWM-AAS (operated in the single element

mode) has been used to analyze a wide variety of Standard Reference

Materials including coal, coal fly ash, estuarine sediments, unalloyed

copper, and a synthetic natural water matrix for a number of trace

metals. In Table 14, the results from four trace metals (Ag, Cr, Cu, and

Ni) in a synthetic natural water matrix (SRM 1643a) obtained by CEWMAAS are compared to those values obtained with a commercial line-source

AA instrument (Perkin-Elmer Model 603) using electrothermal atomization.

When operated in the single element mode, analytical performance of

CEWMAAS is shown to be as good as, or better than, that using a com- mercial single element, line-source atomic absorption instrument.

55
Table 14. Trace Elements in Water by Atomic Absorption Spectrometry

NBS-SRM 1643a

Element

Concentration

ng/mL Standard Deviation

Ag 2.54

b

0.13

2.93c 0.19

Cr 18.

5

b

1.1

17.

6

C

0.7

Cu 18.

l

b

1.2

17.

8

C

0.7

Ni 55.

9

b

4.9

56.

5

C

3.5

a 0ne standard deviation of six replicate samples

b

PE 603/HGA-2200/D

2

C CEWM/HGA-2100

Activities are underway to develop analytical procedures for the

determination of seven trace metals (Cd, Cr, Cu, Mn, Pb, Ni , and Zn) in

a coal matrix by CEWM-AAS. A subbi tuminous coal (SRM 1635) typical of

the coal matrix found in the western region of the United States, is

being used as the control material. Analytical conditions for each

metal are being optimized for determination by the CEWM-AAS system

operated in the single-element mode using electrothermal atomization.

Upon completion of this preliminary study, efforts will focus on the

assessment of the accuracy, precision, and linear dynamic range for each

metal in SRM 1635 as well as any compromises in the analytical con- ditions which may be necessary when these seven elements are measured

simultaneously by CEWM-AAS.

a. Metal Speciation Using High Performance Liquid Chromatography/Atomic

Absorption Spectrometry

J. D. Messman, T. C. Rains

During recent years it has become increasingly apparent that total

metal data alone may not provide complete and accurate descriptions of

the complicated roles which many metals play in our ecosystem. It is

generally believed that alkylated forms of certain metals (e.g., Hg, Pb,

and Se) are much more toxic than the inorganic salts of the metals or even the metals themselves. Some microorganisms are capable of chemically

56
and biochemically transforming certain toxic elements into more toxic

organometallic compounds which may then be released into the environment.

Additionally, chemical speciation of trace metals can be a real problem

in defining nutrient composition of foods because the biological activity

of a metal such as chromium or iron depends on the chemical species to

which the metal is bound.

The rapidly increasing interest in metal speciation in diverse

scientific disciplines has prompted the immediate need for development

of analytical instrumentation which allows the determination of not only

the total metal content but also the different chemical forms in which

the metal may be distributed. Atomic spectrometric techniques (absorption, emission, and fluorescence) have long been regarded as being

sensitive and metal -specific spectrochemical technqiues for total metal

analyses are limited in their ability to differentiate between various

chemical forms of the metal within the sample. Chromatographic techniques can be successfully employed to separate various chemical forms

of the analyte, but poor detector specificity frequently limits their

analytical utility when highly complex mixtures are encountered. However,

interfacing chromatographic and atomic spectroscopic instrumentation

into a single analytical hybrid system which has the combined advantages

of both techniques presents a viable means of potentially solving

analytical problems which otherwise would not be possible by either

individual technique.

in an effort to gain more knowledge about the metal distribution in

complex matrices, an investigation has been undertaken using the com- bined instrumentation of a flame atomic absorption spectrometer interfaced to sample the mobile phase exiting at the outlet of the analytical

column of a high performance liquid chromatograph (HPLC). To demonstrate

the analytical feasibility of HPLC/AAS for molecular characterization of

metals in complex matrices, tetraalkyl lead (TAL) compounds were determined directly in gasoline. Baseline resolution of the TAL mixture con- sisting of tetramethyl lead (TML), trimethyl ethyl lead (TMEL), dimethyl

diethyl lead (DMDEL), methyl triethyl lead (MTEL), and tetraethyl lead

(TEL) was effected by reverse-phase HPLC using a 70 percent acetonitrile

(CH 3 CN)/30 percent H 2 0 mobile phase. The eluted tetraalkyl lead species

were then sequentially atomized in an air/ acetylene flame. The lead

absorbance for each TAL compound was measured by atomic absorption

spectrometry using the 283.3. nm lead resonance line. Analyses were

conducted free of spectral interferences. Detection limits for lead by

this hybrid technique were about 10 ng for each TAL compound. Using our

instrumental configuration and analytical conditions, the 5 tetraalkyl

lead compounds were separated and detected in less than 10 minutes. A

number of different commercial gasolines were analyzed for their tetraalkyl lead content. The TAL distribution was found to vary widely among

manufacturers

.

Atomic absorption spectrometry has been compared in terms of

analytical performance to UV absorbance spectrophotometry as a detector

for HPLC for the determination of tetraalkyl lead compounds in petroleum

refinery products. Preliminary data indicate that for certain applications the metal-specific AA detector is more analytically useful as an

57
HPLC detector than UV absorbance spectrophotometry for the study of

different metal species in complex matrices. In some cases, the UV

absorbance detector is severly plagued by spectral interference at 254 nm

due to coeluting aliphatic, olefinic, and aromatic hydrocarbons of the

gasoline matrix which absorb at this wavelength. As shown in figure 7,

a clean chromatograph of tetraalkyl lead compounds in gasoline is obtained

with the AA detector because it responds to only lead-containing compounds

at 283.3 nm line.

In order to improve the analytical performance of the HPLC/AAS

system described in this preliminary report, it is necessary to optimize

the chromatographic conditions and to decrease the dead volume present

between the column and the detection system. In addition, the detection

limits can be significantly lowered by using a flameless atomic

reservoi r.

The HPLC/AAS technique can be easily extended to the determination

of different organometallic compounds in diverse matrices by simply

tuning the monochromator to the analytical line of the metal of interest.

This inherent specificity of AAS cannot be realized by existing commercial

HPLC spectroscopic detectors. Moreover, the specificity of AAS considerably

relaxes the constraints of the analytical conditions required for the

separation. With AAS, only the compounds containing the metal of

interest need to be separated from one another; the metal-containing

compounds need not necessarily be separated from the sample matrix.

58
UV Absorbance Detector

(254 nm)

Flame AA Detector

(283.3 nm)

DMDEl

&

G

Figure 7. Director Determination of Tetraalkyl Lead

Compounds in Gasoline by Reverse-Phase HPLC
7. Interferences in the Inductively Coupled Plasma (ICP) Technique

R. L. Watters, Jr.

In the application of the ICP technique to high-accuracy analysis of

Standard Reference Materials (SRM's), interferences have been found which

can degrade the quality of analytical results. These interferences can

be traced to spectral and matrix-related interactions which must be

characterized and corrected for in order to minimize their effect. The

problem of spectral interference in the ICP technique is well known.

Procedures for background and spectral overlap corrections have been

established and are presently being employed in this laboratory. The

first step is to expose a photographic plate with spectra of the sample

and pure-element standards. Spectral lines are then chosen from con- siderations of sensitivity and absence of spectral overlap. The exitslit carriage is mounted on the microdensitometer with the reference

photographic plate, and slits are positioned in alignment with the chosen

lines on the plate. Final alignment is accomplished by adjustment of

a refractor plate in front of each slit.

A wavelength scan of each element is stored in the computer for

output on the terminal. From plots of intensi ty-versus-wavelength for

each element, the spectral peak position is checked and background correction points on either side of the peak are chosen. Spectral scanning and

background sampling are accomplished by computer-controlled rotation of a refractor plate positioned behind the spectrometer entrance slit. In this

manner, true net intensities for the spectral lines are calculated and

either stored in the computer for calibration or displayed on the terminal.

Evidence has been found indicating differences in analytical response

between pure-element standards and samples of complex matrices which are not due to spectral interference. These effects become significant when

applying the ICP technique to high-accuracy analysis of SRM's. Chemical

matrix effects in the plasma itself can cause up to fifteen percent relative enhancement or depression of the analyte element intensity depending

on the spectral line and plasma operating conditions. Complete definition

of the problem has involved examination of compromise conditions for

simultaneous multielement analysis both from the point of view of sensitivity as well as matrix effect suppression.

One way to estimate a suspected matrix effect is to record net

intensities for various elements at constant concentrations, with and

without an excess (3000 yg/mL) of potassium present. The ratio of

intensity with potassium to intensity without potassium can be plotted

with respect to an instrument variable such as power, or observation

height. The objective is to find operating conditions which result in

a ratio close to 1.00 without significantly affecting the signal-tobackground ratio. At present, no serious degradation in signal-tobackground ratio has been caused by tuning the ICP for minimum matrix

effect. However, the data include only five elements thus far, therefore

the results must be considered to be preliminary. This data, as well as its extension to additional elements and matrices, will provide the information necessary to minimize analytical bias in simultaneous multielement analysis using the ICP technique.
(5) Radiological Pollutant Quality Assurance

Participating Staff: Center for Radiation Research - J.M. R. Hutchinson

,

J.R. Noyce

Background/Objecti ve The assessment of regional and national effects of radionuclides

depends on the comparability of empirical data generated throughout

the new energy developing industries as well as the existing nuclear

power industry. The need for a program to provide scientifically

valid reference points from which future radiological environmental

degradation can be measured and upon which rational policy decisions

may be made has been recognized.

The primary objective of this project is to aid in the development

of optimum radiological monitoring program to provide radiological

pollutant quality assurance. Studies at NBS leading to the attainment

of this objective include: (1) the improvement of radiological

monitoring techniques; (2) the evaluation of presently used

environmental radiological surveillance programs; (3) the provision

of standards for measurement of radionuclides.

FY-1980 Milestones

° Prepare and deliver SRM for thorium-232 - a naturally occuring

radionuclide found in coal and likely to be present in coal

plant effluents.

° Prepare and deliver a mixed solution SRM (i.e. 3H, 90 Sr, 134 Cs,

226 ' 228 Ra) needed to support measurements required by the Interim

Drinking Water Regulations.

FY-1980 Accomplishments

1 . 232 Th Solution

Thorium-232 is a radionuclide whose presence is of concern when in

effluent and run-off waters from some types of mines, ore mills, and tailing

piles, and in certain drinking water supplies. This calibrated solution

of 232 Th is for laboratories that assay these waters. The starting material was all thorium nitrate, chosen so that the 232 Th progeny would be in

radioactive equilibrium. The 232 Th content was assayed by isotopedilution mass spectrometry and confirmed by y-ray counting. Two impurities were observed and measured: 230 Th by means of a-particle spectrometry with a silicon surface-barrier detector, and 226

Ra by means of

Ge(Li) detector spectrometry. The a-particle spectrum is shown in

Figure 8, and the Report of Calibration is given at the end of this section.

Two hundred ampoules of this solution were provided to EPA-LV.

2. Mixed Radionuclide Solutions

Two mixed radionuclide solutions were needed by EPA to distribute

to laboratories that assay for radionuclides in drinking water. One

solution mixture is a ten-fold dilution of the other. Each mixture

contains 3 H, 90 Sr- 90 Y,

134 Cs, 226

Ra and its progeny, and natural uranium

and its progeny. The 228

Ra and natural uranium components were developed

61
earlier in this multi-year program; the 134 Cs solution was calibrated

specifically for these mixtures. A Report of Calibration for one of the

mixtures is given at the end of this section.

62
CHANNEL NUMBER

Figure 8. ALPHA PARTICLE ENERGY, MeV

63
(REV. U-CS)

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

WASHINGTON, D.C. 20234

REPORT OF CALIBRATION

THORIUM-232 SOLUTION

prepared for the

Quality Assurance Division

Environmental Monitoring and Support Laboratory

U.S. Environmental Protection Agency

Las Vegas, Nevada

This solution consists of thorium-232 and progeny in equilibrium in approximately

4.0 grams of one-molar nitric acid in a flame-sealed borosilicate-glass ampoule.

The solution was prepared by dissolving old thorium nitrate in dilute nitric acid

and filtering the solution through a membrane-type filter having 0.3-micrometer

openings. Information from the supplier about the thorium nitrate is given in the

appendix to this Report.

Two hundred and twenty ampoules containing approximately equal portions of this

solution were prepared. Six of these ampoules were assayed for thorium concentration by isotope-dilution mass spectrometry in May 1979. These assays by the

Inorganic Analytical Research Division, National Bureau of Standards, are described

in the attached memorandum. The mean value from the assays is 0.04738 gram of

total thorium per gram of solution. The total uncertainty in this value is 0.5

percent.

The radioactivity concentration of thorium-232 in the solution, which was calculated

from the mass-spectrometric value and the conversion factors and constants in Table

1 , is

*1.92 x 102 s'V1 ± 1.8%*.

In making this conversion, all of the thorium was assumed to be thorium-232, on a mass basis.

The uncertainty in the radioactivity concentration, 1.9 percent, is the linear sum of the total uncertainty in the mass-spectrometric value and three times the un- certainty in the thorium-232 half life.

The thorium nitrate from which this solution was prepared contains radium-226 and

thorium-230 impurities. An ampoule of the solution was assayed for thorium-232

and radium-226 by measuring the emission rates of gamma rays from the decay of their

respective progeny with a Ge (Li )-detector spectrometer. The radioactivity concentraof thorium-232 obtained from this assay agreed, to within four percent, with the

value derived from the mass-spectrometric assays. The ratio of the radioactivity

concentration of radium-226 to that of thorium-232 was 0.010 ± 0.003 in July 1979.

64
- 2 -

The thorium-230 to thorium-232 activity ratio of a dried deposit of this solution

was calculated from the results of silicon surface-barrier-spectrometer measurements to be 0.15 ± 0.01. The radioactivity concentration of uranium-238 was estimated from the alpha-particle spectra to be less than 0.5 percent of that of

thorium-232, and likewise for uranium-234.

1) M. R. Schmorak, "Nuclear Data Sheets for A=232, 236, 240", Nucl . Data Sheets,

20, 165 (1977).

2) A. H. Wapstra and K. Bos, "The 1977 Atomic Mass Evaluation, Part I. Atomic

Mass Table", Atomic and Nucl. Data Tables , 19 , 177 (1977).

3) Recent, unpublished value, National Bureau of Standards.

TABLE 1. RELEVANT CONVERSION FACTORS AND CONSTANTS

Half life of 232 Th = (1.405 ± 0.006) x 10 10

y (D

Atomic mass of 232Th = (232.038053805 ± 0.000002515) amu ( 2 ) Avogadro constant = (6.0220978 ± 0.0000010) x 1023 (3)

Length of tropical year = 3.155693 x 107 s ^

^Based on the ephemeris second.

REFERENCES

For the Director,

W. B. Mann, Principal Scientist

Radioactivity Group

Center for Radiation Research

March 12, 1980

65
APPENDIX TO REPORT OF CALIBRATION

THORIUM-232 SOLUTION

The following set of data about the thorium nitrate used for this

provided by the supplier, and is given here for information only.

The thorium in the compound, Th(N03 )4*6H2 0, was purified in 1906.

metric assays of the compound in 1954 gave these results for some

ement Content, ppm

Li < 5

Na < 25

K < 5

Ca 3

Rb < 5

Sr < 3

Cs < 25

Ba 3

solution was

Spectrophotoimpurity metals.

65a
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington. D.C. 20234

June 11, 1979

MEMORANDUM FOR Jim Noyce

Through:

From: J.

Subj ect

:

E. L. Garner

W. Gramlich and L. A. Machlan V|u>g

Mass Spectrometric Analysis of Thorium Samples

Submitted by Jim Noyce

The concentration of thorium has been determined in six

ampoules of thorium nitrate solution by isotope dilution

mass spectrometry. Approximately 1 g of solution was

withdrawn from each of the six ampoules and transferred by

weight to 200 mL flasks. These solutions were diluted by

weight to approximately 180 g with 0.5N HNO 3 . After thoroughly

mixing, approximately 1 g of aliquotes were withdrawn and

transferred by weight to Teflon beakers. A second aliquot

was withdrawn from two of the flasks for duplicate assay and

a second aliquot was withdrawn from two other flasks for

determination of the isotopic composition. A weighed

aliquote of a

230 Th solution of known concentration was

added to each of the eight samples for isotope dilution

analysis, and after mixing the solutions were evaporated to

dryness

.

The samples were analyzed by thermal ionization mass spectrometry

using a triple filament rhenium source with a zone refined

rhenium ionizing filament. Three blanks processed with the

samples averaged less than 0.2 ng of thorium. The two

isotopic composition samples yielded a 232 Th/ 230 Th ratio of

greater than 1 x 10 5

. The results of the isotope dilution

analysis is reported in the accompanying table.

66

(OVER)

Concentration of Thorium in Thorium Nitrate Solutions

Sample No. Aliquot Percent Th

A- 1 (#2) 1 4.738

2 4.745

A-2 (#110) 1 4.730

A- 3 (#57) 1 4.746

A4

(#166) 1 4.736

A5

(111) 1 4.742

2 4.740

A-6 (#217) 1 4.728

Average = 4.738

s = 0.0066

The total uncertainty in the average percent thorium by weight, 0.5

percent, is the linear sum of 0.2 5 percent, which is the uncertainty

(at the 95-percent confidence limits) in the concentration of the

thorium-230 spike, and 0.2 5 percent, which is the uncertainty (at

the 95-percent confidence limits) in the mass-spectrometric measurements for thorium-232.

67
form NBS-44S

(REV. Il~*3)

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

WASHINGTON, D.C. 20234

REPORT OF CALIBRATION

MIXED RADIONUCLIDE CALIBRATED SOLUTION M2

prepared for the

QUALITY ASSURANCE DIVISION

U.S. ENVIRONMENTAL PROTECTION AGENCY

LAS VEGAS, NEVADA

This calibrated solution consists of hydrogen-3, stronti um-90-yttri um-90 , cesium134, radium-226 and its progeny, radium-228 and its progeny, and uranium of

natural isotopic composition and its progenies in approximately 4.2 g of carrier

solution in a flame-sealed, borosi 1 i cate-glass ampoule. The carrier solution is

1 M HNO

3 containing approximately 10 ug each of stable strontium, yttrium, cesium,

and barium per gram of solution, and is approximately 0.1 M in HC 1 . The ampoule

contains part of a master solution which was prepared by the gravimetric addition

of a quantitative mixture of individually calibrated solutions of the radionuclides

to a known mass of the carrier solution.

The radioactivity concentrations on January 1, 1980, the total uranium concentration

by mass, their uncertainties, and the half lives used in the decay calculations are given in the attached table.

The hydrogen-3 used in the preparation of this mixture was Standard Reference

Material (SRM) 4927-B. The stronti um-90-yttri um-90 was a portion of the solution

from which SRM 4919-0 was quantitatively prepared. The activity of the cesium-134

solution was measured using the National Bureau of Standards (NBS) pressurized "4tt"y

ionization chamber that had previously been calibrated with a cesium-134 standard

in terms of a radium-226 reference source. The radium-226 used in the preparation

of this mixture was a portion of the solution from which SRM 4953-B was quantitatively prepared. The radium-228 was the NBS calibrated solution of July 1977. The

uranium in the mixture came from the NBS calibrated solution of natural uranium of

November 1978, plus part of the more concentrated solution from which the 1978

uranium solution was quantitatively prepared.

The total uncertainty in the radioactivity concentration of each radionuclide and

in the total uranium concentration by mass is the linear sum of the 99-percent

confidence limits for the mean and the estimated upper limits of conceivable systematic errors in the calibration, the decay calculation (where applicable), and

the preparation of this solution.

68
- 2 -

Each radioactive component of the mixture was examined for gamma-ray-emitting

impurities using germanium-spectrometer systems that covered the energy region from

90 to 1900 keV. Radium-226 and its progeny were observed in the radium-228 and

uranium solutions. Radium-228 and its progeny were observed in the uranium solution.

The radium-226 and radium-228 impurities are included in the total radioactivity

concentrations reported for these nuclides. No other gamma-ray-emitting impurities

were identified.

For the Director

Attachment

March 1980

W. B.

Radioactivity Group

Center for Radiation Research

69
MIXED RADIONUCLIDE CALIBRATED SOLUTION M2

PARENT s^g"1 ON UNCERTAINTY, %

RADIONUCLIDE

JAN. 1, 1980

(99% C.L.

)

SYSTEM- 1 ATIC

TOTAL HALF LIFE,

YEARS

3

H 236.1 0.2 0.6 0.8 12.35 ± 0.0l( b )

9Q$ r 1.45 1.3 0.9 2.2 29.12 ± 0.24(b)

13-» Cs 10.47 0.4 1.3 1.7 2.062 ± 0.005(b)

226 Ra 0.891 0.1 1.7 1.8 1600 ± 7(b)

2?8Ra 0.731 1.4 2.0 3.4 5.75 ± 0.03(c)

234y 1.22 3.9 1.4 5.3 (2.445 ± 0.010)

X 105(c)

235y 0.05872 0.1 0.4 0.5 (7.038 ± 0.005)

x 108 ( d )

238u 1.272 0.1 0.4 0.5 (4.468 ± 0.003)

X 109(C)

TOTAL U

i

0.1031(a) 0.1 0.2 0.3

( ^Milligrams of U per gram of solution, by isotope-dilution mass spectrometry.

The radioactivity concentrations of the uranium isotopes were determined

from this concentration, the isotopic abundances measured by mass spectrometry,

and the respective uranium half lives.

(b)NCRP Report No. 58, App. A, National Council on Radiation Protection and

Measurements, Washington (1978).

^ c )D.C. Kocher, 0RNL/NUREG/TM-102, Oak Ridge National Laboratory, Oak Ridge,

TN (1977).

< d )M.R. Schmorak, Nucl . Data Sheets, 21, 91 (1977).

69a
WATER MEASUREMENTS - METHODS DEVELOPMENT

a. Overview

A major emphasis in the recent water pollution legislation is

upon protecting human health and natural resources ^. c°ntrol ^/ g

;4 ^

x and hazardous substances. With our advancing industrial econoniy an the emerging of new technologies, thousands of substances are being

used which did not exist until the last few decades. As

.u^to^redi ct

to control pollutants in our Nation's waters we must be able to predict

their behavior and effects in such an environment. The development of

testing procedures is necessary to provide this predictive capability.

The activities in this task involve the development of new and improved

methodologies anS instrumentation needed to identify, characterize, and

quantify constituents in aqueous effluents.

Objective

Develop new and improved measurement methods and associated instrumentation for the measurement of water pollutants and to assess

the Derformance of special field studies and analyses related to char

acte

P

rtzing the levels of water pollutants injected into the environment

by new technologies and energy developments; and provide verified a

on the chemical and physical properties of/^Vnf1 Militants in ' relationship of these properties to concentration of po^utants in

effluents with concentrations of pollutants in natural bodies o water.

Interaction

Strong interactions are maintained with other units of the NBS

community - Center for Analytical Chemistry, S

£|nte?Vor

Reference Materials, Office of Standard Reference Data, Center for

Radiation Research, Center for Thermodynamics and Molecular science,

Certfr for Materials Science, Center for Mechanical Engineering and

Process Technology, Center for Applied Mathematics and w^h °ther

Federal agencies - (EPA, DoE, NOAA, Dol). The activities in this task

also involve interactions with industry, state and Toca

e?°o%ani Nations

research laboratories, universities, as well as related

*

(e.g.. Council on Environmental Quality, ASTM) engaged 1n [e*atea

activities which impact the development of standards for P measurements

.

Task Justification

The national effort in water pollution abatement involve muni cip

and state government agencies, industries,

"o "ater

every department of the Federal government In

j

r®s P on!^°

6wa ^c. )

,

ears

70

are being issued by the Environmental Protection Agency. Measurement

techniques are either inadequate or do not exist to characterize and/ or determine the low concentration levels of pollutants in effluents.

b. List of Projects

Project Title

Source of

Funding

(1) Methods Development for

Organic Analysis

E/E-EPA

(2) Methods Development for E/E-EPA

Inorganic Analysis and

EPA Chesapeake Bay

71
(1) Methods Development for Organic Analysis

Participating Staff: Center for Analytical Chemistry and Center

for Thermodynamics and Molecular Science

Background/Objecti ves

In order to evaluate the environmental impact of expanded or new technologies, measurement techniques and monitoring systems are required in the development of a compatible data base to evaluate

the total effects of energy development upon our environment and to

make rational policy decisions. Measurement techniques are either

inadequate or do not exist to characterize and/or determine the low

concentration levels of organic pollutants. Advanced measurement

methods and instrumentation need to be developed to enable accurate

measurement of energy related organic pollutants, as well as, data

quality assurance of special field studies and analyses related to

levels of pollutants injected into the environment.

The activities in this project focus on the development of mea- surement methods and instrumentation to enable the analysis of

trace organic pollutants. Research efforts also focus on developing and applying Liquid Chromatography - Electrochemical

Detection (LC-EC) to the characterization of effluents for trace

organometals. Research efforts in this project compliment research

at EPA to achieve a means of sampling and analyzing pollutants in

water from energy related technologies.

FY-1980 Milestones

° Support the ERL/ Athens laboratory in its major project-development

of a master analytical scheme for the analysis of all gas chroma tographi call e organic compounds in waters associated with effluents

from energy- related industries.

° Continue method development/ refinement using LC-MS and GC-MS

technology to enable analysis of trace volatile and non-volatile

organic pollutants in water.

° Development of advanced measurement and/or field monitoring techniques

for non-volatile organic pollutants in effluents.

Selected Technical Highlights

1 . Synthesis, Isotopic and Purity Analyses, and Preparation of

Solutions of Stable Isotope Labeled Marker Compounds for

Priority Pollutant Analysis

S.N. Chesler, B. Coxon, P. Konash, W. E. May, R. M. Parris,

L. T. Sniegoski, M. J. Welch, E. White V

A "Master Analytical Scheme" being developed for the Environmental

Protection Agency by the Research Triangle Institute and Gulf South

Research Institute is intended to allow qualitative and quantitative

analysis of organic chemicals in water by gas chromatography/mass

spectrometry. The "Master Analytical Scheme" requires the use of

72
internal standards to be developed by NBS. The standards each consist

of seven to eleven deuterated compounds in a solvent. Three different

mixtures for "purgeable," extractable," and "intractable" organic

compounds, each at two concentration levels (ranging from 0.25 yg/L

to 2500 yg/L per component), are needed.

Of the 25 deuterated compounds required, two 2- aphthalenesulfonic

acid-d7 and dodecylphosphate-d25 » were synthesized at NBS because they

were not commercially available. The reaction sequences used are as follows

:

2-Naphthalenesulfonic Acid-d 7

(C

fi H r 0) ? P0Cl

CD-, (CD o ),-,0D -—---7“

2 Ml pyridine

0 co

3

(cd

2

) 11 op(oc

6

h

5

) 2

H

2

/Pt

HOAc''

cd

3

(cd

2

) 11 op(oh).

All dehydrated compounds were checked for chemical purity by mass spectrometry and either gas or liquid chromatography, and for isotopic

purity by mass spectrometry.

Since some of the compounds were potentially unstable when stored

in mixtures, several test mixtures similar to the internal standards,

but of undeuterated compounds in deuterated solvents, were prepared.

These were subjected to conditions to accelerate aging, and examined by

nuclear magnetic resonance spectrometry. Although some decomposition

was observed, the rates were such that properly stored mixtures are expected to be usable for the required several months of evaluation of

the "Master Analytical Scheme."

Approximately 600 individual sealed vials of the various internal

standard mixtures were prepared, and the 400 required for initial tests

of the "Master Analytical Scheme" have been delivered. The remaining

vials have been retained at NBS for stability tests, which are in

progress

.

73
2. FI uoroimmunoassay Procedure Developed for Dini trophenols in Water

P. Cooper, D. J. Reeder, R. Schaffer

Detection of trace amounts of the toxic pollutant 2,4-dini trophenol

in water is an analytical problem that presents many challenges to the

analytical chemist. Laboratory investigations have shown that gas

chromatography and high-performance liquid chromatography, while suited

for analytical determinations of most of the toxic pollutants, are not

as efficient in the separation and identification of the ni trophenols.

The development of an immunochemical procedure for detection and quantitation of dini trophenols in water has been the focus of efforts during

1980.

Development of suitable reagents for the assay entailed the preparation of a suitable material (immunogen) to be injected into rabbits

for production of antibodies. Highly purified bovine albumin was combined

with dini trophenol and characterized. The immunogen most successful in

eliciting antibodies had 23 dini trophenyl groups per mole of albumin.

The antiserum was produced under contract by a commercial supplier who

injected rabbits with the prepared immunogen and bled them periodically

for determining antibody development. A procedure that used double

diffusion of antiserum versus the immunogen in a gel matrix was the

preferred method for following antibody development.

Specific immunoglobulins (IgG) were separated from serum by use of

an ion-exchange gel preparation. Purity of the IgG was ascertained by use of cellulose acetate strip electrophoresis. The IgG was then

covalently bound to solid-phase polymeric beads by coupling with a carbondiimide reagent.

The antibody, thus attached to the beads, was able to bind 2,4-

dini trophenol . However, in order to use this capability in a quantitative

assay, a compound that could act as a tracer needed to be synthesized.

In order to be suitable, the tracer requires dual functionality, i.e.,

dini trophenol reactivity as well as physical properties that can be

measured, such as radioactivity or fluorescence. A dini trophenol ated

fluorescent tracer with dichlorotriazinylaminofluorescein as the fluorescent moiety is currently being synthesized. Alternatively, the use of

other fluorescein derivatives, such as fluorescein isothiocyanate, are being considered as substrates for dini trophenyl ation.
The first tracer that we have had success in using in a quantitative competitive assay is a double-labeled rabbit albumin molecule to

which both dini trophenol groups and fluorescein isothiocyanate chromophores

are covalently bound. In the competitive assay, the tracer and free

dini trophenol compete for antibody sites on the specific antibody solidphase beads. Maximum sensitivity of the assay is determined by the

amount of antibody-bound beads added, the quantity of the competing

tracer in the mixture, and the time and temperature of assay incubation.

The solid-phase beads are separated by centrifugation, washed, and

then counted in an instrument designed for photon counting of fluores- cence at 510 nm with excitation at 490 nm. Binding curves are then

generated from the resulting counts. Typical specific counts range from

30,000 to 600,000 in a two-second counting period, with background and

control counts ranging from 15,000 to 25,000. Plots of the binding

versus the amount of dini trophenol added are linear over two orders of

magnitude. Work is now focused on extending the sensitivity range of

the assay.

By combining the specificity of the assay with capabilities of

concentrating dini trophenol s with an affinity "accumulator" column,

detection of ultra-trace amounts of dini trophenol pollutants in water

should be achieved. This will be of importance in the monitoring of

industrial effluents.

3. Correlation of Liquid Chromatographic Retention Data with

Molecular Shapes for Polycyclic Aromatic Hydrocarbons

W. J. Bonnett, F. R. Guenther, W. E. May, S. A. Wise

Reverse-phase liquid chromatography (LC) on chemically-bonded C-,g

stationary phases is presently the most popular Liquid chromatographic

separation mode. The mechanism of separation on these C-,g materials

has not been established and is a topic of much discussion and research.

75
The study of the reverse-phase retention characteristics of polycyclic

aromatic hydrocarbons (PAH's) provides valuable information because

(1) PAH's are ideal model compounds for investigating the mechanism

of retention due to their nonpolarity, and (2) the separation and

identification of PAH's are of environmental interest because of the

production of PAH's during combustion of fuel and their suspected

carcinogenic properties.

Reverse-phase LC on Ci 8 phases provides unique selectivity for the

separation of isomeric PAH's and particularly methyl -substituted PAH's.

A relationship was observed between the shape of PAH solutes, particularly the length-to-breadth ratios and the reverse-phase LC retention

on C

i

8 bonded phases. In nearly all cases, this ratio was successful

in predicting the LC elution order of isomeric PAH's for more than 40

unsubstituted and 40 methyl -substi tuted PAH's, i.e., the retention

increases with increasing length-to-breadth ratio. These ratios were found to be particularly useful in predicting the selectivity of

reverse-phase LC for methyl -substi tuted PAH's. The linear correlation

for the LC retention vs the length-to-breadth ratio for 23 methyl - substituted isomeric benzo[cJphenanthrenes , benz[a]anthracenes , and

chrysenes is illustrated in figure 9 (correlation coefficient = 0.936).

This relationship suggests the importance of solute shape in the

LC mechanism. In GC, a similar relationship exists between shape and

retention on liquid crystal phases, suggesting the possibility of a liquid crystal effect or "ordering" of the Ci 8 phase in LC. The

retention characteristics on polymeric Ci 8 phases exhibit greater

selectivity and a greater correlation with the shape data than on the monomeric phases. This observation indicates that polymeric phases

may be more "ordered" than the monomeric phases.

4. Liquid Chromatography with Electrochemical Detection (LC-EC)

W. A. MacCrehan

Research emphasis in this past year has been focused on the development of new chromatographic separations and the optimization of the

electrochemical detector response.

Following a literature survey by A. Cohen (NBS/CAC), the electroactivity of over 30 currently used organic pesticides was investigated

using current-sampled polarography to provide a basis for their electrochemical detection. A chromatographic separation of six frequently

encountered pesticides (including parathion and guthion) has been developed (see figure 10).

Many possible separation conditions have been evaluated for the

separation of the cationic organotin species, employing such methods as ion exchange and reverse-phase chromatography in the presence of com- plexing agents. Little success has been obtained in this laboratory,

but Brinckman and Jewett have developed a separation for the mono- cationic species, and this separation was used to evaluate the electrochemical detection approach. The amperometric detection of tri phenyl tin

76
Log

I

Figure 9. Linear correlation of LC retention data (Log I) and the length-tobreadth ratios for methyl benzo[c]phenanthrenes (»), methyl

benz[a]anthracenes (X), and methyl chrysenes (•).

77
cation was complicated by the formation of an electrode deactivating

film of hexaphenyldi tin. This problem was overcome using pulsed detection

wave-forms which take advantage of the electrochemical reversibi 1 i ty

of the reduction (see figure 11).

A comparison has been made of several materials for the working

electrode of the detector cell. A dropping and hanging mercury electrode

cell, as well as several solid-electrode thin-layer cells (based on mercury-coated gold, platinum, and glassy carbon), were evaluated for

their negative potential range and detection limits for reducible

organic pesticides. A manuscript on LC-EC has been submitted to Analytical Chemistry.

a. Development of a High-Sensitivity Dual -Electrode Detector for

Liquid Chromatography

Reductive electrochemical detection in liquid chromatography (LC)

is potentially a very powerful measurement technique in the determination of trace organic pollutants by virtue of its sensitivity and

selectivity. However, for the best sensitivity, oxygen exclusion is

required. This makes the technique cumbersome to use and has restricted

its application.

A new approach for reductive LC detection that eliminates the need

for complete oxygen exclusion has been developed, A two-electrode,

thin-layer cell is used in a manner conceptually similar to a ring-disc

system. Two closely spaced electrodes are poised at different potentials. The first electrode encountered by the flowing electrolyte is

held at a potential sufficiently negative to reduce the analyte. The

second detector electrode is held at a potential sufficiently positive

to reoxidize the generated species and also to avoid the reduction of

oxygen. The low residual current at this potential assures a low

background noise, upon which the analytical current is easily measured

with high sensitivity.

The best analytical response is obtained for analytes that either

are reversibly reduced or that have chemical followup reactions that

generate easily oxidized products. The reductive/oxidative behavior of

three important industrial /environmental pollutants - nitrobenzene,

dichlone, and tributyltin - have been studied by reverse pulse voltammetry.

The sensitivity and linearity of the dual electrode technique has

been evaluated by comparison to direct reductive detection. Two chromatograms

with equal concentrations are pictured in figure 12. The baseline noise

of direct reductive detection without use of an inert atmosphere box is

apparent (upper figure). The lower chromatogram shows the very low

baseline noise of the dual electrode approach achieved with a minimum of

difficulty.

Current experiments involve the evaluation of the technique's

selectivity by application to the measurement of organic analytes in

environmental samples. Also, investigation is in progress on the use of

modulated waveforms and phase selective detection to improve selectivity.

78
Minutes

SEPARATION OF SOME INSECTICIDES

Column: Spherisorb ODS, 5 pm, 4.6 x 250 mm

Soluent: 60% Me0H/H9 0, 0.12 mol/L NH.OAc

1 .5 mL/rnin

Detector: Amperometry -0.85 V, HMDE

Sample: 20 pL of 10 5 mol/L (about 3 ppm) of each

Figure 10. Reverse-phase insecticide separation employing

amperometric detection.

79
Amperometric

Defection

-0.80 V

Pulse

Detection

-0.65 V, 150 mV pulse height

0.5 s Pulse Period

Differential Pulse

Detection

-0.65 V, 100 mV pulse height

0.5 s Pulse Period

Minutes

Figure H- Detection of tri phenyl tl n cation using different detector

waveforms

.

80
Oxidation at + 0.08 V

(Second Eectrode)

4 8 121620

Inject 20^L Minutes

of 10-5 moi/l

Cl

Cl

Figure 12. Different Reductive Detection Modes. Conditions: Analytes--

1.0 x 10~ 5 mol/L of nitrobenzene and dichlone; Solvent--60

percent Me0H/H 2 0, 0.1 mol/L NH 4 0Ac pH 5.2 at 1.0 mL/minute;

Col umn--Whatman Parti si 1 PXS 5 pm. Upper figure--di rect

reductive detection at -0.8 V without enclosure of the LC

in an inert atmosphere box. Lower figure--dual electrode

detection, -0.8 V on generator electrode, +0.08 V on detector

electrode.

81
5 - Development of a Fourier Transform Infrared Spectrometer-Gas

Chromatograph Interface and Its Application to Pollutant

Identification

S. N. Chesler, F. R. Guenther

Installation of a Nicolet 7000 Fourier transform infrared (FTIR)

spectrometer was begun in September 1979, and essentailly completed by

January 1980. The instrument was found to meet all design specifications and even exceed some, such as resolution and signal-to-noise

ratio. The instrument is being used for four distinct research and/or

service functions: high-resolution low-pressure gas work, liquid samples,

liquid chromatography , and gas chromatography

.

The studies of gas chromatographic applications have progressed

through the utilization of packed column chromatography to the construction

and testing of an interface for wall coated open tubular gas chromatographic

columns (WCOT), which will allow real-time FTIR analysis of compounds

eluting from the WCOT. The use of packed columns was not pursued

because they were not found to have the resolving power required for the

separation of the complex samples we wished to analyze. The WCOT columns

used in this project were chosen to maximize sample capacity of the

column, since the FTIR instrument requires ^1 00 ng of component for the

collection of a reasonably identifiable spectrum. Also, an on-column

injector was fabricated to facilitate injection of a maximum amount of

sample onto the column without undo loss of efficiency. The first

interface design consisted of a Pt/Ir tube which connected the output of

the thermal conductivity detector (TCD) to the FTIR light pipe. This

interface was found to be unsuitable because too much dead volume (located

mostly in the TCD and connecting fitting) caused unacceptably peak

broadening. In addition, the Pt/Ir tube thermally trapped out and/or

reacted with all solutes boiling above 300°C.

The present interface consists of a 50 cm length of deactivated,

methyl silicone-coated quartz capillary of 0.15 mm internal diameter.

The TCD has been bypassed and no other gas chromatographic detectors are

used. This interface is connected to a glass WCOT by use of AgCl

cement; if a quartz WCOT were used, then the last 50 cm of the capillary

itself could act as the interface. The quartz interface does not appear

to react with or retard eluting compounds and spectra have been obtained

for compounds such as methyl dibenzanthracene (b.p. <500 °C). Reconstructed gas chromatograms (from IR data) still show large losses in

efficiency over those obtained from normal gas chromatographic detectors. This loss is most likely due to the large volume of the FTIR

light pipe, and a new low volume light pipe is being procured. Even

though the FTIR data does not fully reflect the high-efficiency separations obtained on the WCOT columns, very recognizable and identifiable spectra are being obtained from environmental samples being

analyzed (e.g., phenols in shale oil, PCB's, etc.). This is, to a large

extent, being made possible by some newly developed manipulative com- puter software which numerically regains some of this lost column

efficiency.

82
6 . Laser Analysis of Pollutants in Cryogenic Matrices

J. Stephenson, D. King, M. Jacox

Scientists in the NBS Center for Thermodynamics and Molecular

Science (CTMS) have designed and completed the first stage of testing of

a molecule specific measurement technique for the analysis of complex

environmental samples for evaluation or compliance with EPA standards.

In the past several years it have been recognized that realistic legislation impacting environmental quality must be targeted at a small

number of potentially harmful chemicals, rather than gross regulation

of, for instance, total organic carbon. Of the existing techniques, the

computer controlled gas chromatograph-mass spectrometer system is the

most powerful in terms of sensitivity and specificity. A high degree of

sensitivity is required since many of these regulated chemicals have

toxic or carcinogenic effects at levels in the ppt level; specificity is

required since in many cases the toxicity of a given chemical species

may vary as much as several orders of magnitude between isomers. This

is particularly true for the dioxins.

The laser technique offers a quantiative sensitivity comparable to

that obtained by state-of-the-art GC-MS systems, a much higher degree of

selectivity, and should, when fully implemented, be suitable for certification of environmental SRM's and performance of referee- type mea- surements. This technique involves laser Raman scattering from molecules

isolated in a cryogenic matrix. Raman spectroscopy provides a valuable

fingerprint of the vibrational modes of the molecules present allowing

for identification based on comparison to a library file of known spectra.

Since the molecules are physically trapped in an inert matrix, there is no interference in the Raman spectrum of the first species due to the

presence of a second or other species, the signals from a complex mixture such as expected from real environmental samples Is simply the sum

of the individual components.

To date, NBS scientists have successfully demonstrated the potential sensitivity and selectivity of this sytem in the analysis of laboratory samples of complex mixtures of volatile organic species at the

sub nanogram level (corresponding to recapture of environmental samples

at the ppt level). In_these studies isomeric species were readily

resolved with a 0.3 cm” 1 resolution (isomeric peaks often show Raman

shifts of 10 -50 cm” 1 ). The group recently acquired an LSI-11 controlled

optical multichannel analyzer (OMA) and commercial gas chromatograph and

have refabricated the sampling system to provide for higher sensitivity

and sample thru-put and to allow analysis of real world samples.

The status of this work is now at the point that within 6 months our operative system should be ready for the acquisition, separation and

analysis of environmental samples. Considerable help was received from

colleagues at Argonne Laboratory. The initial tests of this system will

include analysis of laboratory and real world samples of the tetrachlorodibenzo-dioxin isomers which cannot currently be distinguished by

any existing technique at any concentration.

83
(2) Methods Development for Inorganic Analysis

Participating Staff: Center for Analytical Chemistry

Background/Objecti ve

In order to evaluate the environmental impact of expanded or new technologies, measurement techniques and monitoring systems are required in the development of a compatible data base to evalute

the total effects of energy development upon our environment and to

make rational policy decisons. Measurement techniques are either

inadequate or do not exist to characterize and/or determine the low

concentration levels of inorganic pollutants. Advanced measurement

methods and instrumentation need to be developed to enable accurate

measurement of energy related pollutants, as well as, data quality

assurance of special field studies and analyses related to levels

of pollutants injected into the environment.

The activities in this project focus on the development of mea- surement methods and instrumentation to enable the analysis of

trace inorganic pollutants. Research efforts are also directed

toward the development of measurement methods to distinguish forms

(speciation) of inorganic pollutants in effluents in order to

assess the transport, transformation and distribution of Inorganic

pollutants in the aquatic environment.

FY-1980 Milestones

° Complete trace elemental study of the 51 sampled sites throughout

the Chesapeake Bay (top and bottom water column).

° Develop measurement methods to distinguish forms (speciation) of

inorganic pollutants associated with energy related effluents.

Selected Technical Highlights

1 . Trace and Toxic Elemental Study of the Chesapeake Bay

H. M. Kingston, R. R. Greenberg, E. S. Beary, T. C. Rains

As part of a multidisciplinary study of the Chesapeake Bay, the

National Bureau of Standards (NBS) was asked to develop the techniques

and procedures necessary to measure the trace and toxic element concen- trations within the water column throught the entire length of the Bay.

As part of this program, NBS collected 102 separate water samples and is

currently completing the analysis for selected elements (Cd, Ce, Co, Cr,

Cu, Fe, Mn, Mo, Ni , Pb, Sc, Sn, Th, 238U, 235 U, and Zn), including some elements at concentrations consistently below one pi cogram per milliliter

(part per trillion). The collection of the samples was described in

the 1979 Center for Analytical Chemistry Technical Activities, however,

the list of elements to be analyzed was upgraded this year to its present

complement with the addition of Ce, Sc, Th, and U.

The literature on marine water analysis reflects the considerable

difficulty in establishing an accurate and precise method of analysis

for trace metals. An estuarine or sea water matrix defies a simplified

approach. The extremely low trace concentrations cause the sample and

84
analytical blank to be of paramount importance. The integrity of the

sample can be compromised by just a brief exposure to normal laboratory

air. In addition, the extremely high concentrations of alkali, alkaline

earth, and halogen elements in the marine water matrix make direct

analysis difficult or impossible for most analytical techniques.

To circumvent these problems, special chemical and instrumental

procedures were developed. While the chemical separation and preconcentration was completed in late 1979, it was recently optimized for

neutron activation analysis (NAA). The basic chemical procedure was developed and published in open literature in 1978 and 1979. The

chemical procedure was substantially unchanged as reported for use with

thermal device atomic absorption (TDAA). However, the elements were not

eluted from the resin when used in conjunction with NAA. Both the

modification and the established procedure proved to be extremely

advantageous when applied to estuarine or seawater analysis.

The elimination of matrix elements allows the determination of many

elements which could not otherwise be analyzed and enhances the sensitivity of other elements of interest. The control of the blank in this

procedure has enabled its contribution to be sufficiently low that it

does not limit the measurement of pristine samples. The particular

fraction of each sample was prepared in the field by splitting a twoliter sample into two one-liter filter samples, one for TDAA and a second for NAA to eliminate handling and dividing a single particulate

sample.

Both the samples and the blanks have undergone rigorous statistical

scrutiny and are being reported after correction for blank contribution

(where necessary) at the 95 percent confidence limit.

It was necessary to extend the capabilities of the chemical and

instrumental techniques to obtain state-of-the-art concentration data

for the samples. All of the elements of interest cannot be analyzed by

a single instrumental technique. The methods necessary to analyze the

estuarine and seawater using NAA have been developed this past year. The

combined use of NAA and TDAA provides the capability to determine a wide

range of important trace elements in estuarine samples. It was found

that by drying the resin in the column after chemical separation and

analyzing it directly in heat sealed polyethylene film that NAA could

simultaneously analyze many elements at the ultratrace level with a high

degree of accuracy. This detailed technique will be published in the

open literature in the near future.

These concentration measurements will be used as the basis for

several studies. Because the samples were taken concurrently with

sediment, pore water, and benthic studies, both the water-to-sediment

equilibrium and aquatic population will be correlated. Beyond this, a "state-of-the-Bay" is being established which includes an estimate of

the impact of the population area impinging on it. The ultimate goal of

the program is to produce an informative study to guide the management

of the Bay. To meet these demands, it is necessary to compare the

results respective of their location throughout the Bay. The interpretation of the concentration data obtained at the different locations

85
throughout the Bay is extremely difficult. At a single location the

concentration can vary with time, tide, current, wind conditions, temperature, biota, etc. With these perturbations of concentration at a single location, interpretation of the differences found at separate

locations is formidable. One approach which has proven useful in minimizing fluctuations is the comparison of elemental ratios rather than

absolute concentrations. For this technique to be successful, however,

the elemental concentration must be determined with a high degree of

accuracy. Reference elements must be chosen which are ubiquitous and

essentially nonanthropogenic. An increase in the total mass loading

will increase the absolute concentrations, but will not affect the

elemental ratios. A significant addition of a single element or several

elements to the environment from either natural or anthropogenic sources

will increase the ratios of this (these) element(s) with respect to the

reference element. Increases in concentration, however, may not be

obvious over the normal fluctuations of the absolute elemental con- centrations. This technique has been applied to the elemental con- centrations in the estuarine samples with dramatic results. The elemental concentrations in the particulate fractions were found to vary

over two orders of magnitude between locations as indicated in Table 15 • The ratios for Fe, Th, and Ce are essentially constant, differing by

only 20 percent, while the Co to Sc ratio is four times greater in

sample 11,032 than in either 11,005 or 11,007.

Table 15. Concentration on Particulate Phase and Ratios to Scandium.

Sample Number

11 ,005 11 ,007 11 ,032

Element Concentrati on--ng/mL

Fe 2,800 ± 100 128 ± 8 18 + ; 1

Co 1.02 ± 0.05 0.050 ± 0.003 0.028 + 0.003

Sc 0.90 ± 0.005 0.040 ± 0.002 0.0049 + 0.0002

Th 0.66 ± 0.03 0.032 ± 0.002 0.0038 + 0.0005

Ce 6.0 ± 0.3 0.26 ± 0.01 0.039 + 0.003

Ratio to Scandium, [X]/[Sc]

Fe 3.2 x 10

3 3.2 x 10

3

3.7 X 10

3

Co 1.1 1.3 5.7

Sc E 1 El E 1

Th .73 00 o

CO

Ce 6.7 6.5 8.0

86
This technique provides a means for identifying the similarities

and differences between the sample locations. A comparison of ratios

throughout the Bay may be useful in identifying anthropogenic and/or

naturally occurring sources to the Chesapeake Bay. If the concentrations

of toxic elements are found to be excessively high. It is necessary to

identify their sources before any attempt can be undertaken to reduce

these levels.

2. Sulfur Speciation in Coal

S. Hanamura

This methodology is based on the measurement of the characteristic

vaporization temperatures at atmospheric pressure of the various forms

of sulfur, using plasma emission spectrometry to monitor each vaporized

sulfur species. The resulting spectrometric thermogram consists of a series of relatively broad peaks, each peak being a different sulfur

species

.

For this experiment, the 1900.27 $ sulfur atomic emission line was used with a HTV R-919 photomultiplier tube and a one-meter monochromator

with air purging. This system, using the 1900.27 A line can detect 100

yg of sulfur. If air is purged and the 1826.25 a line is used, the

detection limit can be lowered to 5 yg. Previously, three sulfur

species in coal have been reported in the literature, pyritic sulfur

(FeS 2 ), sulfate sulfur (FeS0 4 )» and an "organic" sulfur. In the present

experiments, sulfur and iron emission intensities were monitored as a function of temperature.

From these experiments, four sulfur species have been found,

FeS 2 , FeS04 , organic sulfur, and a low evaporation temperature sulfur.

This low evaporation temperature sulfur starts to evaporate at 28 °C.

SRM 1635 Western Coal has been found to contain about 18 times more of

this species than SRM 1632a Penn Coal. Also, organic sulfur has been

found to be linked with iron. In a previously described analytical

technique, organic sulfur was calculated by substracting pyritic and

sulfate sulfur from the total. Therefore, the value obtained from the

"organic" sulfur species included the low evaporation temperature

sulfur. In the future, an attempt will be made to identify the chemical

forms of these species using thermal separation and a cold trap collection technique. Also, an investigation will be undertaken in which

two monochromators are used simultaneously to detect both sulfur and

iron or any other elements which may be bound with sulfur.

Sulfur species analysis still needs work on the development of a standardization procedure, but it is a simple technique and has potential

for the direct determination of each species present.

87
3. Ionic Chromium Speciation Measurements

J. D. Messman, T. C. Rains

An anion-exchange method has been developed for the separation of

tri valent and hexavalent forms of chromium in synthetic aqueous solutions. The aqueous sample is made IN in HC1 and is then introduced onto

the anion-exchange column. In a IN HC1 medium, Cr (III) elutes from the

column while Cr (VI) is adsorbed by the active sites of the anionexchange resin. After Cr (III) has eluted from the column, a solution

of IN ascorbic acid in IN HC1 is added to the column which then reduces

the Cr (VI) species to Cr (III) species directly on the column. The

newly-formed Cr (III) species are then eluted from the column as in the

first part of the procedure. Atomic absorption spectrometry is used for

on-line detection of the chromium species as they elute from the column.

The aspiration uptake capillary of the AAS nebulizer is replaced by a Teflon microsampling cup. The anion-exchange column is positioned so that the eluent drops directly into the microsampling cup for continuous

nebulization and atomization of the sample. A chromatogram which

illustrates the direct speciation of tri valent and hexavalent chromium

by ion exchange-atomic absorption spectrometry (IE-AAS) is shown in

Figure 13 .

88
Absorbonce

Figure 13

89
AIR MEASUREMENTS - STANDARDS DEVELOPMENT

a. Overview

The national program for assessment and abatement of pollutant

emissions to the atmosphere is predicated on concerns for the known or anticipated detrimental effects of such emissions on human health and

the environment. National legislation mandates that emission assessments

be performed by monitoring air pollutant concentrations from stationary

and mobile sources. Such activities involve a broad spectrum of measurements carried out by municipal, state and federal agencies, and by the

industrial sector. In order to assure the quality and intercomparability

of data over this broad measurement community, highly reliable standards

are needed. This Task addresses the development of high priority research

standards and Standard Reference Materials (SRM's) to assist attainment

of national program data quality in air pollution monitoring.

Objective

To develop priority research materials and SRM's that provide data

quality assurance in national air pollution monitoring programs. This Task

covers the development of national standards for air pollution assessments

required by current legislation. Activities in this Task are represented

by topics such as ambient and stationary source gases, asbestos, urban air

particulates, trace inorganic and organics in particulates, and organic

gases.

Interactions

This program strongly interacts with the Office of Standard Reference

Materials, OSRD, with various Centers (CAC, CTMS, CRR, CMS, CAM). The

activities within this Task involve direct interactions between the

involved technical and managerial staff of NBS and relevant staff com- plements within other agencies, such as the U.S. Environmental Protection Agency (under EPA/NBS Interagency Energy/Envi ron-mental Agreements).

Strong interactions also exist with industry, state and local government

agencies, research laboratories and universities. Related NBS R&D

activities regarding the improvement or innovation of methods having

potential or actual application to the establishment of RM's or SRM's

for data quality assurance of air pollutant measurements are closely

followed.

Task Justification

Development of quality assurance reference standards is essential for

valid air quality monitoring data to address the attainment of national goals

for the public health and welfare, and for the concomitant assurance of a viable ecological environment. This program directly impacts the meaningful

assessment of airborne pollutants and national air quality. The activities

of this program are required, provided under, or have been recommeded by the

Clean Air Act, its 1977 Amendments, The Standing Air Monitoring WorkingGroup,

the Council on Environmental Quality, the Interagency Task Group on Environmental Data and Monitoring, the Toxic Substances Control Act, and the NBS

Organic Act.

90
b. List of Projects

Project Title Source of Funding*

Asbestos in Air P/T - EPA

T oxic Organics - Air P/T - EPA

Acid Precipitation Stds. P/T - EPA

Air Generator Columns P/T - EPA

Ozone Photometers P/T - EPA

Gas Standards E/E - EPA

Particulate Standards E/E - EPA

*P/T : Pass Through - E/E: Energy/Envi ronment

91
AIR STANDARD - PROJECT DESCRIPTIONS

(1) STANDARD REFERENCE MATERIAL AND REFERENCE METHOD FOR ASBESTOS IN AIR

Participants : John Small, Eric Steel, Patricia Johnson,

Patrick Sheridan

Goal

To assist EPA in improving the reliability of measurements of

asbestos fibers in air by providing standards for calibration

and measurement and reference measurement technology.

Objectives

0 Provide calibration standards to be used for the determination

of relative sources of error in EPA's Analytical Electron Microscopy (AEM) provisional reference method, for laboratory and

field evaluation of the reference method, and for interlaboratory

collaborative testing.

al 0 Provide a laboratory evaluation of key procedural variables in

the provisional reference AEM method, and recommended optimized

procedural parameters.

Technical Approach

The major objective of this program will be to develop and provide

calibration standards consisting of asbestos fibers dispersed in an appropriate matrix and deposited on a filter substrated. These standards

will be designed for use in a quality assurance program to improve and

maintain the reliability of measurements of asbestos fibers in the

ambient atmosphere. A secondary objective will be to utilize the

competence and facilities at NBS to evaluate key procedural variables in

EPA's provisional reference method.

The development of an asbestos standard of the quality and quantity

required for an NBS certified Standard Reference Material (SRM) would

require a considerable length of time. Research materials will be

provided in a limited quantity in order to satisfy the interim requirements

for conducting methods evaluation, field testing, and interlaboratory

comparisons. The interim research materials, by definition, will not be

NBS SRM's certified in terms of fiber count or homogeneity on the filter,

but the fiber count and homogeneity data provided with the research

material will be the best attainable within the time frame of the

milestones in Part F. Limits of error will be provided by counting

statistics for fiber count and degree of sample homogeneity. The re- search materials provided in FY-79 and early FY-80 will be assayed for

fiber count only. Information on size distribution, and identification

of fiber mineralogical group will be provided at a later date. The work

performed in developing these research materials will provide the basis

for the ultimate provision of NBS asbestos fiber SRM's.

92
The limited amount of research materials provided during FY-79 will

be developed by borrowing time on an AEM. An NBS dedicated AEM will be

required in order to undertake a variety of activities associated with

this program. Optimization of the AEM would require modification not

permissible on a non-NBS system. The NBS AEM will be used to provide:

0

the inclusion of amphibole fibers with chrysotile, with

quantitative information on both fiber types.

0 quantitative information on fiber size distribution.

0

more substantial amounts of research material.

0 the ability to evaluated key parameters in the EPA AEM

provisional method.

0

a detailed examination of urban airborne particulate as a filter matrix.

0

support analyses of filter samples for EPA.

The FY-79 program is summarized as follows:

0 Counting grid standards for the AEM will be prepared and

analyzed. These will be electron microscope grids on which

NIEHS short chrysotile fibers have been dispersed in an appropriate matrix. These grids will be useful in evaluating

the statistical counting portion of the EPA provisional

method, and will provide a means for experimentally analyzing

counting statistics and the ability of operators to distinguish

fibrous versus non-fibrous material.

0

In order to evaluate the complete procedure (including sample

preparation), chrysotile fibers dispersed in a suitable matrix,

preferably urban air particulate (UAP), will be deposited on Millipore or Nuclepore filter paper. Mechanisms will have to be

developed to attain homogeneous dispersal and deposition of the

fibers and the matrix on the filter. A statistically-designed

plan will be developed in order to define the level of counting

required for the determination of fiber density and homogeneity

on the filter.

0

NBS, in collaboration with EPA, will define and prioritize key

procedural parameters in EPA's AEM provisional method that

require laboratory evaluation and optimization.

93
Description of Initial Project Activities

0 Investigation of Mechanisms for Fiber and Matrix Mixing

Dispersal, and Filter Deposition

The filter research material and the filter calibration

material will requie a uniform deposit of chrysotile fibers

and matrix material on a filter. A liquid suspension will

be used, and a variety of liquids, surfactants, and agitation

techniques will be investigated to determine the best combination for uniform deposition.

Two approaches to mixing the NIEHS chrysotile fibers with the

matrix material will be tested. One method is to combine the

two in a liquid suspension before filtering; another approach

is to use a two-step filtration--fir$t filtering a suspension

of chrysotile, then filtering a suspension of matrix material,

onto the same filter. Other parameters that may have adverse

effects on the homogeneity of the deposit (such as erratic or

high background levels of chrysotile from blank filters) will

also be studied.

0 Preparation of Asbestos/Carbon Grid Sample

The operator counting error needs to be determined statistically

before a reference filter can be fully characterized. In order

to do this, some of the preliminary filters developed in A. above will be mounted on a TEM finder grid using a carbon

coating and the Jaffe wick filter dissolution technique. Three

concentrations will be used to mimic the range of conditions

found in typical samples.

The loadings will be approximately 5-10 fibers per grid-square,

25-50 fibers per grid-square, and over 100 fibers per gridsquare. These grids will be counted by several operators,

and the fiber count for each marked grid-square will be recorded.

Statistical evaluation of these data will be used to determine

operator variance.

0 Preparation of Asbestos/Matrix Research Material

The knowledge gained in the previous steps will be combined to

prepare a series of filter research materials with low, medium,

and high loadings, having a defined distribution of fibers

deposited onthe filters.

0 Evaluation of the EPA AEM Provision Method

In collaboration with EPA personnel, we will identify

critical variables in EPA's provisional AEM method which

need laboratory evaluation. This evaluation will begin once the NBS AEM is operational.

94
Project Milestones and Estimated Completion Dates

1. Complete counting grids research materials: NIEHS

short fiber chrysotile in unambiguous synthetic

matrix (CaF

2

). (Completed)

2. Initiate identification of key parameters in AEM

provisional method for detailed evaluation. (This

milestone was initiated 6/79 and will continue

throughout program).

3. Install and accept NBS AEM system. (Completed for

1st phase of program on chrysotile).

4. Complete counting grids research material: NIEHS

short fiber chrysotile in a particulate matrix

(UAP) - fiber count. (Completed - additional grids

will be delivered to RTP as they become available).

5. Complete NBS AEM analysis of Urban Air Particulate

(UAP) for use as a certified matrix. (Completed for

phase 1 (chrysotile) of program; characterization of

amphibole and other fibers is continuing).

6. Analyze up to a maximum of 50 filter samples (light

to medium loading) for EPA using EPA and/or NBS

analysts

.

7. Develop a coordinate location system on AEM for

fiber mapping and concentration verification.

(Completed)

8. Hold NBS/EPA Asbestos Standards Workshop at NBS.

(Completed)

9. Complete two Nuclepore "analyzed" filters with a light loading of chrysotile in UAP matrix (20-40

fibers/grid opening).

10. Complete two Nuclepore "analyzed" filters with a medium loading of chrysotile in UAP matrix (40-70

fibers/grid opening).

11. Report on summary of recommendations developed

from NBS/EPA Asbestos Standards Workshop (held

at NBS, 10/80).

12. Complete NBS AEM analysis of Urban Air Particulate

for use as a matrix for the Characterization of

amphibole fibers.

9/79

6/79

8/79

3/80

6/80

To be

determined

9/80

10/80

12/80

11/81

2/81

3/81

95
13. In cooperation with EPA conduct an intermediate

round-robin study making use of the "analyzed"

filters from milestones 9 and 10. 4/81

14. Initiate a proposal to Office Standard Reference

Materials for the issuance of asbestos Research (RM)

or Standard Reference Materials (SRM). RM/SRM to

contain chrysotile in UAP matrix. 4/81

15. Develop the set of materials to be used for the

RM/SRM. 5/81

16. Perform measurements leading to certification of

RM/SRM. 7/81

17. Complete two Nuclepore "analyzed" filters with a light

loading of a mixture of amphibole and chrysotile

asbestos in UAP matrix. 7/81

18. Complete two Nuclepore "analyzed" filters with a medium loading of a mixture of amphibole and

chrysotile asbestos in UAP matrix. 8/81

19. Complete counting frid research material. NIEHS

short-fiber chrysotile in a particulate matrix

(UAP) - fiber count. Deliver up to 10 additional

grids. 9/81

20. Complete amphibole counting grid research material,

crocidolite or Amosite asbestos in UAP matrix, to

be used for fiber count and identification. Up to

10 grids to be delivered. 9/81

21. Issue special publication as a result of NBS/EPA

Asbestos Standards Meeting. 9/81

22. Issue RM/SRM Nuclepore filters containing

chrysotile in UAP matrix. 12/81

23. In cooperation with EPA conduct an intermediate

round-robin study making use of the filters

from milestones 17 and 18. 12/81

24. Initiate a proposal to Office of Standards

Reference Materials for issuance of asbestos

RM/SRM. (amphibole/chrysotile mixture) T/82

25. Develop the set of materials to be used for

RM/SRM. (amphibole/chrysotile mixture) 2/82

96
26. Perform measurements leading to certification

of RM/SRM mixture. 5/82

27. Issue RM/SRM Nuclepore filters (mixture). 8/82

28. Perform work necessary to issue heavy loading

filters greater than 70 fibers/grid opening. 9/82

29. Complete evaluation of EPA provisional method. 9/81

30. Conduct round- robin evaluation of EPA provisional

method making use of the certified materials. 9/82

Project Progress - FY-1980

(a) Project Synopsis :

Initial work in FY-1980 focused on chrysotile asbestos fibers on filters, evaluation of the NBS Urban Air Particulates SRM (#1648) as a useable urban air particulate matrix, and to various aspects of progress

working with fiters. In corrdi nation with the NBS Center for Applied

Mathematics, we analyzed counting data, representing approximately 150

grid squares at about 40 fibers per grid square. With this information,

assessments were made of the operator error associated with measurements

of asbestos on filter samples. This assesssment is critical to determining

the level of accuracy with which a fiber concentration on a research

material filter can be reported. In addition, fiber counting is a major

parameter of the EPA Provisional Method for asbestos in air measurements

under collaborative evaluation with EMSL/RTP. Preliminary studies of

the potential loss of small fibers using the Provisional Method's 0.4 pm

filter relative to a 0.1 ym filter, and homogeneity evaluation of fiber

deposition on Nuclepore filters, were also carried out.

Work has progressed well on the preparation and counting of chrysotile

asbestos fibers in an urban particulate matrix. It was determined that

the NBS Urban Particulates SRM (SRM #1648) was a usable air particulate

sample for this purpose. In addition, counting grids of chrysotile

asbestos in a fluorite matrix were forwarded to EMSL/RTP for distribution

to non-EPA laboratories for evaluation. Further, deposition homogeneity

of chrysotile asbestos in an urban air particulate matrix on Nucleopore

filters was evaluated. Finally, a workshop, titled "NBS/EPA Asbestos

Standards Workshop," was held at NBS October 1-3, 1980, jointly sponsored

by EPA and NBS. Announcement letters were sent out to approximately

thirty-five individuals involved in asbestos analysis from a list jointly

compiled by EPA and NBS.

Data were collected on operator error and filter homogeneity for

prepared samples of chrysotile asbestos in the Urban Particulates SRM

(#1648) deposited on a 0.4 ym nuclepore filter. Histograms of asbestos

fiber counts appears to fall between a normal and a uniform distribution

for a given filter. A geographic analysis of the fiber distribution on

97
the filters was carried put. The errors of five operators at NBS are now reasonably well defined, and usually fell in the ± 5-10% relative

error range. Further definition of this error was possible using a device that allows the position of each fiber to be determined. Three

counting grids were delivered to M. Beard (EMSL/RTP) in April. Interlaboratory error studies were initiated using these counting grids.

Characterization of particulates in SRM 1648 continued. Speakers for

specific review papers were invited to the asbestos standards workshop

(see (c) , below)

.

A manual x-y coordinate system employing digital voltmeters for

mapping fiber location within a grid square was completed. The data

collected with this system are used to plot locations of fibers counted

by various operators. Operator countings are then correlated with

respect to fiber locations and verification as chrysotile. The values are used to determine a verified count for a given grid opening. Plots are used to quantitatively and accurately compare operator counting

abilities. Fiber counts on 38 grid openings, representing areas se- lected from the major portion of a filter surface, are under analysis by

the NBS Center for Applied Mathematics. Preliminary results have indicated

fiber distribution can be described by a Poisson distribution. Final

planning is underway for distribution of Research Material filter segments

to several laboratories for analysis. A round- robin analysis involving

a number of principal asbestos analysis laboratories has also been

planned.

(b) Evaluation of Counter Error in the Development of Asbestos

Standards for the Electron Microscope - Interim Report

The Environmental Protection Agency has been monitoring the concentration

of asbestos in ambient air, because of its potential adverse health

effects, using an electron-microscopic anal of filtered air particulates. During a number of interlaboratory studies, EPA found that the

reported asbestos concentrations varied among laboratories by up to five

orders of magnitude on the same filter. Many laboratories consistently

reported relatively high or low results, in part due to operator bias or

error, filter inhomogeneity and counting statistics. Generally, because

of the high magnifications used during analysis, only approximately

1/100,000 of the total filter area was observed. The data from this

small area were then extrapolated to the whole filter to determine the

relative concentration.

Because of these problems with asbestos analysis, EPA requested NBS

to prepare filters with known asbestos fiber concentrations that are homogeneous on the level of a ym

2

. In attempting to approach as closely

as possible the true asbestos fiber concentration on the filter NBS has

used up to five microscopists to analyze the same areas of filters.

These areas were then sent to other experienced laboratories for analysis.

The results are shown in Table 16. The variability of these counts both

within NBS and at other laboratories was considered excellent by EPA.

98
But these results could not be correlated to determine where the errors

in analysis occurred. Also, it was felt that an average or mean value

as reported in column 1 of this Table for the five NBS operators was not

necessarily an accurate description of the number of fibers on the areas counted. For these reasons a digital specimen positioner was designed

at NBS so that individual fibers could be uniquely identified by their

X-Y coordinates. Three to five NBS operators counted the same 75 ym x 75 ym area, recording each fiber's X-Y position. The counts were then

correlated, and finally the area was reanalyzed to verify all fibers.

In this way it was felt that the verified fiber count was as close as possible to the true concentration. Table 17 shows some of the data

recently collected using this method. This Table shows each operator's

error as number of fibers counted and how many of these were incorrect

counts, how many fibers were missed, and the verified concentration.

Knowing the error associated with the five NBS operators and using

the verified fiber counts has allowed work to proceed in characterizing

fiber distribution and concentration towards a final product, an asbestos

filter standard.

(c) NBS/EPA Asbestos Standards Workshop

Following is a listing of the Workshop program. A questionnaire

has been developed on the Workshop and sent to participants in order to

develop the final Workshop recommendations. These finalized recommen- dations will be submitted to EPA for review and consideration. A

published Proceedings of the Workshop is planned, covering the full

manuscripts of the twenty-three talks presented.

Introduction :

"Quality Assurance for Airborne Asbestos Measurements"

M. Beard (EPA)

Session I - Bulk Materials for Preparation of Asbestos

Standards

:

"Asbestos Reference Materials: Sources and Characterization" -- R. Draftz (IITRI)

"Glass as a Material for Asbestos Standards"

D. Cronin (NBS)

"NBS Standards Program"

K. Kirby (NBS)

"Analysis of NBS SRM #1648 for Use as a Matrix Material

in the Development of Asbestos Filter Standards"

J. Small (NBS)

"Bulk Standards and Their Relationship to Polarized

Light Microscopic Analysis of Asbestos Containing

Materials" -- R. Virta (BOM)

"Preparation of Asbestos Standards for Methods Vertifi cation

and Laboratory Evaluation" -- D. Lentzen (RTI)

99
Session II - Standards Preparation:

"Sample Preparation for Quantitative Electron

Microscope Analysis of Asbestos Fiber Concentrations"

P. Cook (EPA-Duluth)

"Development of a Waterborne Asbestos Reference

Material

R. Feldman (EPA-Cincinnati/University of Virginia)

"Preparation of Air Standards"

D. Jones (IITRI)

"Concentration and Separation of Chrysotile by Two

Phase Liquid Separation"

C. Melton (Battelle)

Session III - Asbestos Analysis for Standard Certification:

"Analytical Procedures and Standardization for Asbestos

Fiber Counting in Air, Water, and Solid Samples"

E. Chatfield (ORF)

"Automated Particulate Measurements by Image Analysis"

R. Clark (MSHA)

"Development of a Rapid Survey Technique for the

Detection of Asbestos Fibers in Water Samples"

P. Riis (ORF)

"Interlaboratory Measurements of Amphibole and

Chrysotile Fibers in Water"

K. Chopra (Union Carbide)

"Low Fiber Concentration Counting Difficulties"

R. Lee (U.S. Steel)

Session IV - Error Analysis and Statistics:

"Membrane Filter Method: Statistical Consideration"

G. Chase (Johns-Manville)

"Simulation of the EPA Provisional Method for Airborne

Asbestos Concentrations"

T. Fitz-Simons (EPA)

"Minimization of Operator Error in AEM Analysis of

Asbestos" -- E. Steel (NBS)

100
"Asbestos Filter Counting and Homogeneity Error

Analysis and Statistics" -- S. Leigh (NBS)

Session V - EPA Provisional Method:

"Refinements in the EPA Provisional Methodology"

G. Yamate (IITRI)

"Fiber Identification and Blank Contamination Problems

in the EPA Provisional Method for Asbestos Analysis"

S. Ring (Minn. Dept, of Health)

"MSHA Standard Method for Fiber Identification by

Electron Microscopy"

R. Clark (MSHA)
Table 16. A Comparison of Asbestos Fiber Counts from Four Laboratories

for Nine Areas. (Number of Fibers per ^ 75 pm x 75 pm area).

Area

Laboratory (NBS)

(Five Operators) (2) (3) (4)

1 32.6 ± 2.5 23 42 22

2 31 .8 ± 1 .6 32 36 33

3 27.6 ± 1 .5 22 23 22

4 15.8 ± 1.5 16 13 15

5 49.8 ± 4.4 33 32 40

6 51 .0 ± 2.3 37 40 45

7 53.2 ± 3.7 35 39 44

8 53.0 ± 3.5 33 38 42

9 39.0 ± 1 .6 22 30 40

Table Operator Error Data for a 75 pm x 75 pm Area Using a Verified

Counting Technique Based Upon an NBS Designed Speciman Position

Digital Readout.

Operator

Total Fibers

Counted

Fibers Not

Counted

Fibers Incorrectly

Counted

Verified Fil

Counted

1 31 2 7 26

2 24 2 0 26

3 20 8 2 26

4 25 1 0 26

102
(2) STANDARD REFERENCE MATERIALS (SRM's) FOR TOXIC ORGANICS IN AIR

Participants : W. Schmidt, W. Cuthrell

Background

The Toxic Substances Control Act of 1976 focused attention on the need for a better understanding of the effects of chemicals

on human health and the environment. It has been estimated that

70,000 chemicals are currently in use. Although only a small

number of these are toxic, the risk to human health and the

effect on the environment will be the subject of intensive study

during the next five years. Many classes of compounds will be

scrutinized by the EPA. One of the largest classes of compounds

will be organics, which are used widely in industry as precursors

in the manufacture of synthetics and as solvents in various

commercial operations. To identify and measure the concentration

of organics present in the atmosphere, the Environmental Protection

Agency is involved in monitoring programs for organic compounds.

It is expected that the number of such projects will increase.

Essential to a successful monitoring activity is availability of

certified standards materials in the measurement range of interest.

These standards are needed for calibration of the measurement

technique and in quality assurance activities necessary to determine the precision and accuracy of the monitoring data gathered.

Organic standard materials having certified concentrations of

organics are not available for use with air monitoring methodology.

Since the need for standard materials will increase with additional

monitoring activity, development for organic Standard Reference

Materials should be initiated. The logical area for this effort is

the National Bureau of Standards (NBS). NBS already produces

Standard Reference Materials (SRMs) of many and varied types, and

has the facilities and expertise needed. SRM's produced by NBS are characterized over long periods of time before they are added

to the catalog of materials available. Research materials (RM's) are also available from NBS, which have been carefully analyzed,

but are not as extensively characterized as SRM's. New organic

RM's would meet the more immediate monitoring needs of EPA.

103
1

.

Purpose

The immediate purpose of this Task is the development of organic

RM's by NBS for use by EPA in their monitoring and quality assurance

programs. NBS development of SRM's rather than RM's will be considered

separately for each case as needs become identified during the course of

this multi-year program, following EPA and NBS concurrence. These

materials will include toxic organic compounds in compressed gas cylinders,

and in permeation tubes. Analysis is needed on special high priority

materials, such as permeation tubes, cylinders gases, substrates with

volatile organics deposited on them, and for flow measurement. In conjunction with the preparation of toxic gas RM's, toxic gas analytical

methods research will be carried out by NBS to evaluate appropriate

methods or devices for toxic gas standards. NBS will also pursue an initially modest effort in the characterization and quantification of

polynuclear aromatic hydrocarbons on urban particulate dust.

2. Selection of Organic Compounds

Lists of organic chemicals to be tested for toxicity and impact on the environment are being updated by EPA based on new informa tton as it

is gathered. Three EPA lists of toxic chemicals are presently available:

one from the Office of Toxic Substances; one from the Office of Air

Quality Planning and Standards; and one based on ambient air organic

screening projects carried out by EPA. A number of gaseous toxic

organic compounds are common to all lists. Of this number, the following

are considered by EPA as most compatible with development as NBS RM's in

cylinders or permeation tubes: toluene, chloroform, trichloroethylene,

carbon tetrachloride, ethylene di bromide, ethylene di chloride, benzene,

and perchloroethylene. Research materials containing lower volatility

materials, including benzo[a]pyrene, biphenyl, and anthracene, are also

of interest to the EPA.

3. Research Materials (RM's)

Research Materials of the permeation tube or compressed gas cylinder

type will be provided for generation of known gas concentrations in the

range of interest. A teflon permeation tube filled with an organic

compound allows for generation of a range of gas concentrations if the

permeation rate of the tube is known. The permeation rate of the tube

is dependent on a number of factors, including the physical properties

of the permeant, the temperature of the permeation tube, and the thickness of the tube. Permeation tubes have been successfully prepared by

EPA for perchloroethylene, ethylene dichloride and benzene. It is

likely that permeation tubes can also be sucessfully prepared for the

other volatile compounds listed in the preceding section. Permeation

rates of interest to the EPA are in the range of 100 to 1000 ng/min at

25°C. A determination whether permeation tubes can be prepared for each

compound, and subsequent tests for their stability are necessary initial

steps in their certification as RM's. If permeation tubes cannot be

successfully prepared for some of the organic compounds, other approaches

will be considered.

104
Compressed gas cylinders also provide a convenient method for

providing gases in concentrations needed for calibration. The success of

this approach is dependent on, among other factors, the reactivity of

the gas with the cylinder wall, regulators and makeup gas. Concentrations

of some gases in cylinders listed in the above section have been successfully

prepared in the range of 10 ppm, which is the upper concentration range

of interest. The long-term stability of these organic compounds in

cylinders at the 10 ppm range, and below, has not been determined

conclusively. It is important to ascertain the stability of such

organic gases at concentrations in the 5 to 10 ppm range, as well as the

feasibility of preparing stable compresseed gas cylinders in the 0.5 ppm

to 1 ppm range. Some data exists to indicate that benzene and perchloroethylene

have at least short-term stability in cylinders. The first two volatile

organics to be examined as to feasibility will be benzene and perchloroethylene,

since these are representative organic compounds of the volatile aromatic

and halogenated organic toxic materials, respectively, of immediate

interest in this Task.

Gaseous organic compounds deposited on air sampling substrates such

as Tenax or charcoal will be necessary for use as quality control blind

audit samples for EPA field monitoring studies. The long-term stability

of these spiked tubes is doubtful. EPA may request NBS to serve as a reference laboratory to analyze spiked samples prepared by EPA. Such

special analyses would fall under NBS Project (a) (Section C, below).

Percent recovery of organics spiked on substrates has not been clearly

defined for most of the organics listed and this problem will require

resolution.

4. Measurement Capability

A measurement technique will be necessary for each organic compound

listed. Fortunately, gas-liquid chromatography using a flame ionization

(FID) or electron capture (EC) detector may be used to quantitate many

organics. This analysis capability along with more sophisticated techniques not applicable as field methods will be used by NBS to determine

the concentrations of organics in Research Materials. Analysis for

organic compound impurities could be provided by gas chromatography

coupled to mass spectrometry.

The Quality Assurance Divison of EMSL is setting up a gas chromatograph

with FID and EC detectors. This chromatograph will be used in preparation

and analysis of blind audit samples for use in field monitoring projects.

Once this EPA project and the NBS effort becomes operational, an ex- change of spiked samples and working standards may be made.

105
Project Milestones and Estimated Completion Dates

(a) Analysis of Special Materials

0 Evaluate current NBS analytical methodology for

toluene chloroform, trichlorethylene, carbon

tetrachloride, ethylene di bromide, ethylene

di chloride, benzene, and perch! oroethylene and

report to ERA. (Completed) 6/79

0

Procure organics, analyze for purity and prepare

primary standards and standard mixtures. (Completed) 7/79

0 Analyze volatile organics in liquid and gas samples;

check analysis method for linearity of response,

precision, and accuracy. (Completed) 8/79

0 Analyses of test samples provided by EPA. (On-going) FY 79/80/81

0 Conduct reference analysis of special samples

containing toxic organic gases in cylinders; as requested. (On-going) FY 80/81

(b) Development of Toxic Gas Standards

0 Complete evaluation of permeation tubes and gas

cylinders for benzene and perchloroethylene. (Completed) 5/80

0 Obtain permeation tubes for 6 remaining compounds.

(Completed) 5/80

0 Prepare CCl^ and toluene gas cylinders. (Completed) 6/80

0 Initiate study of feasibility of permeation tube

and gas cylinder standards for acrylonitrile. (Completed) 7/80

106
0 Complete ruggedness testing on permeation tubes

and cylinders for long-term stability of benzene

and perch! oroethylene. (Completed) 9/80

0 Complete analytical certification of benzene and

perchloroethylene. (Completed) 9/80

0 Initiate final analysis of benzene and perchloroethylene as RM's. (Completed) 10/80

0

Complete evaluation of permeation tubes and gas

cylinders for CC1, and toluene for stability as RM's. 12/80

0

Issuance of benzene and perchloroethylene as RM's. 9/81

0 Complete evaluation of permeation tubes and gas

cylinders for acrylonitrile and chlorobenzene. 10/81

(c) Toxic Gas Analytical Research

0 Investigate absolute UV photometry for the

determination of benzene in primary gas standards.

(Completed) 9/79

0 Initiate evaluation of Tenax/charcoal for benzene

and perchloroethylene (adsorption efficiency,

break-through rates, recovery, stability).

(Completed) 6/80

0 Complete evaluation of UV photometric method

for the analysis of trace benzene in air/^. 5/81

0

Report on initial experiments involving Tenax/

charcoal for benzene and perchloroethylene. 9/81

(d) Organics on Particulates

0 Extensively characterize St. Louis Urban Dust SRM

for polynuclear aromatic hydrocarbons. (Completed) 7/79

0 Examine different extraction methods for quantitative removal of organic compounds sorbed on particulates. (Completed) 9/79

107
Project Progress - FY-1980

1 . General Progress Synopsis :

A set of six benzene and six perchloroethylene permeation tubes

were equilibrated and calibrated gravi metrically at 25°C. The benzene

tubes were also intercompared using gas chromatography (GC) with flame

ionization detection. A GC comparison of an EPA benzene tube with a calibrated benzene tube indicated the feasibility of this comparative

technique for short term calibrations of benzene tubes submitted to NBS

by EPA. Preparation of initial benzene and perchloroethylene gas mixtures

in cylinders was also been completed. A report on the characterization

of polycylic aromatic hydrocarbons on urban particulates and on evaluation

of extraction procedures was sent to EPA.

A set of four gas cylinder research standards of benzene in air was prepared gravimetrical ly. These standards were compared with a benzene

in air gravimetric standard prepared in May 1979, using gas chromatography

with flame ionization detection (CG-FID). A least squares fit of the

data yielded the following:

Cylinder

Number

FF6976 (May 1979)

X-207055

X-207094

X-207070

X-2Q7099

Gravimetric

Concentration

46.3 ppm

10.4

10.2

5.50

4.87

GC-FID

Analyzed

Concentration

46.3 ppm

10.4

10.2

5.47

4.93

In addition, six permeation tubes of each of six of the other

organics identified by EPA for this project were obtained. Gravimetric

calibration of these permeation tubes at 40°C was also undertaken.

Evaluation of permeation tubes for benzene and perchloroethylene

was completed, as well as evaluation of benzene gravimetric (gas

cylinder) standards for linearity of response. Perchloroethylene gravimetric

standards were prepared and evaluated. In addition, specially-treated

aluminum cylinders were obtained and evaluated for their ability to

maintain sample integrity. A special inlet unit was obtained for flash

heating adsorption tubes for gas chromatographic analyses and a permeation

tube dilution system was developed for generating known concentrations

of organics. Also, gravimetric standards were prepared and are under

evaluation for the evaluation of four muli tcomponent mixtures, as re- quested by EMSL/RTP.

108
A sample of acrylonitrile has been obtained and planning for

preparation of gas cylinder standard is underway. Long-term stability

of benzene and perchloroethylene gas cylinders (6 mos) and permeation

tubes (1 yr) has been demonstrated. Temperature change effects will be

examined as part of the ruggedness testing of these standards. Comparison

of permeation tubes with gas cylinder standards for benzene and perchloroethylene

indicate a correlation with less than M disagreement. Intercomparisons

of the gravimetric cylinder standards shows an uncertainty of M).5%

relative. Multicomponent mixtures have been prepared gravimetrical ly

and are being used to develop G.C. separation procedures as well as to

determine the accuracy of the gravimetric standards procedure. A detailed FY-1980 progress report on this project is being prepared for

EPA.

2. Standards for Measurement of Benzene and Perchloroethylene

in Ambient Atmospheres

The first set of stable gas mixtures containing 0.2 to 20 ppm

benzene has been made and a GC procedure has been developed for analysis

with a precision of better than one percent. The concentrations of

these standard mixtures are currently being verified by comparison to

benzene permeation tubes which have been calibrated gravimetrical ly.

This will ultimately lead to a benzene in air Standard Reference Material

(SRM) which has its accuracy derived from two independent bases. The

procedure developed for benzene will serve as a prototype for the development of other high priority toxic organic gas standards.

Methods for preparation of accurate and stable standards of benzene

and perchloroethylene in air have been studied. These particularly

difficult gas systems have required the development of special techniques both for preparation of mixtures of predictable concentrations

and for their subsequent analysis.

The increasing concern with the potential hazards associated with

certain organic compounds in the ambient and industrial workplace

atmospheres have empahsized the need to solve the difficult problem of

standardization of the measurement of low concentrations of intermediate

molecular weight volatile organic compounds. The compounds of interest

include benzene, toluene, perchloroethylene, chloroform, carbon tetrachloride, ethylene di chloride, and tetrachloroethylene. Work completed

several years ago at NBS indicated that mixtures of these compounds in

air at high pressure in steel cylinders could not be prepared with

predictable stability. However, aluminum cylinders, which have reduced

adsorptive and absorptive properties of the inner surface compared to

steel cylinders, appeared to be capable of containing organic mixtures

with reduced losses.

Consequently, mixtures of benzene in air and perchloroethylene in

air were prepared by a micro-gravimetric technique developed at NBS and

the concentrations were determined over a period of several months. The

109
benzene mixtures which ranged in concentration from 0.2 to 10 ppm were

found to have the same relative concentration, within the uncertainty of

the analytical technique, over this period. The ususal difficulties

associated with the analysis of sub-ppm concentrations of benzene in air

samples were encountered during these determinations. The effects of

the non-linearity of response to concentration ratios, the imprecision

of integration for small peaks and the drift of the flame ionization

detector response due to slow changes in instrument and sampling conditions

were moderated by using multiple-standard calibration curves and careful

sampling techniques. The elimination of the interference caused by a cylinder contaminant (probably residual trichloroethylene) was accom- plished by the careful selection of the column parameter (i.e., length,

material, temperature), and carrier-gas flow rates.

The gravimetric method used to prepare the air mixtures of benzene

or perch! oroethylene was devised to overcome the problem of transferring

a vapor at low pressure into a cylinder without contamination by atmospheric

air. The organic liquid was introduced into a previously weighed capillary

tube which was then sealed and reweighed to determine the weight of the

organic. The capillary tube was then placed in a short length of flexible

tubing which in turn was connected to the weighed sample cylinder. The

capillary was broken inside the flexible tube and the contents were

flushed totally into the sample cylinder. The sample cylinder was then

filled with the diluent gas whose mass was determined by difference

after weighing the filled sample cylinder. Gravimetric standards with

uncertainties in their concentrations of less than ± 1 percent relative

can be thus prepared.

Alternatively standards may be generated by permeation tubes con- taining the substance of interest. However, the accuracy of mixtures

generated with permeation tubes depend to a great extent on the stability of the permeation rate. Tubes containing a number of different

organic compounds were studied over a period exceeding one year. The

results showed that tubes containing benzene required as much as one month to reach equilibrium at constant temperature. Tubes containing

other organic compounds required greater or lesser times depending on the particular organic involved. The rates after equilibrium, however,

were found to have uncertainties of less than ± 1 percent relative.

It appears that permeation tubes may serve as adequate standards

providing the conditions under which they are kept are carefully controlled

and if frequent measurements of the permeation rate are made.

110
(3) ACID PRECIPITATION QUALITY ASSURANCE SAMPLES

Participants : W. Koch, E. Garner

Background :

NBS had earlier prepared and analyzed three series of simulated

rainwater reference solutions. The 1975 series consisted of four

multicomponent solutions analyzed for metals, anions, conductivity,

pH and acidity. In 1977, three multicomponent solution types

(analyzed for all of the aforementioned) and one single component

solution types (analyzed only for pH, acidity and conductivity)

were prepared. In 1979, two multicomponent and two single com- ponent solution types were prepared and analyzed. With the increase in interest in acid rain, the single component solutions

(essentially dilute sulfuric acid) are becoming more important and

are comming under closer scrutiny. At present, there is an insufficient data base to adequately address the problems at hand, most

notably stability of these unbuffered solutions toward pH and

acidity, and and an accurate protocol for the measurement of pH in

unbuffered solutions. In addition, there is some concern that the

existing solutions are too few in number and variety and that they

do not cover the entire range expected in natural rainwater.

The basic components of the multi-year NBS research plan are:

1. Check the existing solutions for stability, especially pH

and acidity over a two-year span.

2. Evaluate glass electrodes and reference electrodes for

response time, stability, and accuracy in low conductivity

unbuffered solutions. Develop a method for accurate and

precise measurement of pH and acidity in such solutions.

3. Conduct research toward devising a stable chemical system

having the following characteristics:

0

pH 3.0 to 5.0

0 acidity 3 meq/L to 10 meq/L

0 conductivity 30 to 100 yS/cm

Project Milestones

1 . FY-1980 :

0 Research and identify the problems and present limitations in the measurement of acidity and pH in rainwater. (Completed)

0 Initiate a program to check the stability of existing

reference solutions (Simulated Precipitation Reference

Materials III) with regard to pH and acidity using

potentiometric and coulometric techniques. (Completed)

111
2 . FY-1981:

0 Continue stability check program.

0 Evaluate various types and configurations of pH

electrodes (glass and reference) in terms of response

time, stability, and accuracy in low conductivity,

unbuffered solutions.

0 Evaluate the use of spectrophotometric methods for

measuring pH in low conductivity, unbuffered solutions.

0 Initiate research toward devising a stable chemical

system having the following characteristics: pH 3.0

to 5.0; acidity 3 to 10 meq/L; conductivity 30 to 100 yS/cm.

3. FY-1982 : 0 Conclude stability check program on Simulated Precipitation

Reference Materials III.

0 Continue research in a stable chemical system for acid

rain reference material and produce a limited set of

solutions for long-term stability testing.

0 Develop protocol for pH and acidity measurements in

rainwater.

Project Progress-FY-1980

1 . Project Synopsis

A multi-year project concerned with acid rainfall was initiated.

The scope of this project is to investigate and identify the problems

and present limitations in the measurement of acidity and pH in rainwater. Based on the findings, research will be conducted to develop

stable acid conductivity measurements in low ionic strength unbuffered

solutions. This will require NBS competences in pH, potentiometry , and

conductimetry

.

Work was initiated on checking the stability of existing reference

solutions (Simulated Precipitation Reference rials I, II, and III)

prepared by NBS for EPA audit programs. There appeared to be a stability

problem with some of these solutions. In addition, a literature survey

was initiated to identify problems and limitations in the measurement of

acidity and pH in rainwater. This survey revealed serious deficiencies

in acid rain measurements and the need for an adequate measurement

protocol. A more detailed examination of the literature was undertaken.

Further investigation of stability on existing reference solutions

contained in glass ampoules confirmed the presence of instability with

some of these solutions. Further work is in progress to quantify the

instability and its source. In addition, a small set of dilute sulfuric

112
acid solutions (similar to Simulated Precipitation Reference Materials

III, seried 940000, but contained in C.P.E. bottles) was prepared. The

stability of these solutions is being monitored with respect to pH and

conductivity.

2. Related NBS Activities

During the past year, a programmable computing integrator was added

to the ion-chromatograph which greatly expands its usefulness as an analytical tool. It is hoped that similar data aquisition and data

management devices can be acquired for voltammetry, coulometry, and

potentiometry to improve measurement capabilities and to handle routine

mathematical operations.

In the coming year, in addition to an anticipated intense sampleanalysis effort, the Electroanalytical Chemistry Group will engage in

research to develop a species-selective and sensitive anion detector for

ion-chromatography based on amperometric principles. Investigations

will be conducted as to the sources of and remedy for possible systematic

errors in high-precision coulometric measurements which may adversely

affect the accuracy of the method.
(4) AIR GENERATIOR COLUMNS

Parti ci pants : W. E. May, W. J. Sonnefeld

Background :

Dilute solutions of polycyclic aromatic hydrocarbons (PAH's) in air or an inert gas matrix may be produced by adapting and modifying

existing water generator column methodology. Studies undertaken to

date seem to indicate that such gas solutions are saturated, and

thus, thermodynamic constants can be determined. For example, the

heat of vaporization of naphthalene was determined to be 16.5 ± 0.1

kcal/mole using this method. This value compares favorably with

the literature value of 15.6 kcal/mole (Zh. Fix Khim., 42, 1814

(1968)). The gas solutions produceable by air generator columns

are, by nature of being saturated at the generation temperature,

standard PAH in air solutions, and may be utilized for measurement

calibration purposes. However, the methodology required needs to

be refined and application needs to be made to other PAH calibration

compounds of higher ring size, including biologically important PAH

such as benzo[a]pyrene. Initial work on this project will focus on anthracene, since reliable data exist for this PAH in the literature

(API Monograph).

Project Progress-FY-1980

1 . Project Synopsis

Work was initiated on this exploratory project to determine the

feasibility of developing air generator columns as standards for generator columns as standards for generating accurate concentrations of

PAH components in air. The technical approach was based on the evaluation of an air generator column containing a given PAH for measurement

of its vapor pressure as a function of column temperature by use of

method, PAH effluent trapping, and HPLC analysis.

2. Project Detail

The feasibility of developing a Standard Reference Material for

organic compounds in air is being investigated. A gas-saturation technique is being used to produce a saturated vapor solution of an organic

compound at its thermodynamic equilibrium vapor pressure. The vapor is

cryogenically trapped and then analyzed by coupled-column high-performance

liquid chromatography.

The gas saturation method for the determination of vapor pressures

dates back to 1845. However, due to the lack of sufficiently sensitive

analytical techniques, this method has not been extensively used until

recently. Cliath and Spencer (Report to NAS-NRC Evaluation Panel, 141,

(1978)), in a series of experiments, utilized the method to study desorption isotherms of pesticides. Pella (Anal. Chem. , 48, 1632 (1976)),

coupled a gas-saturator to a gas dilution system to produce a calibration

system for exploring vapor detectors. May (Environ. Sci. Technol., _3> 670 (1969)), used the dynamic-coupled-column HPLC technique to determine

the vapor pressure of naphthalene. Comparison with published data

showed that a systematic error was present in this work.

114
This study has been concerned with eliminating the systematic

errors discovered earlier and extending the technique to vapor-phase

studies of the larger polynuclear aromatic hydrocarbons. The dynamiccoupled-column HPLC system has been modified to include dual 6- port

valves which allow for purging of the coll*ection assembly by an inert

gas. The techniques of column conditioning used for the water SRM

generator columns have been applied to this work in order to properly

remove any impurities from the starting material. The system is designed to permit continuous flow through all channels so as to eliminate

sorption effects. Thus, the system is dynamic in nature. The generator

columns and all connecting flow lines are constantly submerged in an isothermal bath. The vapor is concentrated on either an octadecyl

silane-packed column (C-18) or via a cold trap assembly. The initial

work has used an anthracene generator column. The concentration at 25°C

has been determined as 60.2 ng/L with a precision of 1.4 percent relative.

Studies of the dependence of the flow rate upon the vapor density

have shown that the vapor density remains constant for flow rates below

14 cm

3 /min.

Initial temperature studies (Table 18 ) have shown excellent agreement with extrapolated data obtained by other techniques.

Future work will include studies of several columns containing

varying concentrations of anthracene-coated Si02 . The effects due to

the presence of other compounds and that due to~the water vapor con- centration will also be studied. Finally, a systematic check will also

be used to determine if any systematic errors are present.

115
Table 18. Preliminary Determination of the Polycyclic

Aromatic Hydrocarbon Vapor Pressures as a Function of Temperature.

Temperature m

Temperature Vapor

Pressure (torr x IQ 6

)

15.3 288.5 2.68

2.57

2.75

20.4 293.6 4.51

4.71

4.59

25.0 298.2 6.29

6.39

6.19

30.1 303.3 11.4

11.6

11.1

34.9 308.1 20.3

19.9

19.4

As soon as the technique has been completely verified, it will be

used to obtain the vapor pressure curves at ambient temperature for a series of polycyclic aromatic compounds. These data are presently

available only by extrapolation of data obtained at higher temperatures.

Further applications will involve the use of the generator columns

for calibration of high-volume atmospheric sampling systems.

116
(5) OZONE PHOTOMETERS

Participants : A. Bass

Background :

The ozone layer in the stratosphere protects all forms of life at

the surface of the earth from excessive exposure to solar ultraviolet radiation. There is great concern that the emission of

substances such as nitrgoen oxides and halocarbons into the atmosphere may modify the ozone layer and cause possible harm to life

on earth. Measurement of ozone concentrations in the upper atmosphere of the earth is essential in order to detect changes that

may be caused by man's activities. Total ozone column density and

vertical profiles are determined mainly by means of ultraviolet

(UV) absorption spectrophotometry. A specially designed NBS

research spectrometer had been designed for accurate ozone mea- surements. EPA, under its authority in the Clean Air Act, is

required to assure accurate measurements of atmospheric ozone as a pollutant, as well to assess stratospheric ozone protection. EPA

has requested that NBS design a standard ozone photometer based on NBS experience with the research instrument that, upon replication

can be placed in EPA Regions for national ozone measurement quality

assurance.

Project Milestones and Estimated Completion Dates

1. FY-1980 :

0 Develop instrument performance specifications relative

to accuracy and precision. (Completed) 5/80

0 Initiate prototype instrument design and component

testing. (Initiated) 6/80

2. FY-1981 :

0 Design of prototype instrument and test components

of the prototype in combination with one another. 2/81

0 Complete preliminary prototype instrument design. 2/81

0 Fabricate prototype photometer. 9/81

3. FY-1982 :

0 Performance testing and verification of prototype

photometer relative to design specifications

(EMSL/RTP and NBS). 11/81

0 Complete final design of photometer and develop

revised cost estimate, if any. 11/81

0 Fabricate, test, and deliver three photmeters to EPA. 6/82

117

CROSS-SECT

I

ON

(SQ.CM.

X

10

EXP20

)

.00

2.00

3.00

4.00

S.00

6.00

7.00

8.00

9.0C

o

(nm)

Figure 14. Absorption spectrum of ozone at 298 K and 244 K. Spectral slit width 0.02 nm; wavelength scanned

in steps of 0.05 nm.

119
(6) ENERGY-RELATED GAS STANDARDS DEVELOPMENT

Participants : E. Hughes, W. Dorko, G. Sleater

Background

Due to the Nation's need for increased energy production, the

abundance of major natural resources that may be used for this

purpose in the Western U.S., and the anticipated marked Increase

in power plant development in the West, EPA established the

Western Air Quality Monitoring Project under its Western Energy/

Environment Monitoring Study (WEEMS) to provide monitoring data

to assess the environmental impact produced by present/projected

energy-related development activities. In addition, the con- version of power plants to coal -firing is on the increase in

the U.S. In order to provide data quality assurance in quantitating energy- related air pollutant emissions associated with

conventional and fossil fuel conversion technologies, EPA

recognized the need for the development and provision of gaseous

SRM's by NBS and the need to establish a mechanism to insure

traceability of commercially-prepared gas standards to NBS

SRM's for quality assurance in national activities for the

monitoring of pollutant gas concentrations in air.

As in the past the major output of the NBS Gas Metrology Group

has been in the analysis and certification of gaseous Standard

Reference Materials (SRM's). Over 3400 individual samples of

SRM's have been analyzed during the past year. In addition,

85 gaseous SRM's sold by the Office of Standard Reference Materials

have been returned by the users for reanalysis as part of a continuing study of the stability of gas standards. It is

anticipated that seventeen new SRM's will be issued by the end

of FY 1981. These new SRM's include low concentrations of

sulfur dioxide in air, nitric oxide in nitrogen, oxygen in

nitrogen, and propane in nitrogen, all at concentrations extending

the range of existing SRM's.

Project Progress - FY-198Q

1 . Development of SRM's for Stationary Sources Associated with

Energy Production

(a) NOq in Air Gas Blend SRM's

The four levels of gas mixtures, 250, 500, 1000 and 2500 ppm NO

2

in air, were received and each batch was evaluated to determine homogeneity.

The batches at 250 and 2500 ppm were produced by one supplier and the

batches at 500 and 1000 ppm were provided by another supplier.

120
The results of the first set of intercomparisons are given as follows:

Intercomparisons of N0

2

in Air Cylinders for Certification

Nominal Range of s.d. of the

Concentration Concentration Concentration

(ppm) (ppm) (ppm)

250 17 5

500 18 5

1000 12 3

2500 45 12

The lesser standard deviation relative to the range of values

reflects the fact that most samples had concentrations close to the

average but that in each lot there were several outliers. A second

analysis of all samples is essential to determine whether the outliers

represent unstable samples or samples whose concentration fell at a lesser value at the time of preparation.

The results were encouraging, however, since a larger spread

in the value was expected. A second analysis of the four sets was conducted in April 1980. The four SRM's are planned for completion by

March 1981

.

( b ) SOq in No SRM's

Orders were prepared for the purchase of 50 and 90 ppm S0

2 in

N

2

* The laboratory standards necessary for the certification of the

50 and 90 ppm S0

2

SRM's were prepared and evaluated. Both a chemical

method (hydrogen peroxide method) and gas chromatography will be used

in the certification. The SRM's are planned for completion by December

1980.

(c) NO in Nq SRM's

SRM's have been issued for 1500 and 3000 ppm NO in N

2

.

(d) 0

2

in N

3

SRM's

Two new SRM's (SRM #2657 and #2658) consisting of two and ten

mole percent 0

2

in N

2 were completed.

(e) COq in Air SRM's

Development of standards for the accurate measurement of carbon

dioxide have progressed to where excellent agreement with accepted

international standards have been achieved. As a result, a large

number of samples are being prepared commercially which will be used

to study the feasibility of large scale production of highly accurate

and stable C0

2 gas standards. If production on a large scale is

feasible then these standards, as SRM's, will be integrated into

the existing measurement network for atmospheric carbon dioxide.

121
2. Automation of Gas Analysis

A second Computer-Operated Gas Analysis System (COGAS- II) has been

constructed, and is in use for certification analysis of SRM's. A third

system ( COGAS- III) has been constructed for the automation of permeation

tube calibrations. Preliminary results indicate that the system will

operate as intended.

Under a separate program with the Motor Vehicle Manufactures Association, ten new carbon monoxide in nitrogen mixtures were developed

involving measurements which demonstrated the usefulness of high-pressure injection from large sample loops into a gas chromatograph to

increase detector response for carbon monoxide mixtures at concentrations

of less than 100 ppm. The technique allowed the intercomparison of

samples with standards with a precision of ± 0.2 percent. Certification

of these SRM's involved the first test of the software used to control

the combined gas chromatography NBS-developed computer operated-gas

analysis system (COGAS). ! COGAS had previously been used only with

continuous flow gas analyzers.

3. Development of an NBS/EPA Traceability Procedure for Gas Standards

Preliminary reviews of a procedure for establishing traceability of

commercially prepared mixtures to certain gaseous SRM's were completed.

A meeting with representatives of the gas industry was held to discuss

the practicability of the NBS developed procedure relative to the stateof-the-art both of the preparatory processes and the analytical procedures .

The demand for gas standards is increasing at an accelerated rate.

Improvement in instrumentation during the last two decades and mandated

requirements for accuracy in gas measurements related to environmental

concern have both contributed to the demand. Limitations imposed on the

gaseous SRM program resulted in severe shortages of standards which on occasion has caused concern among regulatory agencies, users and producers. Since it is not realistic, either philosophically or physically,

to consider expanding the gaseous SRM program beyond its present bounds,

it has become essential to establish some alternative supply of accurate

standards. As a result of this need a protocol has been developed which

in essence transfers the responsibility for producing large numbers of

accurate standards (Certified Reference Materials) to the specialty gas

industry. The protocol makes provision for monitoring by the regulatory

agencies and at the same time NBS retains the responsibility for assuring

traceability of the Certified Reference Materials (CRM's) to NBS gaseous

SRM's.

According to the protocol, the specialty gas producer will prepare

CRM's at concentrations equal to or very close to the concentration of

existing SRM's. These will be prepared in large homogeneous batches.

The producer will analyze each CRM from the batch by comparison to an

SRM. The regulatory agency will select samples from each batch for

analysis. The analysis by the regulatory agency will be performed using

122
SRM's as cal ibrants . Both the producer and the regulatory agency will

furnish NBS with complete information concerning the production and

analysis of the CRM's including the data for both calibration of the

instruments used and the analysis of the CRM's. NBS will then statistically

compare the results reported by the producer with those found by analysis

by the regulatory agency. In addition, NBS will examine all the results

reported by the producer to ascertain the homogeneity of the batch.

From these data it will be possible to verify the total uncertainty of

the concentration claimed by the producer. At this point the concerned

parties will be notified that the particular batch of CRM's has been

prepared in accordance with the protocol and that the stated concentration is correct within the defined limits of uncertainty.

The protocol in its present form has been extensively modified in

response to comments from the gas industry, users of SRM's and the

principal regulatory agency, the Environmental Protection Agency. It is

not a "cook book" by which CRM's can be prepared. Rather, it recognizes

the experience and expertise of the specialty gas industry while at the same time it recognizes the reservations which the user may have re- garding the industry and which the industry may have regarding the

regulatory agency. It is expected that the role of NBS as an independent

overseer will inspire confidence not only in the quality of the CRM's

but in the integrity of the entire procedure.

The availability of CRM's should moderate the demand for the

corresponding SRM's, so that the latter would be used largely as primary

standards, which was the purpose for which they were originally produced. A document has been prepared for publication under the Interagency Energy-Environment Program, entitled "A Procedure for Establishing

Traceability of Gas Mixtures to Certain National Bureau of Standards

Standard Reference Materials."

123
(7) ENERGY-RELATED PARTICULATE STANDARDS DEVELOPMENT

Participants : P.A. Pella, W. Koch, E.C. Kuehner, J. Sieber,

C. C. Gravatt

Background :

In concert with the needs to develop energy-related gas standards

(q.v.), development of particulate standards is needed to provide

data quality assurance in the monitoring of particulate emissions.

This need is magnified by the anticipated increase in conventional

fossil fuel combustion and the anticipated increased activities in

converted fossil fules and oil shale to address the Nation's increasing

energy needs. EPA has placed an empahsis on both total and fine

particulate emissions monitoring.

The activities in the EPA/NBS E/E program for FY 1980 for

particulate standards development have covered: (a) the evaluation

of standards for x-ray fluorescence analysis; (b) development of Pb

(in addition to sulfate and nitrate) on glass fiber filter standards;

and (c) work on the air particulate collection in the Washington,

DC area.

Project Progress-FY-1980

1 . Development of Thin Glass Films As Potential Standards

for X-ray Spectrometric CalibratiolT

X-ray fluorescence spectrometry has proven to be a versatile and

rapid method for multielement analysis in many analytical applications.

Of particular interest are substances which can be analyzed in the form

of a deposit on a filter, mesh or membrane, or as a thin pressed pellet.

Collected airborne particulate matter, particulates in waste water and

geochemical samples are just a few examples of this type. In some respects such "thin samples" are ideal for x-ray fluorescence analysis

because the detection limits are suitably low and interelement effects

such as x-ray absorption and/or enhancement are negligible. The absence

of any sizable interelement effects makes possible a linear instrument

response to element mass per unit area. Spectrometer calibration for

analysis of such samples is usually performed with thin samples containing

known concentrations of the analyte(s) of interest. Some problems

associated with the "thin specimen model" are x-ray self-absorption in

particles (notably for the light elements such as A1 , Si, P, and S)

commonly referred to as particle-size effects, and self-absorption in

the substrate. Both of these effects require the application of correction

factors. Therefore, the basic premise is that accurate multielement

analysis of thin samples can be performed based on the thin specimen

model, together with empirical or theoretical correction factors.

124
There are several important criteria which need to be met if thin

samples are to be acceptable for calibration purposes. First, the

uniformity of the sample as well as its homogeneity must be within an acceptable well-defined tolerance limit. If the sample contains particulate matter, both the size and distribution should be characterized.

Secondly, the mass loading of the sample must be known to an acceptable

degree of accuracy. And finally, the sample should possess sufficient

durability and integrity.

The goal of a joint program between NBS and the U.S. Environmental

Protection Agency (EPA) was to perform the research and development

required to produce thin standard samples especially useful for calibration of x-ray fluorescence analysis of collected airborne particulate

matter. For this purpose we have investigated several candidate methods

for preparing such samples.

One method which shows great promise is the deposition of thin

films of glass containing known concentrations of several elements of

interest on polycarbonate substrates by a technique known as focused

ion-beam sputtering. Ion-sputtering essentially involves the transfer

of atoms and/or molecules from a target to a substrate by the action of

an ion beam (usually argon) incident upon the target. The ion beam is

accelerated at high potential (700-1100 volts) with a flux of about 0.5

mA/cm2 toward the target at a 45° angle. Since the substrate is not in

the plasma environment, substrate damage does not occur. This is a distinct advantage of this particular sputtering technique. Other

advantages to be gained are: (1) production of thin films from synthetic

materials such as glasses of known elemental composition which can be

varied as desired; (2) high adherence of the glass to the substrate

which obviates the need for overcoating to maintain sample integrity;

and (3) easy control of the glass mass loading on the substrate by

variation of the sputtering time.

Several studies were performed with glass targets fabricated at NBS

which allowed up to eight 47 mm substrates to be coated at one time.

Instrumental parameters such as ion accleration voltage and ion current

were systematically varied to determine their effect on film composition.

It was found that rather severe changes in these parameters often do not

affect the film composition by more than ± 15 percent. Glass films

sputtered from targets containing phosphorous and sulfur were also

prepared to demonstrate the feasibility of preparing films containing

elements of low atomic number.

In Table 19 are summarized the elemental compositions of three sets

of films at mass loadings ranging from 167 to 185 yg/cm2 which were

prepared at various times. These data demonstrate that the compositional reproducibility of thin films from set to set is satisfactory for

the purposes of preparing standard films.

125
Multi -element thin standards suitable for calibration purposes can be fabricated by the focused ion-beam sputtering technique. In order to

include all the elements of interest in any particular film, several

glass targets would need to be fabricated. It is believed that these

films would be useful to monitoring agencies such as EPA for assessing

environmental impact of airborne particulate matter. Work is now in

progress to prepare several sets of films which will be certified by the

Office of Standard Reference Materials as NBS Standard Reference Materials.

2. Particulates on Glass Fiber Filters: Certification of

SRM's for Pb, Sulfate, and Nitrate on Filter Media

Final certification of SRM 2673, Sulfate and Nitrate on Filter

Media, and SRM 2674, Lead on Filter Media, has been completed. These

materials are intended for use in the evaluation of apparatus and

methods used in the determination of lead, sulfate, or nitrate in

atmospheric particulates collected on filters.

Certification measurements for the anions were accomplished by ion

chromatography. Lead for SRM 2674 was determined by both voltammetry

and atomic absorption spectrometry (AAS). Statistical analysis of the

data indicated no significant effects of biases in the AAS due to

undissolved solids from the glass filter matrix.

Copies of the certificates of analysis are included for information.

3. Urban Air Particulate, Washington, D. C. Sample

In August 1979, the collection of the Washington, DC, urban particulate sample was terminated. The bags were vacuumed out using the same system as that described for the St. Louis material, and approximately

45 pounds of unsieved material was obtained. Several sieving strategies

were evaluated in order to develop one that was effective in removing

bag fibers, but did not excessively reduce the non-bag-fiber fraction of

the sample. It appears that 30-35 lb. of sieved material will be available

for final analysis. Preliminary inorganic, organic, and particle size

analysis has been performed on the Washington material. The analysis

indicated that the Washington material can be used either as a replacement

for the St. Louis material or as an organic certified sample.

126
Table

19.

Composition

of

Glass

Films

at

Higher

Mass

Loadings

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127

Standard

deviation

of

the

mean

value

i.e.,

(S//n)

where S

is

the

standard

deviation

ofa

single

measurement.
U.S. Department of Commerce

Juanita % Kreps

^eeseiary,7

National SureawoTStandarda Emeat i^mMpr, pirector

JCaitimal Jlur&tu

(Heriifttate of

of jltatttiartfe

Analysis

Standard Reference Material 2673

Sulfate and Nitrate on Filter Media

This Standard Reference Material is intended for use in the evaluation of apparatus and methods used in the determination of atmospheric particulate sulfate and nitrate which have been collected on filters. It consists or a series of filter strips upon which sulfate and nitrate have been deposited in an essentially central location. The

values certified correspond to the quantities of the substances leached from the filter strip without destruction of

the filter matrix.

Sample

Number

1 Sulfate content ng/ filter Nitrate content ng/ filter

Average value Tolerance limits Average value Tolerance limits

I 503 493 - 513 100 98 - 102

II 2002 / 1955 - 2049 1002 978 - 1026

III 6939 6635 - 7243 2513 2404 - 2622

Blank 2 0-6* 2 0-3*

* Range of measured values The average value is the mean based on the analysis of 24 or 28 filters randomly selected from the lot. The

tolerance limits are determined so that at the 95% confidence level they will contain the central 95% of the population of filter values. Details of the preparation, analysis, and statistical treatment of the data are given on

the reverse side of the certificate.

This Standard Reference Material was prepared by B. I. Diamondstone. The analytical measurements were made by W. F. Koch. Statistical analysis of the data was provided by J. Orban. The overall direction and

coordination of the preparation and analytical measurements leading to certification were performed in the Center for Analytical Chemistry under the chairmanship of J. K. Taylor.

The technical and support aspects involved in the preparation, certification, and issuance of this SRM were

coordinated through the Office of Standard Reference Materials by W. P. Reed.

Washington, D.C. 20234

June 25, 1979

(over)

128

George A. Uriano, Chief

Office of Standard Reference Materials
Preparation

This SRM consists of strips cut from glass fiber filters, such as are commonly used for measurements of

atmospheric particulates, using high volume samplers. Solutions containing known amounts of potassium

sulfate and potassium nitrate were prepared, gravimetrically, and multiple aliquots of 25 fj.L were placed on the

filter strips. Four aliquots were so transferred to each filter in the case of samples I and II, and five in the case of

Sample III. The pipets were calibrated by weighing similar aliquots transferred into weighing bottles. The filters were prepared in a clean room and allowed to air-dry before packaging in glassinc envelopes. The

filters were prepared in groups of 100 and the proper number of aliquots were dispensed into weighing bottles at the beginning and end of each sequence, to monitor the performance of the pipet.

Analytical Measurements

Twenty four samples were randomly selected from the production lot (28 in the case of sample III) for chemical

measurement of their extractable sulfate and nitrate. Each filter strip was extracted with a standard eluent (see

below) for 15 minutes in a 55 °C ultrasonic bath. The extracts were analyzed for sulfate and nitrate by ion

chromatography. The eluent was a solution of 0.003 MNaHCC>3 and 0.001 8 MNa2CC>3 . A 100 /xL sample loop was used. Peak heights were compared with those obtained from accurately prepared standard solutions. Three

standards were prepared for each concentration level so as to bracket the extracts. The randomly selected filters were also analyzed in random order. No significant systematic errors were

observed related to the order of preparation. Average values and the overall standard deviation, so, of

individual measurements were calculated. This standard deviation includes measurement error and filter content error. The standard deviation, Sf, due to filter content variability was computed from a sample of 12 or 14 weighed

quantities delivered by the pipets during the preparation of the filters. The resulting tolerance interval for the

sulfate /nitrate contents is of the form

X ± k sf .

It is this tolerance interval that should be of greater interest to the participating laboratory since it gives practical

bounds for the likely values of the sulfate or nitrate contents that might be found in a given filter. The following table lists the values of so and Sf for each set of filters. The measurement standard deviation, sm, for NBS can be computed using the relation sq

2 = sm2 + Sf2

Set Average (jug) So Sf

so4 502.6 8.89 3.14

no3 100.3 2.56 .63 so4 2001.7 29.30 14.88 N03 1001.7 15.92 7.44

so4 6939.0 109.35 100.75

N03 2513.0 43.70 36.30

The average values calculated from the composition of the solutions and the quantitites delivered by the pipets are in general agreement with the analytical values. However, the values certified are those obtained by analysis.

Recommended Usage

The material is not homogeneously distributed on the filter; hence the sample must be used in its entirety for

analysis. It is recommended that the filter be extracted at 55 °C in an ultrasonic bath, with water or other

nonreactive solvents. The filter base should not be digested to put it into solution.

129
U S. Department of Commerce

Juanita M* Kreps

Secretary

! jt \ National 0uremrof Standards

Ernest Ambler, Director

Rational ^Bureau of Standards

3 ertificate of JnttaJ'gsts

Standard Reference Material 2674

Lead on Filter Media

This Standard Reference Material is intended for use in the calibration of apparatus and the evaluation of

methods used in the determination of atmospheric particulate lead which has been collected on filters. It consists

of a series of filter strips upon which lead has been deposited in an essentially central location. The values

certified correspond to the quantities of the substance leached from the filter strip without destruction of the

filter matrix.

Sample No.

Lead Content, /zg/ filter

Average Value Tolerance Limits

1 100 97 - 103

II 303 294 - 312

III S505 1477 - 1533

Blank 1.4 0.7- 2.1*

Range of measured values The average value is the mean based on the analysis of 26 or 28 filters randomly selected from the lot. The

tolerance limits are determined so that at the 95% confidence level they will contain the central 95% of the

population of filter values. Details of the preparation, analysis, and statistical treatment of the data are given on

the reverse side of this certificate.

This Standard Reference Material was prepared by B. I. Diamondstone. The analytical measurements were made by E. J. Maienthal and M. S. Epstein of the Inorganic Analytical Research Division. Statistical analysis of

the data was provided by J. Orban of the Statistical Engineering Division.

The overall direction and coordination of the preparation and analytical measurements leading to certification were performed in the Center for Analytical Chemistry under the charimanship of J. K. Taylor.

The technical and support aspects involved in the preparation, certification, and issuance of this SRM were

coordinated through the Office of Standard Reference Materials by T. E. Gills. Washington, D.C. 20234 George A. Uriano, Chief

December 18, 1979 Office of Standard Reference Materials

(over)

130
Preparation

This SRM consists of strips cut from glass fiber filters of the type normally used in high volume samplers for the measurement of atmospheric particulates. Solutions containing known amounts of lead nitrate were prepared

gravimetrically, and aliquots of 25 juL were placed on the filter strips using micropipets. Four aliquots were

transferred to each filter in the case of samples I and II and five in the case of sample III. The pipets were

calibrated by weighing similar aliquots transferred into weighing bottles. The filters were prepared in a clean room and allowed to air-dry before packaging into glassine envelopes. The

filters were prepared in groups of 1 00 and the proper number of aliquots were dispensed into weighing bottles at the beginning and end of each sequence, to monitor the performance of the pipet.

Analytical Measurements

Twenty-eight filters were randomly selected from the production lot (26 in the case of Sample I) for chemical

measurement of extractable lead. Selected filters were extracted with dilute nitric acid, using ultrasonic

vibration to assist in the extraction. After the nitric acid extraction, the filters were thoroughly rinsed with

distilled water to ensure complete extraction. The extracts were quantitatively diluted and analyzed by linear sweep voltammetry which had been calibrated with solution standards prepared from high purity lead. The selected filters were analyzed in random order. No significant systematic errors were observed related to order of preparation. Average values were calculated together with the overall standard deviation, s0 , of

individual measurements. This standard deviation includes measurement error and filter content error. The

resulting confidence interval for the mean is of the form

X ± t So//~n",

where s0 is based on n - 1 =27 degrees of freedom.

A selected number of filters were also analyzed by atomic absorption. The results obtained were well within t he

tolerance limits given and were consistent with the certified values. The standard deviation, Sf, due to filter content variability was computed from a sample of 12 or 14 weighed

quantities delivered by the pipets during the preparation of the filters. The resulting tolerance interval for the lead content is of the form

X ± k sf.

It is the tolerance interval that should be of greater interest to the participating laboratory since it gives practical

bounds for the likely values of the lead content that might be found in a given filter. The following table lists the values of s0 and Sf for each set of filters. The measurement standard deviation, s m , for NBS can be computed using the relation s0

2 = sm2 + Sf2

Set Average (/ug) So Sf

I 99.7 1.59 0.89

II 302.9 5.37 3.00

III 1505.2 12.73 9.24

The average values calculated from the composition of the solutions and the quantities delivered by the pipets are in general agreement with the analytical values. However, the values certified are those obtained by the

analysis.

Recommended Usage

The material is not homogeneously distributed on the filter, hence the sample must be used in its entirety for

analysis. It is recommended that the filter be extracted at 45-50°C in an ultrasonic bath, with dilute nitric acid (2

mL HNO3 + 15 mL H2 O). After extraction the filters should be thoroughly rinsed with distilled water. The filter base should not be dissolved.

131
AIR MEASUREMENTS - METHODS DEVELOPMENT

a. Overview

New and improved methods of analysis are necessary if advancements

are to be made in measurement technology for the characterization and

assessment of air pollutants. Existing methods do not always adequately

address characterization and quantification of pollutants derived from

diverse sources or adequately measure personal exposure of toxic materials.

The matrix of pollutants of national interest has become substantially

more complex, due to growing environmental concerns in such areas as toxic substances and developing energy technologies (coal conversion,

shale oil). Hence, method development activities at MBS must focus

not only on the development or improvement of methodology for certification

of needed national standards (research materials and SRM's), but must

attend the present and intermediate range needs for advanced measurement

methods and instrumentation that insure a viable continuity in the development of measurement capabilities for air pollution measurements. In

addition to the qualitative and quantitative aspects of new or improved

measurement techniques, measurement uncertainties must be well characterized

in order to insure the reliability of conclusions based upon the experimental

data derived from field measurements.

Objectives

To develop new or improved methodologies and advanced instrumentation

or devices that provide or enhance data quality assurance in national

air quality evaluations related to the characterization and monitoring

of air pollutants (e.g., from industrial and energy-producing sectors,

automobile and jet-airplane emissions). The developed methodologies

and instrumentation will serve to assist the establishment of national

criteria in air pollution abatement and air quality improvement, and

will provide relevant technology for reference methods, reliable

field measurement calibrations, and the development of RM's and SRM's

as national standards.

Interactions

This Task strongly interacts with various NBS centers (e.g..

Center for Analytical Chemistry, Center for Thermodynamics and Molecular

Science, Center for Radiation Research, Center for Applied Mathematics)

and NBS Offices (OSRM, OSRD). Initiation, performance, and modifications

to the activities of the program involve direct interactions between

the involved technical and managerial staff of NBS and relevant staff

complements within the U.S. Environmental Protection Agency, or with

other government agencies under Interagency Agreements or Other Agency

contracts. Strong interactions also exist with industry. State and

local government agencies, research laboratories, and universities.

Related MBS activities in the improvement or development of methods,

devices, or instruments having application to the measurement of air

pollutants are closely followed.

132
Task Justification

Development of improved methodologies and technologies for data

quality assurance is essential for valid evaluations of air quality

in areas of concerns for the protection of public health and the

national ecology. Attainment of these national goals is hence directly tied to the generation of reliable environmental measurements.

The activities of this Task are required, provided under, or have been

recommended by the Clean Air Act and its 1977 amendments, the Standing

Air Monitoring Working Group, the Council on Enviornmental Quality,

the Interagency Task Group on Environmental Data and Monitoring, the

Toxic Substances Control Act, and the NBS Organic Act. This Task is designed to address national priority needs for measurement methods

for air data quality assurance.

b. List of Task Projects

Project Title Source of Funding*

Personal Monitors P/T - EPA

UV Spectroradiometry P/T - EPA

Gases E/E - EPA

Particulates E/E - EPA

Environmental Assessment BEP**

*P/T : Pass Through - E/E: Energy/Environment

**Bureau of Engraving and Printing

Dept, of the Treasury

133
AIR METHODS - PROJECT DESCRIPTIONS

(1) PERSONAL EXPOSURE MONITORS

Participants : Jimmie Hodgeson, Barry Cadoff, David Bright,

Robert Fletcher, Alex Fatiadi

Introduction

Regulatory decisions on air pollution control which involve direct

and indirect costs of billions of dollars, are often made without

adequate knowledge of the health impacts of air pollution. The

weakest link in health effects studies is our knowledge of individual exposures. The importance of population exposure estimates

in air pollution health effects studies makes it imperative that

future studies include exposure estimates more representative of

what people breathe. Studies of air pollution health effects have

usually relied on one or several fixed monitoring stations to

provide data for an estimate of the exposure received by an entire

neighborhood. Epidemiologists have begun to call for something

better. Several recent meetings of specialists in the field of

air pollution health effects have led to recommendations urging

the prompt development of small, portable individual air pollution

monitors.

The overall goal of the NBS program will be to develop principles,

concepts, and actual devices for determining personal exposure

to critical air pollutants. Both passive and active monitors will

be developed to provide long-term integrated exposures and short

term events. This narrative addresses the first year of the

program, and the pollutants ERA has identified as having the highest

priority - fine particulates, nitrogen dioxide, toxic organics,

and ozone.

1 . Nitrogen Dioxide

Our first approach will be to investigate passive samplers for N0

2

- Edward Palmes of New York University Medical Center presented a paper at a recent symposium in which he demonstrated indoor measure- ments of ambient levels of N0

2

with a passive sampler. He used a simple diffusion tube, 7 cm in length and 1 cm in diameter. Forty

by 40 mesh stainless steel screens coated with triethanolamine (TEA) are placed in the bottom of the tubes. TEA is a standard reagent for

collection of N0

2 as nitrite in solution. After exposure the nitrite

is extracted and analyzed colorimetrically using standard GriessSaltzman reagent. Palmes used this approach to obtain indoor exposure

data and measured average values ranging from 50 to 200 ppb. He

has not determined sensitivity, accuracy and specificity, nor has

he compared his results with continuous measurement of N0

2

-

134
We propose as the first step, an evaluation of Palmes procedure for

the parameters mentioned above using an exposure chamber which is mon- itored with a chemiluminescence N0

x analyzer. In addition, we propose

to compare the diffusion tube witha larger area passive sampler con- sisting of a permeable membrane backed by the collecting substrate. TEA

has been shown to have a poor collection efficiency for N0

2

in solution

(ca. 50%). Investigators at EPA-RTP have shown that the addition of o- methoxy-phenol (guaiacol) increases the collection efficiency and this

will be investigated. Finally, we propose to evaluate ion chromatography

as the method for analysis of nitrite or nitrate (after oxidation in

solution)

.

EPA has expressed an interest in continuous or semi-continuous

personal monitors to obtain records of maximum hourly exposures. During

the first year we propose to provide a research plan for the development

of such a device. The most promising approach at present appears to be

a voltammetric sensor which is similar in principle to the commerically

available Ecolyzer personal monitor for CO. In the case of N0

2

, the

major problem to be overcome with this type of sensor will be interferences.

Several cormion air pollutants are active at the redox potentials required

for NCL. Thus we plan to research the feasibility of miniaturizing

other types of continuous monitors for N0

2

.

Some work has already been carried out regarding the development of

an analytical procedure for a passive personal monitor for CL. Unlike

N0

2

, an acceptable analytical work-up does not exist for collected 0^.

A preliminary evaluation has been made of a promising fluorometric

technique. Collected CL reacts with non-fluorescent 9, 10-di hydroacridine

or 9,10-dihyroanthracene to form intensely fluorescent acridine or anthraquinone. The intensity of the fluorescene produced is a linear

function for very low concentrations of 0^. The inherent sensitivity of

this fluoremetric approach should provide a passive technique with short

time resolution. Any further work on the ozone techniques will be

Deferred, with emphasis placed on N0

2

.

2. Fine Particulates

Very little work has been done on personal exposure devices for

fine particulates at ambient levels. We propose a dual and simultaneous

approach. In one approach, research will be devoted to development of

an active device consisting of a mini nature filter, with a coarse and

fine particle separator coupled to a miniature pump. The objective here

will be to develop a system which will provide a 24-hour mass average,

and provide a sample for chemical analysis for trace elements, sulfate,

nitrate, etc. by techniques such as x-ray fluorescence and ion chromatography. The second approach will be to investigate the feasibility

of developing a piezoelectric personal mass monitor. This latter approach

has the potential of providing short term exposures to fine particles.

135
The design of the filter sampling device will be of first priority.

Current options include a simple filter with a head for coarse particle

cut-off, a 90-deqree type virtual impactor with a dead space (or slow

moving air space) for collecting coarse particles, a cyclonic head and a tandem (series) filter arrangement for coarse and fine particles.

The major problem anticipated is in the mass determination. The

most advanced miniature pumps are limited to 2 li ter/mi n and the total

volume sampled in 24-hours is likely to be in the order of 2 cubic

meters or less. For a 24-hour mean loading of 25 yg/m 3 (which would be

typical for ambient levels), only roughly 50 yg would be collected. A

reasonable gravimetric precision attainable with a microbalance is

20-30 yg for a 37-47 mm diameter mi Hi pore or nucleopore (ungreased)

filter. A 300 yg loading would be required to obtain a precision in the

order of ± 10%. Longer sampling times would increase the loading, and

trade-offs may be required between sampling time and precision.

One proposed resolution to this problem is the use of a small

sampling area. If the loading normally deposited on a 37 mm diameter

filter can be deposited on a much smaller area, such as 1 cm

2

, the

loading (in terms of mg/cm2

) could be increased by factor of greater

than 10. This may be done either with a small filter or by the use of

particle collimation. The application of beta attenuation (beta gauge

developed by Lawrence Berkeley) for mass measurement depends on the

density of the loading, and this approach appears promising for the

small filter area. A beta gauge precison of less than 5 yg is predicted

based on the precision attainable with the larger filters. A 1 cm

2 area filter would also be compatible with x-ray fluorescence, for which the

sensitivity also depends on the density of the loading. Lawrence

Berkeley has also developed a promising technique for small masses on filters based on correlations of mass with optical attenuation of

visible light.

The major research problem anticipated with the piezoelectric mass sensor is the collection efficiency for very fine particles. In any

design conceivable now, there must be some air flow past the quartz

crystal, which does not act as an absolute filter. Commerical piezoelectric

mass monitors are available, and use electrostatic precipitators to

obtain high collection efficiencies for small particles. However, it

may not be feasible or practical to design a personal typei.collector

which uses a precipitator charge up to several kilovolts.

We propose to investigate the feasibility of two approaches. One

approach would be to impact the particles through a high velocity nozzle

onto a crystal coated with a sticky substrate. The objective would be to

obtain a collection efficiency which can be reasonable well-defined. A

second possible approach is to employ thermal precipitation techniques.

A thermal precipi-tator would have the following advantages: much lower

requirements than the electrostate precipitator, slow flow-rate requirements,

and high collection efficiency for fine particles.

136
3. Toxic Organics

Little work has been done to this date on detailed evaluation of

personal exposure devices for organics at ambient levels. There is also

considerable uncertainty on priorities for specific organics or classes

of organics. For these reasons, work during FY-79 will be limited to

preparation of a survey to determine the nature of the problems, the

most promising analytical approaches, and the pollutants which should be

of highest priority. This survey will provide a report that will serve

as the basis for an FY-80 work plan for evaluation of personal exposure

monitors for toxic organics. Work in this area will then commence in

FY-80, based on the established milestones having EPA and NBS concurrence.

Project Milestones and Estimated Completion Dates

1 . Nitrogen Dioxide

0 Completion of sample manifold and static test chamber

for evaluating N0

2 devices. (Completed) 5/79

0 Evaluation of the Palmes diffusion tube passive device

for N0

2

- (Completed) 7/79

0 Preliminary investigation of membrane-backed diffusion

devices as passive sensors for N0

2

- (Completed) 8/79

0 Comparison of the standard chemical method for collected

N0

2

with ion chromatography. (Completed) 9/79

0 Complete evaluation of filter ( Mi 1 1 i pore ) diffusion

barrier samplers for N0? (except for wind tunnel tests).

(Completed) 6/80

0 Complete wind tunnel evaluation of Palmes diffusion tube

sampler, and draft reports and publications on evaluation

of Palmes diffusion tube sampler and filter diffusion

barrier samplers. 1/81

137
2. Particulates

o Complete literature review of possible sampling heads

and collection techniques, and laboratory visits.

(Completed) 6/79

0 Design wind tunnel for personal sampler investigations.

(Completed) 6/79

0 Select and evaluate candidate sampling approaches.

(Completed) 9/79

0

Install and initiate calibration of test system

(particle generators, wind tunnel, sizing instrumentation).

(Completed) 10/79

0 Evaluate and calibrate wind tunnel (system performance;

velocity stability and profile; turbulence) without

aerosol injection. (Completed) 4/80

0 Complete wind tunnel and test system (particle generator,

sizing instrumentation). (Completed) 2/80

0 Evaluate commercially available pumps. (Completed) 7/80

0 Design, construct and make preliminary tests of

prototype filter head. 1/81

3. Toxic Organics

0

Report on FY-79 survey and FY-80 work plan. (Completed) 9/79

0

Set up generation system and sampler exposure chamber

for high concentration range (10-1000 ppb) for toxic

organics. (Completed) 5/80

0 Obtain commercial samplers for evaluation and establish

a priority for evaluation of toxic organics.

(Completed) 5/80

0 Develop optimum GC analytical procedure(s) and determine

linearity, precision, and minimum detection limits (MDL

)

on liquid standards (benzene). (Completed) 7/80

0 Initiate project to determine thermal desorption characteristics (e.g., desorption temperature, background,

desorption efficiency) for alternate sorbents, such as Tenax-GC, Porapaks, Ambersorbs. 9/80

138
0 Establish definitive protocol for sampler evaluation

(sample generation, exposure, extraction, calibration,

and analysis). 9/80

0 Define problems and develop detailed plan for evaluation

of samplers over low concentration range (0.01-10 ppb). 10/80

Project Progress-FY-1980

(a) Project Synopsis:

1. Nitrogen Dioxide

In work on N0

2 personal exposure monitors (samplers), a detailed

progress report on a static evaluation of the Palmes diffusion tube

sampler and FY-1979 work on N0~ monitor evaluations was completed and

submitted to the EPA Project Officers for this project. Initial work in

FY-1980 concentrated on the design and evaluation of membrane diffusion

barrier samplers. The Palmes device was shown to have marginal sen- sitivity for sampling periods of 24 hrs. or less, while membrane- type

samplers were determined to have a potential for greater sampling rates.

Specifically, the following activities were covered: (1) completed preliminary evaluation of West-type silicone membrane samplers; (2) since

elution was found to be a problem with samplers in (1), two other mem- brane filter holders were designed; (3) relative sampling rates of the

Palmes, West, and NBS (containing a Millipore filter diffusion barrier)

samplers were tested and found to be approximately 1, 8, and 30 cm

3 /

min., respectively; (4) tests on the NBS sampler were initiated to

determine reproducibility, linearity, precision, and other factors.

On NO- personal exposure monitors, work efforts were next focused

on evaluation of alternate sampler designs as a take-off from the Westtype silicone membrane sampler. Work on the latter type of sampler was discontined due to elution problems. In addition, erratic results with

this type of sampler were observed recently by other workers. Using a Nuclepore filter holder containing either a Millipore cellulose-type or teflon filter diffusion barrier backed by a polyester mat impregnated

with N0n absorbent (triethanolamine) also produced, erratic results.

Millipore filters were evaluated due to their higher flow permeation

rate. However, preliminary results using a Nuclepore polycarbonate

filter backed by a perforated metal screen (coated with trei thanolamine)

were much more precise. Evaluation of this more promising sampler was continued. This sampler appears superior to both Palmes and West-type

devices.

While work with Millipore filter samplers gave erratic results, the use of a Nucleopore filter backed by a perforated metal screen coated

with triethanolamine gave more precise results. These findings can be

illustrated by the tabular data given below and plotted in Figure 15.

139
I . Mi Hi pore (8 ym) :

ppm

NO,

Exposure

(h.)

(ppm-h)

Integrated

Exposure (B)

Average Amount

Found (A)

(yg) A/B

0.252 24.9 6.27 26.4 4.2

0.252 26.9 6.78 24.3 3.6

0.134 6.2 0.831 21.2 25.5

0.148 4.0 0.592 17.6 29.7

0.095 1.5 0.143 1.09 7.6

0.095 2.42 0.230 2.10 9.1

0.095 3.25 0.309 1.84 6.0

Nucleopore (0.8 ym)

:

0.104 20.3 2.11 6.80 3.2

0.104 7.0 0.728 2.28 3.1

0.104 16.2 1.69 4.65 2.8

0.221 3.0 0.663 2.30 3.5

0.221 6.0 1.33 4.16 3.1

0.064 17.75 1.14 4.32 3.8

0.064 7.13 0.456 1.68 3.7

As can be seen from these results, the A/B results were far more constant for Nucleopore than for Mi Hi pore. Results indicated that the

Nucleopore sampler was more than thirty times more sensitive than the

Palmes device. An alternate diffusion sampler for N0

2

has also been

devised that employs the DuPont Pro-Tek Organic Vapor device with the

charcoal collector strip removed. A grid coated with triethanolamine

was inserted in place of this strip. Preliminary data indicated this

modified device to have a high sampling rate. Finally, an NOo introduction system was constructed to allow N0

2

to be introduced^ nto the

air stream of the wind tunnel to evaluate passive samplers under wind

conditions. It employs a cylinder of NOo and heated transfer lines and

valves that permit N0

2

to flow at a constant rate into a mixing chamber,

where it is mixed witn air and subsequently introduced into the wind

tunnel. This NOo introduction system will be used for final evaluation

of the Palmes diffusion tube sampler.

Further testing was carried out using the Nucleopore sampler under

static testing conditions. The final phase of work on the evaluation of

personal exposure samplers for nitrogen dioxide will involve dynamic

tests performed in the wind tunnel.

2. Particulates

In work on particulate personal samplers, a detailed NBS FY-1979

activities report ("Personal Ambient Aerosol Sampler") was prepared and

submitted to the EPA Project Officers for this part of the project. In addition, the test system (wind tunnel and associated equipment) fabrication

140
141
was completed, assembled, and calibrations were initiated. Specifically:

(1) various filters were calibrated for pressure drop and flow rates;

(2) a Spinning Disc Particle Generator has been calibrated; and (3)

calibration work was initiated on an optical particle counter and a Berglund-Lui generator, using the NBS Particle Doppler Shift Spectrometer.

Ammonium fluoroscein was chosen from a number of possibilities as the most suitable aerosol material. This material is widely used, easy

and safe to handle, and provides aerosols having desirable characteristics.

Selection of an appropriate material for aerosol generation was a necessary

prerequisite to series filter and inlet testing using aerosol injection.

The wind tunnel was assembled, and preliminary flow calibration was completed. The wind tunnel blower location was changed, and a grid was added to improve the air flow profile. A dispersion of small particle

size aerosol was tested in the tunnel using oil aerosol and an optical

particle counter. A TSI piezobalance obtained from EPA was found to be

insufficiently sensitive for these measurements. A preliminary cut test

was run on the Tomb-Treaftis Impactor and series filters. Series filters

were selected as the most promising avenue for further aerosol sampling

testing. In addition, extensive flow tests were performed using various

filter holders and filter materials to determine the combination having

the lowest pressure drop.

Extensive weighing tests were made of clean filters. It was determined that relative humidity above 50% affected the filter weights.

Use of a new weighing room for weighing of the filters (Zeflour [Ghi a]

,

Fluoropore [Mi 1 1 i pore] , and Nucleopore) gave precise weights to better

than ± 10 yg. Series filter components were selected and cut tests were

completed. Due to design factors, testing of the Harvard cyclone sampler

cut point was found to be difficult, and testing was delayed until the

absolute sampling efficiency of this sampler could be tested in the wind

tunnel. In addition, extensive evaluations were performed on eight

pumps (including Spectrex, Brailsford, DuPont, and Bendix) for electrical

efficiency, power requirements, and flow fluctuations. These tests were

performed for flow conditions that might reasonably occur for any given

series filter or impactor unit under study. The Bendix BDX-60 (or BDX55) motor-pump unit was selected as the most compatable with the series

filter chosen. An effective pulse dampener was developed and tested,

since the commercial pump units (and the Harvard sampler pump) had

unsatisfactory flow fluctuations. At this point, the project sampler

pump and series filters were selected, and the wind tunnel made ready

for fluoroscein aerosol dispersion testing.

Progress on the NBS personal dosimeter for particulates was presented

at the 13th Aerosol Technology Meeting at the Harvard University School

of Public Health in August 1980, with considerable interest shown by

researchers and commerical firms alike. The demonstrated unit was essentially complete, including case, except for a characterized inlet or head which has been designed and placed under fabrication. Since

flow rate was of a primary concern, the effects of flow rate were measured

for various dosimeter characteristics, such as battery type, battery

drain, filter lot, pressure drop, and filter loading. Options of battery

type and voltage regulation schemes were examined for different measurement

:

142
needs. It was determined that any anticipated filter loadings will not

affect flow rate through the dosimeter, and it was confirmed that loading

of the coarse filter does not affect the size cut characteristics. The

present stacked filter appears as the most optimum sampling arrangement,

owing to its simplicity, inexpensiveness, and its ability to provide

samples for x-ray fluorescence analysis. Large particle (15 pm) injection schemes were tested in the wind tunnel for losses and for test

section. Particle and velocity profiles are being tested for two of

these schemes. Next, inlets will be tested, including and screened

filter faces, the 10 mm Harvard cyclone sampler, and designs by Walter

John (Berkeley, CA) and Klaus Willeke (Cincinnati, OH). The pump and

battery systems selected for the dosimeter are far more optimum than

other sampling systems considered or used in practice, including the

Harvard sampler, both in terms of flow constancy, extended sampling

time, and compactness.

3. Toxic Organics

In the area of evaluating samplers for toxic organics, a detailed

report ("A Survey on Research Needs on Personal Samplers for Toxic

Organic Compounds") was finalized and submitted together with a proposed

FY-1980 work plan to the EPA Project Officers for this project. Work

was then initiated in line with the developed detailed work plan,

approved by the EPA Project Officers.

An exposure chamber was constructed to allow passive samplers to

sample low concentrations of benzene (and other) organic vapors. The

chamber design is similar to the one used for N0

2 sampling. The main

components included a cylinder con-taining the organic compound in air,

a supply of pure air (for dilution of the organic), flow controllers and

voltmeters, and a chamber in which the samplers could be placed.

Standard solutions of benzene in CS

2

were prepared at concentrations of

12-100 yg/ml . Analysis by gas chromatography (flame ionization detection) showed good linearity over this range. A benzene solution (ca.

2 yg/ml) was prepared and found to produce adequate response with the

flame ionization detector. Standards prepared at this concentration

level (2 yg/ml) were deemed adequate for the analysis of commerical

passive samplers (e.g. the DuPont sampler). Using a sampling rate of 86

ml /min (DuPont value) it appeared possible that sufficient sample could

be collected at 1 ppm lev^l in 12 minutes; at the 100 ppb level in 2

hours; and at the 10 ppb level in 20 hours. An electron capture detector was ordered for for work with halogenated organics identified for

study (e.g. perchloroethylene)

.

The exposure chamber for organics provided a dilution capability of

about 100:1 at flows up to 8 liters/minute. It has been used with

cylinders containing known concentrations of benzene in air to provide

diluted mixtures for the testing of the DuPont Pro-Tek badge, a diffusioncontrolled sampling device. Results, measured in duplicate runs, are

143
given in Table 20. The charcoal strip in each sampler was desorbed with

1 ml carbon disulfide and the extracts compared with standards of

benzene in carbon disulfide, using a gas chromatograph with flame

ionization detection. A strip of charcoal adsorbent from an unexposed

sampler was used as the blank. The data revealed good precision between

duplicates, but larger discrepancies between runs. Comparison of the

results obtained was made with results expected, based on data supplied

by DuPont at a benzene sampling rate of 86 ml /min. DuPont information

indicated that these devices will give low results when the air velocity

is less than 35 ft. /minute. Calibration curves for benzene in carbon

disulfide were prepared covering concentrations down to 0.7 yg/ml

benzene. Since a survey of five different batches of carbon disulfide

showed some batches to have a measurable interference peak at the

benzene elution peak time, its purity must be examined prior to its use for measurements of low benzene concentrations.

Table 20. Collection Efficiency of Benzene on Commerical Personal

Monitoring Badges

Integrated Amount Amount Collection

Exposure Collected Expected Efficiency

(ppm-hr.

)

(yg) (yg) (*)

9.0 102 149 69

102

3.6 45.1 59.5 78

47.2

1.1 10.19 17.7 56

9.79

0.44 4.71 7.34 62

4.45

Velocity Wind Tunnel Facility for the Evaluation of

Personnel Dosimeters

A low velocity wind tunnel was designed, constructed and characterized.

The tunnel enables us to produce aerosol and gas samples of known component

concentration and flow profiles for evaluation of the efficiencies of

aerosol and gas sampling devices. The tunnel consists of a high efficiency

absolute filter at the inlet, followed by a mixing grid to flatten the

flow profile, and an injection section for the introduction of aerosol or gas samples. The test or sampling section of the tunnel (12 feet

downwind of the injection section) has a 2-dimensional automated traverser, which enables us to accurately position and locate velocity or sample probes in order to measure the velocity and sample concentration

profiles in the tunnel. The maximum velocity is - 3 m/s. The velocity

profile is flat to better than 10 percent in the cross-section of the

tunnel beyond the 2 inch wall boundary layer. There is very low mixing

in the tunnel so that when a point-source injection system is used, we obtain sample profiles that are quite steeply parabolic.

144
For multiple sampler testing we will need to use either multiple

injection or more severe mixing to broaden the sample concentration

profile.

We have used the wind tunnel to evaluate a personal ambient aerosol

sampler (PAAS) that is currently under development at NBS. The two

components of the PAAS--the aerosol sampling/ collection section and the

sampling pump--have been evaluated separately. Eight different pumps

have been evaluated for power requirements, pumping efficiency and flow

stability. A pump has been selected that provides 5-6 liters per minute

for periods greater than the desired sampling period of 8 hours and has

low power consumption (Bendix BDXX55). The pump was tested under load

conditions on the sampler that exceed loading conditions normally found

in field applications.

The aerosol sampler selected is a two stage series filter system

using a 37 mm diameter, 8 ym Nucleopore filter, followed by a high

efficiency teflon filter. The sampler is to divide and collect ambient

aerosol in two size fractions. The first filter (8 ym Nucleopore) will

collect respirable particles (about 2 to 15 ym diameter), and the second

filter (telfon) will collect the remaining smaller particles. The cutoff size (particle size at which the filter is 50 percent efficient) was determined for the Nucleopore filter using monodisperse aerosols generated

by a vibrating orifice aerosol generator. Fluorescein aerosol was used

to enable accurate spectrophotometric determination of low aerosol

concentrations on the filters. The filter collection efficiency for the

Nucleopore filter is presented in Fig. 16 as a function of particle

aerodynamic diameter where aerodynamic diameter is a parameter that

normalizes particles (regardless of shape) in terms of aerodynamic

behavior for a unit density sphere. The collection efficiency for the

first filter is defined as the aerosol concentration on the first filter

divided by the sum of the concentrations on the first and second filter

(total aerosol collected by the sampler). The sampler has the desired

cut-off point of 2-3 ym which does not vary significantly with flow rate

in the range from 4 to 6 liters per minute.

145
100

0 experiment 1

+ : experiment 2

0

Se> >s. 0

050 .. O

•&H

UJ

'd — | h— —+

SS CM

^

—H—— (—

— — 1 CD 00

Aerodynam i

c

ameter, pm

Figure 16. Coarse filter collection efficiency vs. particle size.

146
(2) CALIBRATION AND MEASUREMENT TECHNIQUE DEVELOPMENT FOR UV RADIOMETRY

Participants : H. Kostkowski, R. Saunders

Scope :

The NBS will develop a high wavelength-accuracy spectroradiometer

and a facility at NBS for characterizing and calibrating spectroradiometers, for the measurement of terrestrial irradiance from

direct sunlight between 290 and 320 nm with an estimated uncer- tainty not exceeding 5%. The NBS will use the above facility to

develop techniques for determining the responsivity function for

double monochromators in the 290 to 320 nm region required for the

above stated solar measurements. A ring dye laser will be utilized

for maximizing the cw power available in the 290 to 320 nm region,

so that a data point in the extremely low level wings of the re- sponsivity functions may be obtained with an accuracy of a few

percent, with integration times considerably less than the one hour

currently estimated. In addition, the facility will be set up in a separate laboratory dedicated to spectroradiometer characterizations,

insuring greater flexibility and responsiveness to future needs of

the EPA and the UV-B radiative research community.

The above accomplishments will make it possible for NBS to carry

out the following:

0

Use the high wavelength-accuracy spectroradiometer in the

summer of 1980 to determine the terrestrial irradiance

from direct sunlight between 290 and 320 nm at Gainesville,

Florida, in order to develop and illustrate optimum procedures

for such measurements. These measurements will then be

correlated with the amount of atmospheric ozone at the

measurement site.

0 Characterize and calibrate two spectroradiometers selected

by EPA to be used for direct or hemispherical terrestrial

solar irradiance measurements or measurements of laboratory

sources in the 290 to 320 nm region with an estimated

uncertainty not exceeding 5%, providing that the spectroradiometers and laboratory sources are sufficiently stable.

0 Complete first draft of a guide for performing accurate UV

spectral irradiance measurements of the sun and of various

laboratory sources, and provide consultation to EPA-supported

UV-B radiation effects researchers.
Project Milestones and Estimated Completion Dates

1. Complete design and procurement of high wavelength

accuracy spectroradiometer and laser systems.

(Completed) 8/79

2. Set up test facility and initiate development

of techniques for accurate determination of

spectral responsivity functions in the spectral

region from 290 to 320 nm. (Completed) 12/79

3. Completion of UV-spectroradiometer and the facility

at NBS for characterizing and calibrating spectroradiometers. (Completed) 3/80

4. Complete development and characterization of the new state-of-art spectroradiometer. (Completed) 5/80

5. Test the new instrument and measurement techniques

and conduct filed measurements at Gainesville,

Florida. (Completed) 8/80

6. Complete all data reduction and papers describing

new techniques and results. 4/81

7. Perform additional experiments to address new information derived from the June 1980 field study;

provide consultation and calibration services for

EPA-designed spectroradiometers ; finalize facility

plan at NBS for solar measurements by the advanced

spectroradiometer and measurement techniques. FY-1981

Project Progress-FY-1980

1 . Project Synopsis :

Initial FY-1980 activities focused on completion of the characterization

laboratory and the computer-controlled automation system, and planning

for field measurements at Alex Green's facility in Gainesville, Florida.

A significant discovery was made having direct application to these

measurements, whereby it was demonstrated that the wings of the slitscattering function of a spectroradiometer are significantly less when

measuring coherent light. It should be possible to use this result in

solar measurements by looking at the sun directly (no telescope) utilizing

an entrance slit of about 20 y in width.

Corrections due to scattering should then be significantly reduced.

Alignment and calibration procedures will be more difficult. Nevertheless, initial reaction to the potential benefit of this discovery was considered significant.
The necessary equipment for the spectroradiometer was obtained, and

the instrument was assembled and characterized.

The new spectroradiometer and measurement techniques were tested

and used in very successful field measurements conducted at Gainesville,

Florida during June 1980. Extensive and excellent data were obtained

during the field tests. Reduction and analysis of these data was initiated in August 1980. In addition, NBS participated in the "UV

Radiation Epidemiology Workshop" held at the University of Pittsburgh.

A paper was prepared on the field measurements study in Gainesville,

Florida, entitled "New State of the Art in Solar Terrestrial Spectroradiometry below 300 nm". Reduction of the extensive data taken in the

field study is in progress.

2. Description of the New Spectroradiometer and Characterization

Facility

A high-wavelength-accuracy, automated, portable, photon counting

spectroradiometer has been developed for improving the accuracy of

measurements of terrestrial solar irradi.ance below 300 nm. The instrument was designedly Prof. W. Fastie of Johns Hopkins University and

a number of people in the NBS Spectror&diometry Group and was manufactured

by Research Support Instruments, Inc., and the NBS Instrument Shops.

The major new feature of the instrument is a Fastie-Ebert double mono- chromator made of Invar, and containing two holographic gratings having

300 grooves per mm. The low temperature-coefficient and high dispersion

make possible a high wavelength accuracy. In spite of its short focal

length of 12.5 cm, the wavelength readout is 0.001 nm, setability 0.005 nm and accuracy 0.02 nm. The detector is a selected, bi alkali photomultiplier cooled to -20°C. The photon counting system has a 10 ns pulse pair resolution. Output signals in total counts and counts per

second along with wavelength, ambient temperature, and time are printed

out as well as stored on an 8" floppy disc. Wavelength settings and

integration times are also computer controlled. A specially designed

aperture/filter system makes it possible to replace filters, diffuser or aperture stops rapidly and with a high degree of freedom required for

accurate pointing at the sun. The instrument has been used in extensive

solar observations betwen 287 and 340 nm where the output signal varied

from a few counts to 10 7 counts per second.

Our dye laser UV spectroradiometer characterization facility has

been completed. The heart of the system is a 12 watt argon laser, dye

laser and a frequency doubling section with crystals and temperature

control to provide outputs continuously tunable between 285 and 317 nm with output power varying from 1 to 4 milliwatts in this wavelength

range. The power actually available is about 1/10 that specified and

the contractor is trying to remedy this situation. Nevertheless, it

still has been possible to determine the responsivity function of the

special UV spectroradiometer described above in the vicinity of 290 nm

149
to 10’ 7 of its peak. In addition we were able to detect a significant

wavelength asymmetry in this responsivity function and find a set of

operating conditions for which it was largely eliminated. This was quite important for terrestrial solar measurements in the very steep

ozone cut-off region below 295 nm. The characterization facility was also used in FY 1980 for determining the responsivity of BRH's UV Hazard

Monitor and will be used during the next fiscal year for determining the

spectal responsivity of the new NBS photoelectric pyrometer now being

developed, for characterizing other UV spectroradiometers for the EPA

and for further investigations of slit-scattering functions in the

visible where the dye laser provides continuously tunable lines with

over a watt of power.

The UV photon counting spectroradiometer will be used to establish

a new state of the art for terrestrial solar spectral irradiance mea- surements below 300 nm. This work will be done in collaboration with

Alex Green at the University of Florida, Gainesville. Higher wavelength

accuracy, measurement of the slit-scattering function, spectral deconvolution, a state-of-the-art photon counting system and application of

the measurement equation with respect to all the radiation parameters

are expected to significantly improve earlier efforts and establish

standard procedures for terrestrial solar measurements. In addition,

the Dobson method usually used for ozone determinations will be compared

with the newer Green method. We are now in the process of reducing and

analyzing the large amounts of data taken during June 1980. Several

publications are expected from this effort, including a chapter in the

NBS Self-Study Manual (a comprehensive treatise on radiometry, detailed

enough for self-instruction, and is being published one to several

chapters at a time as an NBS Technical Note in the 910 series).

150
(3) ENERGY-RELATED GAS METHODS DEVELOPMENT

Background

Due to the anticipated marked increase in fossil fuel fired power

plant development, it is necessary to plan effectively for the

development of pollutant gas analysis methods to provide data

quality assurance in pollutant gas emission measurements. During

the past two decades the analysis of gaseous substances has become

critically important. Toxic gases impact the health of the environment, industrial workers, and the general public. At the beginning

of this period, few methods of analysis were available that provided the required accuracy at the usually low concentration levels

of interest. Of the methods developed during this period, almost

all have been relative, depending on gas standards of various types

to achieve the required accuracy of measurement. Regulatory guidelines of the U.S. Environmental Protection Agency for ambient air

quality monitoring, data reporting and surveillance provisions (FR

27558, May 10, 1979) specify that gaseous standards used must be

working standards certified by comparison to NBS gaseous Standard

Reference Materials (SRM's). It is clear that maintenance of NBS

competences for gas analysis and gaseous SRM development represents

a national need for environmental monitoring and research. While

NBS has devoted extensive efforts towards the development and

production of gas standards, it has spent insufficient time on investigations of new and absolute methods of gas analysis. It is

imperative that the established NBS competences in gas analysis and

gas standards production be continued and improved upon to insure

that present and future national needs for data quality assurance

in toxic gas monitoring and research are met. Activities related

solely to replenishment of the inventory of existing NBS gaseous

SRM's will, by itself, be insufficient to maintain the existing

competences in this NBS activity.

An effort is needed to investigate existing absolute methods of

chemical analysis in order to assess their applicability to gas

analysis. In addition, an effort should be directed toward re- fining classical methods of gas analysis (such as volumetric and

gravimetric techniques) in order to apply them to low concentration

gas measurements. Further, some effort should be expended in

investigating totally new measurement principles to determine their

applicability to gas analysis.

The principal NBS activity under this project for FY-1980 has been

an intercomparison of cylinder standards containing atmospheric

concentrations of CCL. The methods used for these standards by

NBS, Scripps Institute of Oceanography , and NOAA-Boulder are gravimetry, manometry, and volumetry, respectively. Accurate C0

2 standars are needed to assess changes in atmospheric C0

2 levels,

which have been found to be on the increase over the last 20 years.

151
There is a national concern for increasing atmospheric CO

2 con- centrations due to anticipated increase in house" effect of COp in

altering global climate. Scripps has provided a broad COp standards

service to the COn measurement community over the years. ^Scripps

has recently requested that NBS assume the COp standards responsibility

by development and maintenance of SRM's for COo in air at atmospheric

concentrations. A discussion of the progress in this intercomparison

and a related activity is given below.

Selected Technical Activities

1 . Standards for Measurement of Atmospheric Carbon Dioxide

E. Hughes, G. Sleater

Since the early 1950s internationally accepted standards for the

measurement of atmospheric carbon dioxide have been traceable to a single set of manometrically analyzed standards prepared by Dr. David

Keeling of Scripps Institute of Oceanography (SIO). Expansion of the

monitoring network and the necessity for assuring a continuing supply of

standards of high accuracy prompted the National Oceanic and Atmospheric

Administration, the Department of Energy, and the Environmental Protection Agency to involve the NBS in a program to produce SRM's equal in

accuracy to the standards maintained by Keeling. The production such

standards requires a method of preparation of laboratory primary standards that are both accurate and reproducible. An uncertainty of

±0.1 ppm for a standard containing 330 ppm was considered the maximum

tolerable error.

A unique mi crogravi metric technique was developed and a set of 14

standards varying in concentration from 290 to 370 ppm were prepared.

The gravimetric technique involves weighing the carbon dioxide contained

in a "micro cylinder" on a semi -micro balance and accurately transferring it to a large cylinder to which a weighed amount of air is

added. The internal consistency of the set was evaluate by intercomparing samples in the set with each other using both gas chromatographic and non-dispersi ve infrared techniques. Painstaking care was taken to assure the highes degree of precision of the measurements. The

results showed that the average of the deviations of the samples from

the predicted value was ± 0.02 ppm and the standard deviation of the

observed value relative to the predicted value was 0.09 ppm. These

standards were then used to analyze three working secondary standard

mixtures of 346.7, 340.0 and 333.3 ppm, respectively.

The three secondary standards were taken to SIO and were analyzed

by that laboratory in common with their own primary standards. A com- parison of the NBS and SIO results is shown in the data below:

152
Sample NBS Value Value Determined at SIO

2

3

346.7 ± .17 ppm

340.0 ± .09 ppm

333.3 ± .10 ppm

346.7 ppm

339.9 ppm

333.2 ppm

The limits shown for the NBS value is an estimate of the uncer- tainty of the concentration of the secondary standard relative to the

primary gravimetric standard. The uncertainty of the value measured by

SIO is not known on an absolute basis but the repeatability of the

measurement is estimated to be about ± 0.1 ppm.

The agreement is excellent considering the complete independence of

approach of each laboratory. However, further work is planned to improve

the precision of the measurements and thereby to determine whether the

slight differences are random errors or biases between the methods. The

most probable source of error in the NBS value would be in the analysis

of the reagent gases while the most likely source of error at SIO would

be associated with volume calibrations. Both of these error sources are being investigated.

. Intercomparison of 0^, NO and NOq Measurement Standards by

Gas Phase Titration

J. A. Hodgeson, A. Fried

Ozone (03

), nitric oxide (NO), and nitrogen dioxide (N0

2

) are critical constituents involved in the chemistry and physics of the

troposphere and stratosphere and are subject to considerable monitoring

requirements. For each of these gaseous constitutents, an individual

measurement standard is currently employed for calibration. Ozone is

measured on an absolute basis by absorption photometry using the known

0

3 cross section at the mercury 253.7 nm line. For NO and N02

the

measurement standards take the form of Standard Reference Materials

(SRM's); NO is gravimetrically prepared in cylinders, while the N0

2

SRM

is a permeation tube. This is the first concerted effort to intercompare gas standards by means of known chemical reactions, in this case employing the rapid, bimolecular reaction,

At low concentrations of 0

3 (sub-ppm levels) and in the presence of

excess NO, the reaction is stoichiometric and the following relationship

holds

Therefore a measurement of any one of the three components (A(N0)

= reacted, A(0

3

) = added, a(N0

2

) = produced) yields a measurement of

the other two.

NO (excess) + 0

3

= N0

2 + 02

.

A(N0) = A(0

3

) = A(N0

2

).

153
In the experimental arrangement, NO from a standard cylinder (50 or

100 ppm) is diluted with clean air by a flow dilution ratio, R = 30 - 100, to obtain an initial NO concentration in the range of 0.5 - 1.5

ppm. The clean air stream passes through a variable 0^ source such that

0^ can be added in increments over the range, 0 - 1 ppm. The output of

tne reaction vessel passes to a sampling manifold where the concentrations

are monitored with calibrated detectors.

Since the NO sample from the cylinder must be diluted, an accurate

determination of the initial NO cylinder concentration requires an accurate determination of the flow dilution ratio, R. Considerable

effort was expended in verifying the measurement of the NO and clean air

flows. A wet test meter calibrated gravimetrically was employed for the

air flow and the calibration of this meter was verifed at the Primary

Flow Calibration Facility of the NBS Fluid Engineering Division. The

low flow rate NO measurement was performed with a soap bubble meter, a mercury sealed piston device and a wet test meter, the accuracy of which

was confirmed at the Primary Flow Calibration Facility. The estimated

uncertainty in the measurement of R is less than one percent.

Our initial objective was to provide an independent analysis of the

NO SRM based on photometric 03 measurements. Our initial gas phase

titration (GPT) measurements .however, gave NO cylinder analyses which

were consistently 4-5 percent lower than the gravimetric analysis.

This in turn indicates that the A (0^ ) photometric measurement is less

than A(N0) based on gravimetric calibration by the same amount. In an attempt to resolve this bias, a specially designed optoacoustic detector

was constructed to measure the N0

2 produced. This detector uses an argon-ion laser for excitation or the N0

2

visible absorption band. The

detector is calibrated with an N0

2 permeation tube standard and has a minimum detection limit of .005 - .01 ppm. An important feature of the

optoacoustic detector is that it does not respond to NO. Previous

attempts to make similar measurements have used chemiluminescence N0

X

detectors (NO = NO + N0

2

) which measure N0

2 differentially, i.e. NO* - NO = N0

2

. Considerable measurement uncertainty is introduced when NO is

present at higher concentrations, as in the GPT experiment.

A limited number of measurements have been made thus far on N0

2

produced, based on a permeation tube calibration, A(N0

2 )pt, but these

data are revealing. A considerable amount of data have been obtained

comparing A(N0) gravimetric, A(N0) , and A(0o) by photometry [A(0o) ] over the range 0-1 ppm. These data were obtained over a one year time

scale by two independent operators and comprise 15 different GPT ex- periments with 44 valid data pairs. These data sets can be fitted by

linear-regression to yield the following relations:

A ( °3 ) uv

=

( 9 - 957 1 °' 002 ) A ( N °)g + (' 0002 1 •°01 )’ n = 44

A ( N°

2 ) p t = 0-°l ± 0-01) A ( NO

)

g

- (.0052 ± .0055), n = 8

The intercepts are negligible within the uncertainty of the fit.

The precision of the GPT measurements is excellent and reflects the

precision of the flow measurements as well as the stability of the

154
various detectors. The apparent agreement between A(N0) and A(N0

2

) verifies the reaction stoichiometry and that the GPT apparatus is

working properly. We are left with the implication that the 0

3

ultraviolet measurement may be low by approximately 4 percent. This is a larger bias than can be explained by estimates of the uncertainty in the

presently accepted value of the 0* cross-section. We are continuing the

NOo measurements for further verification of the above results. In

addition, a new and improved 0

3 photometer is being constructed to

replace our existing system and an independent 0

3

calibration will be

available soon.

155
(4) ENERGY-RELATED PARTICULATE METHODS DEVELOPMENT

Background

In order to meaningfully address the national concerns for human

health and environmenal impacts associated with assessments of

energy-related air particulate emissions due to increased con- ventional and advanced fossil fuel technologies, improved and

new methods technology is urgently needed to reliably characterize

the chemical nature, particulate size, and anthropogenic

contribution of air particulates. The EPA in its Research

Outlook 1978 (EPA 600/9 78-001) identified aerosols as a high

priority research area, second only to toxic substances. To

illustrate, increased coal combustion is expected to contribute

greatly to sulfur and nitrogen oxide emissions during the next

15 years. These gaseous emissions are precursors to higher

toxicity secondary pollutants, such as sulfate and nitrate air

particulates. In addition, human health impacts are of high

concern since large size aerosols may be captured by sinus and

throat mucus membranes and affect the digestive tract; while

small size aerosols and fine particulates may be carried deep

into the lungs with serious health consequences (e.g., emphysema,

lung cancer). Further, increased particulate emissions are implicated in the deterioration of visibility and dramatic

regional consequences of "acid rain," which episodes appear

to be increasing in frequency. It is hence not suprising that

increased attention is being given to methodology research to

improve the characterization and quantitation of air particulate

emissions.

Projected Milestones

In FY-1980, NBS activities under this Task Project (supported

exclusively by the E/E EPA-NBS Program) have included:

0 Development of the NBS Particle Doppler Shift Spectrometer

for aerosol size measurements and characterization of

aerosol generators.

0 Development and characterization of an instrument for

real-time analysis of sulfate aerosols.

0 Development of low-level 14 C measurement and 14 C/ 12 C

measurement methodology for assessments of biogenic

versus fossil carbonaceous pollutant sources.

0

Measurement methodology development for characterization

of polycyclic aromatic hydrocarbons on air particulates.

156
Selected Technical Activities

1 . Particle Doppler Shift Spectrometer (PDSS )

D.S. Bright, R.A. Fletcher, I. Chabay, R.L. McKenzie

A vacuum sample tube was designed and installed in the PDSS in order to

extend particle size measurements into the submicron range. Although

the vacuum requirements are not extreme (down to a few torr), the

stability of the system in holding a vacuum is critical due to the dependence of the slip correction and mean free path upon pressure. Extensive

leak testing has been completed during which several components of the

system (a pressure gauge and two high vacuum valves) were found to be

defective and were replaced. The system is now ready to begin meements

of the slip correction and very low Reynolds number air flow phenomena,

and of submicron aerosols.

Experimental studies of the extremely small particle-induced fluid flow

phenomena (fluid flows of the order of 0.01 cm/s) have been completed,

and a theoretical model has been developed through the exact solution of

the Navier-Stokes equation in the low Reynolds number regime. The theoretical

model agrees well with the experimental results. These studies are now being

prepared for publication.

The PDSS has been used to help characterize the properties of

several aerosol generators. Our experience with the spinning disk

generator shows it to be useful for generating mono-dispersed di octyl phthalate aerosols in the size range greater than about 15 micrometers,

but not as useful as the Berglund-Lui vibrating orifice generator in the

less-than 15 micrometer range.

Studies have also been made on the properties of ammonium fluorescein

for use as an aerosol material. Aerosols generated by the vibrating

orifice from a solution of ammonium fluorescein are solid, spherical

particles, and have optical properties that allow ready detection at

trace levels by spectrophotometric techniques. They have very low

volatility and a high melting point, making them suitable for electron

microprobe and x-ray analysis. In addition, ammonium fluorescein is

considered to be non-toxic. Measurement of the diameter of ammonium

fluorescein particles generated using the vibrating orifice generator

has demonstrated that the size of the aerosol can be predicted and

controlled by the molarity of the fluorescein solution used in the

generator.

2. Measurement of Ambient Sulfur Aerosols By a New Fast Response

Flame Photometric Instrument

R.L. McKenzie, D.S. Bright, R.A. Fletcher

Work continued on the characterization and optimization of the

pulsed precipitator/flame photometric detector (FPD) aerosol sulfate

measurement technique. As indicated in the preceding report, we made an evaluation of the feasibility of doping the hydrogen gas with S0

2 or

ethyl mercaptan in order to increase the total FPD response into a range

157
where Lhe instrument is more stable, and to increase the sensitivity of

the response. The sensitivity of the system is a function of the total

signal, because the FfjD response (R) is nonlinear with sulfur concentration^); ( i . e . , R«[S] , where n = 1.8, therefore Sens. = ,tvt « n[S]j. We have experimentally verified this prediction; vtz., an increase in total sulfur concentration of a factor of 2.6 is

predicted to give an increase in sensitivity of 4.7, in good

agreement with an observed increase of 5.1.

An important limitation in the application of the FPD for airborne

sulfate particulate measurement is the slow response time of the burner

to changes in sulfur concentration. The rise time for 90 percent of

full equilibrium response is about 15 seconds, and the fall time is 2.8

seconds. For a precipitator operating frequency of 0.2 Hz we can obtain

only 60 percent of the potentially available response. This is equivalent

to a loss in sensitivity of almost 50 percent. We therefore have looked

for better burner designs. We recently evaluated a burner and detector

system built by Dr. Don Stedman at the University of Michigan and found

that it was much faster (rise time = 1 sec; fall time =0.2 seconds).

We will obtain this instrument through a collaborative study arrangement,

evaluate the burner for sensitivity, and optimize it for application

with the pulsed precipitator technique. Table 21 shows a comparison of

the percent of full response vs. precipitator frequency for the instrument

we have been using, and for the University of Michigan burner/detector.

Table 21

Recovery of Potentially Available Response vs. Precipitation

Frequency

Frequency (hertz)

.2

.5

1.0

2.0

4.0

Percent of Full Response

Meloy

a FPD U. of Mich. FPD

60

17

5

2

100

85

65

30

10

Q

In order to adequately describe materials and experimental

procedures, it is occasionally necessary to identify conmerci al

products by manufacturer's name or label. In no instance does

such identification imply endorsement by the National Bureau of

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

158
The development and characterization of the Pulsed Electrostatic

Precipitator-Flame Photometric Detector (PEP-FPD) system for the measurement of ambient level aerosol sulfur concentrations has been completed

this year and a final report to EPA is in the review process. The basis

of the technique is the use of the PEP to selectively modulate the

aerosol component of the sample while leaving the gas phase component

unaffected, resulting in a signal from the detector (FPD) which has two

separable components corresponding to the particle and gas phase sulfur

concentrations. Because the FPD response to sulfur concentration is

non-linear (Response ^[S]

n where n = 1.5 to 2 depending on various flame

and flow parameters) the sensitivity of the FPD is a function of the

total sulfur concentration in the sample. The following data shows the

sensitivity (dl/dS) and sensitivity relative to sensitivity at 1 ppb for our FPD.

[S] (ppb) dl/dS (amp/ppb) dl/dS relative to 1 ppb

1 1 .42 x 10" 10

(1)

5 4.81 x 10" 10 3.4

10 8.13 x 10" 10 5.7

50 2.75 x 10~ 9 19.4

100 4.65 x 10" 9 32.7

200 7.86 x 10 9 55.4

500 1.57 x 10‘ 8 110.8

1000 2.66 x 10" 8 187.3

One consequence of this operational characteristic is that it is possible

to increase the sensitivity of the PEP-FPD system by increasing the total

sulfur concentration in the flame. We have verified this by adding a constant concentration of CH 3 CH 2 SH to the hydrogen. A second consequence,

however is a complication of data reduction when one is attempting to

measure more than one sample component because the sensitivities are related to total sulfur concentration, not to sample component concentrations. We have solved this problem by developing a data acquisition/

reduction procedure that enables us to achieve simultaneous measurement of

aerosol and gas phase sulfur concentrations with sensitivities of 0.2

ygm S/m 3 and 1 ppb respectively. Initial data comparison from an intercomparison study shows a very high correlation coefficient with data

obtained by a dichotomous sampler-x-ray-fl uorescence system.

We have shown the major limitation in response time of the technique

is in the FPD. (The commercially available FPDs have > 60 sec rise

times and % 1.5 sec fall times.) We have completed characterization of

a new FPD design which has symmetric rise and fall times of less than one

second. This faster response time means the PEP-FPD system will be

capable of real-time measurements of ambient S0 2 /S0 4 concentrations under

conditions where the concentrations are dynamic, such as in plume traverses.

Additional research will be needed to improve the sensitivity and flow

stability of the fast-flame FPD to its full potential, though it now is

comparable to commercially available FPDs in those respects.

159
3. Radiocarbon as an Environmental Trace

L. Currie, G. Klouda

a. Applications

The use of mini radiocarbon measurements with 5-10 mg (carbon)

environmental samples (gases, atmospheric particles, sediment) has

continued with the objective of utilizing the natural 1

4

C/ 1

2

C ratios to

distinguish between biogenic and fossil pollutant sources. Important

progress has been made in our understanding of the source of carbon- aceous particles, especially of those collected in urban areas, through

several cooperative studies with industry* and universities**. A

critical element in these investigations has been the utilization of

sample selectivity (chemical and physical) in combination with the

radiocarbon measurements. That is, because small samples can be used, we have been able to increase the "information content" of our mea- surements by examining samples that have been preselected according to

geographical region, known activities, chemical nature, and stable

isotopic composition. A summary of our recent radiocarbon results,

together with an indication of these critical supporting data, is given

in Figure 17. The general conclusions to be drawn from these studies

are (i) urban particles tend to show predominately fossil carbon (though

with a non-negligible biospheric contribution); and (ii) particles from

remote locations contain less organic carbon, which is primarily biogenic.

An extremely important exception occurred in the Portland Study***, where

the combustion of biospheric material (field, slash, and residential

wood burning) led to the first observations of urban carbonzceous

particles containing up to 100 percent biogenic carbon. These results

have caused us to focus on the air pollution potential of residential

wood combustion - a problem which will be a subject of our continuing

studies (see Figure 18).

b. Research Advances

Research activities have been directed toward the analysis of

atmospheric gases, high accuracy natural radiocarbon measurements,

chemical -mathematical investigations of the Radiocarbon Dating Calibration Curve, and extension of the state of the environmental radiocarbon art to microgram samples using Accelerator Mass Spectrometry.

Work with the atmospheric gases is still in the initial stages; thus

far milligram quantities of atmospheric methane**** have been extracted

for radiocarbon measurement. High accuracy radiocarbon measurements are underway in connection with calibration of the new NBS International

Radiocarbon Dating Standard, and concomitant chemical-statisi tical

investigations have been performed in cooperation with the Australian

National University on an International Laboratory Intercalibration exercise

involving some 20 laboratories and three calibration materials (Oxalic Acid,

1850 Tree Rings, Sucrose). Evaluation of the fluctuations of the Radiocarbon

Dating Calibration Curve is underway in cooperation with the Statitis tical

Engineering Division of NBS under the auspices of an international committee

* General Motors, Global Geochemistry Corporation.

** Oregon Graduate Center, Colorado School of Mines, University of Washington.   The Portland Aerosol Characterization Study measurements were carried

out in cooperation with the Oregon Graduate Center and the Oregon Department1 of Environmental Quality. ** ** The methane study, of interest for climatic reasons and to learn about

man's perturbation of the carbon cycle, is being carried out in . o: cooperation with N0AA (Air Reserves Lab).

160
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162

Bangor,

ME: 8

jug/m 3

(Inventory)

Portland,

OR:

24

yg/m 3

(radiocarbon)
formed for this purpose. Information to be derived includes the assess- ment of accuracy, development of an accepted calibration curve for

accurate dating, and geophysical model information for the assessment of

past climatic variations. Studies initiated in 1979 show outstanding

promise for the analysis of extremely "old" and extremely small samples.

Our exploratory work, which utilized the NBS variable geometry isotope

separator and the University of Rochester Tandem Van de Graaff Accelerator,

demonstrated the feasibility of measuring natural radiocarbon in the 10

yg range. All of the above activities are intended to increase our ability to extract reliable information on anthropogenic and natural

contributions to both environmental pollutants and chemically-induced

climatic perturbations, now and in the past.

c. Statistical Evaluations of the International Radiocarbon Cross

Calibration Exercise, and of the Natural Radiocarbon Fluctuations

High accuracy natural radiocarbon measurements are of critical

importance in a number of fields, ranging from archeology to climatology

to environmental science. In addition to our current activities related

to the calibration of the new International Standard for Radiocarbon

Dating (replacement for SRM 4990B), we have contributed to the numerical

evaluation of interlaboratory data representing a) high precision measurements of homogeneous primary and secondary natural radiocarbon standards,

and b) the "calibration" relationship between radiocarbon concentrations

and calendar age as deduced from dendrochronology (tree ring measurements). The first activity is important for assessing the relative

activity of the three "standards" and for identifying error sources and

limits (random and systematic) among the best laboratories internationally.

Deliberations on the second topic culminated in the organization of the

International Committee for the Calibration of the Radiocarbon Time

Scale, to which NBS scientist, Lloyd A. Currie, is an advisor. The fine

structure of the radiocarbon dating calibration curve — i.e., long-term

trends and short-term fluctuations about the simple exponential decay

model -- is important for two major reasons: a) fine structure must be

adequately evaluated/fitted to achieve accurate dating, b) modeling of

the fine structure provides a means for us to learn more about the

history of the earth (climate, environmental changes, ocean circulation,

solar activity, etc.).

i. Exploratory Analysis of the International Radiocarbon

Cross-Calibration Data: Consensus Values and Interlaboratory Error

Data from the international cross-calibration exercise have provided

an important opportunity to assess the state-of-the-art of high-precision

natural radiocarbon measurement and to derive consensus values for two

relatively pure and homogeneous materials relative to the international

radiocarbon dating standard (NBS Oxalic Acid, SRM-4990B). Performance

163
was good: some fifteen laboratories returned results for the two independent ratios -- Australian National University Sucrose/Modern Standard

(S/M) and 1850 Wood/Modern Standard (W/M) -- with a typical imprecision

(standard deviation) of about five percent per mill; and the distribution

of results was relatively narrow. The primary limitations encountered

were incomplete laboratory data and variable reporting practices.

Analysis of the data led to the following observations:

° Imprecisions (standard deviations) reported varied from about two

percent per mill to eight percent per mill, with one laboratory

reporting 28 percent per mill. Most, but not all, imprecisions

represented counting statistics only.

° Apparent blunders (large deviations from consensus values) occurred

in a few cases, especially for estimates of the ratio S/M.

° "Laboratory error," o -- i.e., a non-Poisson error component -- A was estimated from the data distributions for both sample ratios.

Results were similar: for S/M, 6 = 3.5 percent per mill; for

A

W/M, d = 1.8 percent per mill. These error estimates, though

A

rather uncertain because of the limited number of degree of

freedom, are consistent with earlier estimates, and the may

'reflect the accuracy limit for current counting techniques.

° Consensus ratios, following the use of exploratory techniques to

identify blunders, and taking into account "laboratory error" and

varying Poisson imprecision, were A

14

C = 508.1 ± 2.0 percent per

mill (1850 Wood, age-corrected for decay to 1950). (Uncertainties

represent one standard error, and both S and W are normalized to

6

13 C

= -25 percent per mill).

Further results of the evaluation include 6 13 C distributions and the

search for measurement method-, sample nature-, and isotope fractionationrelated effects. (See Figure 19 for histograms of the intercomparison

results)

.

ii. Calibration of the Radiocarbon Time Scale

Evaluation of the structure of the radiocarbon calibration curve is

critically important both for accurate dating (as shown in Figure 20

)

and for geophysics and climatology (Figure 21 ). At the present time,

because of the remarkable precision of natural radiocarbon measurements

and the unique time (8000 year) record provided by dendrochronology,

radiocarbon is the only radionuclide capable of giving us direct information on past fluctuations in solar activity. When combined with geophysical

modeling and ice core measurements of the ancient atmosphere (C0

2 ), the

14

C variations will yield further insight into the history of the carbon

cycle and prognosis for "the CC^ problem."

164
CROSS-CALIBRATION HISTOGRAMS

(corrected deviations, in °/oo)

- S/M

530 q W/M SIW

525

520 10 s 525 q

515 s 5 q 520 G

0

k m

510 A G k 0 d j L 515

505 E FL 0 -5 A B E G h 510 A E F

500 B d m R -10 F k 0 505 B

495 h j -15 m P 500 d h L

490 495 c j P s

485 I

480 P

i

• S, M, W = Sucrose, Modern Standard, Wood

• CJj = 2°/oo - 4°/oo (Cap.); 5°/oo -8°/oo (Lower Case)

Figure 19 . Histogram of the radiocarbon ratios for ANU sucrose (S), 1350

wood Of) and the modern standard (M; 0.95 x NBS oxalic acid).

Numerical scales are expressed as deviations (in parts-perthousand) from unity from each of the three ratios; and

laboratories are coded alphabetically.

165
CONVENTIONAL

RADIOCARBON

DATES

IN

RADIOCARBON

YEARS

BEFORE

PRESENT

2100

±

40

B.P.
RADIOCARBON

AND

SOLAR

ACTIVITY s i s s

UJ

r-<O

167

Figure

21.

Correlation

of

radiocarbon

fluctuations

with

solar

activity

(sunspots)

and

climate (

10O

In

The

upper

f19

ure

Is

taken

from:

Eddy,

J.

A.,

The

Maunder

Minimum,

Science

192,

1189

(1976).

The

lower

figure

is

taken

from

figure

on

p.

615:

Mathews,

S.

W.,

What's

Happening

to

Our

Climate,

National

Geographic

150,

576

(Nov.

1976).
Objectives of the International Committee are to assemble high

quality data and to utilize geophysical and statistical -mathematical

approaches to "fitting" the data. More specifically, the Committee seeks

to identify means for combining all (reliable) 14 C measurements of treering dated wood specimens into a single radiocarbon scale calibration

scheme, preserving as much of the high frequency components as seem warranted by the data. During the past year cooperative efforts by

L. A. Currie (Center for Analytical Chemistry), C. Spiegelman (Center

for Applied Mathematics), and J. C. Lerman (Univ. of Arizona) have

produced important insights into measurement and interlaboratory errors

(see also part 1, above), assumed functional models, and best estimates

for the calibration curve and its uncertainty band.

d. Advances in Small Sample Radiocarbon Measurement Techniques;

Application to the Assay of Individual Atmospheric Chemical Species

During the past year the NBS program to utilize natural radiocarbon

as a tracer for sources of carbonaceous pollutants has been directed

toward a) fundamental advances in measurement and data evaluation techniques

and b) critical studies of urban air pollution episodes (such as the

Denver "brown cloud") and basic investigations of sources of atmospheric

gases and particles. The importance of these investigations rests upon

the impact of both natural and man-made carbonaceous contaminants on health, stratospheric ozone, and climate. The success of this program,

the only such program extant, is due to the ability of NBS to perform

reliable radiocarbon measurements on ambient samples containing microgram

to milligram quantities of carbon.

Measurement advances are continuing through the development of

miniature gas proportional counter and nuclear accelerator ("atom-counting")

techniques which provide sensitivity gains of 102 to 10 5 compared to

conventional radiocarbon dating techniques. Important meetings treating

these topics (among others), organized by individuals in the group,

included an ACS Symposium ("Nuclear and Chemical Dating Techniques",

March 1980) and a meeting at NBS (August 1980) on sample preparation for

accelerator measurements. Our work with the accelerator, which last year

demonstrated the capability of precise measurement using less than 40 yg

(carbon) of the new international radiocarbon dating standard, is continuing with studies in alternative source preparation methods, isotopic

enrichment, and baseline tests with the first "dedicated" tandem accelerator constructed exclusively for atom-counting measurements. This

particular machine is considered an National Science Foundation

Regional Facility, and it will be located at the University of Arizona.

The accelerator approach will make possible the radiocarbon assay of

pg quantities of individual hydrocarbons and halocarbons, and individual

chemical and size fractions of non-urban atmospheric particulates.

168
Applications to urban pollution and source studies of carbonaceous

particles have centered on vegetative burning in the Portland, Oregon

region, vegetative vs. oil shale aerosol contributions in a remote Utah

location, urban pollution in Los Angeles and Denver, and an international

effort (joint US - USSR AFAEX-79 project) to investigate "processes and

mechanisms of formation and transformation of natural aerosol" in a remote forested region in the Soviet Union. In all of these studies,

which were broadly interdisci pi inary in nature, our group provided the

only isotopic data; and the natural radiocarbon results yielded the only

unique measure of the biogenic (non-fossil) contribution. This was especially important in the Denver and Portland studies where as a result of our measurements it was concluded that residential wood burning

constituted one of most significant sources of inhalable (< 2.5 urn) and

visibility-reducing particles. In Denver for example, it was concluded

that 18 percent of the visibility reduction of the winter time atmosphere

arose from wood burning. Furthermore, 39 percent of the most effective

visibi ty-reducing species -- elemental ("graphitic") carbon -- has been

ascribed to wood burning.

It should be noted that the foregoing regional studies have included

considerable data on chemical and physical characteristics of the ambient

particles, together with supporting emission inventory and meteorological

data. Although radiocarbon techniques provided the only direct measure

of contemporary carbon, the other (indirect) indicators supported the

conclusions from radiocarbon measurements in every case. A major challenge exists in selecting and evaluating the entire multidimensional data

patterns from such experiments; this need formed the basis for the first

Receptor Modeling Workshop (March 1980 in Durham) and the resulting

committee on chemical mass balance and multivariate analysis methods of source reconciliation. Our program at NBS has been expanded to include

such modeling efforts, in cooperation with NBS Center for Applied Mathematics. The combined use of isotopic data^( 13 C and 14 C) with particle

size and chemical data (pyrolysis mass spectrometry, inorganic composition

and elemental vs. organic carbon) has, in fact, been an intrinsic part of

the above urban and remote particulate studies.

A summary of our recent radiocarbon measurements, which now include

atmospheric gases as well as particles, is given in Table 22. Future

work will be directed toward further sampling of selected gases (hydrocarbons, carbon monoxide), sources of urban run-off and sediment studies,

high-altitude sampling, investigations of arctic haze and climatological

consequences, and paleoatmospheric (isotopic) composition via ice core

samples.

169
Recent

Radiocarbon

Result

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Residential

wood

combustion
4. Organics on Air Particulates

Analytical methods were evaluated for the isolation, separation,

and identification of polycyclic aromatic hydrocarbons (PAH) in urban

air particulate matter. These methods have been employed for the

qualitative characterization of the PAHs on SRM 1648 (Urban Air

Particulate Matter).

An important part of this methodology is the use of normal phase

high-performance liquid chromatography (HPLC) on an ami nosilane column

to isolate PAH fractions according to the number of condensed aromatic

ring [Anal. Chem. 49, 2306 (1977)]. The normal phase liquid chromatogram

of the analysis of the urban air particulates (SRM 1648) is shown in

Figure 22 • Each of the numbered fractions was then analyzed by gas

chromatography/mass spectrometry (GC/MS) and reverse-phase HPLC with

fluorescence detection for identification of the PAH. The GC analyses of

fractions 3, 4, and 5 are shown in Figure 23 . The isolation of PAH

fractions in this manner allows identification of many minor components

in the mixture which would otherwise be obscured. The PAHs identified

in SRM 1648 are summarized in Table 23- Reverse-phase HPLC analyses

of the fractions using fluorescence detection confirmed the identities

of many of the PAHs. The liquid chromatogram of the analysis of fraction

4 is shown in Figure 24.

Several different organic solvents have been investigated for

ultrasonic extraction of the PAHs from the particulate matter ( i . e .

,

cyclohexane, methylene chloride, methanol, and tetrahydrofuran) . There

are numerous reports in the literature of the use of cyclohexane for

these extractions. In our studies the polar solvents appear to be more

effective in removing the PAHs from these particulates. However, these

solvents also remove additional organic compounds (i.e., those more

polar than PAHs) which create additional problems in the isolation of

the PAHs. The analytical methodology is being modified to solve these

problems.

171
Inject

Urban Air Particulates • Normal Phase HPLC

TIME f ill )

Figure 22 . Normal phase liquid chromatogram of PAH extracted from

urban air particulates. Column: semipreparative

yBondapak NH2 . Detection: UV absorbance at 254

nm. Conditions: n- hexane at 1 mL/min. Numbers

indicate fractions collected for subsequent . analysis and the PAH structures indicate elution

times for these representative compounds.

172
Fraction 5

figure 23.Cas chromatograms

of fractions 3, 4,

and 5 from urban

air particulates,

(see figure 8)

Column: SE-54

WCOT glass capillary, temperature

programmed from

'200-270° at 2°/min.

L

173
Table 23

PAH's Identified in Urban Air Particulate Matter

(SRM 1648)

Fraction 2

Phenanthrene

0

Anthracene*

3

Methyl phenanthrenes/anthracenes (4)

(probably methyl phenanthracenes)

4H-cyclopenta(def) phenanthrene

Cg-phenanthrenes/anthracenes (6)

Methyl -4H-cyclopenta(def ) phenanthrene

Fraction 3

Fluoranthene*3

n b

Pyrene

Methyl fluoranthenes/pyrenes (5)

Benzo[a]fluorene

Benzo[b]fluorene

Cg-Fluoranthene/pyrenes (2)

Benzo[b]naphtho[2,l -d] thiophene

Benzo[c]phenanthrene

Benzo[ghi]fluoranthene

Cyclopenta[cd]pyrene

Benzacenaphthy 1 ene

Unknowns of molecular weight 230 and 234

174
Fraction 4

Benz[a]anthracene

b

Chrysene*

3

Tri phenyl ene

b

Methyl benz[a]anthracenes/chrysenes/tri phenyl enes (3)

(1 -methyl-, 2-methyl-, and 3-methyl chrysene)

13

Binaphthyls (3)

C

2

-benz[a]anthracenes/chrysenes/triphenylenes (2)

Methyl bi naphthyls (3)

Quarterphenyl

Unknowns of molecular weight 240 and 278 (3)

Fraction 5

Benzo[b]f1 uoranthene*

3

Benzo[k]fluoranthene b

L Benzo[e]pyrene°

Benzo[a]pyreneb

Perylene*

3

Fraction 6

Indeno[l ,2,3-cd]pyrene

b

Benzo[ghi]perylene b

a Identities of specific isomers based on mass spectra and gas

chromatographic retention time.

b Identity confirmed by HPLC and fluorescence spectroscopy

.

175
Urban Air Particulates - Fraction 4

Reverse Phase HPLC

8

j° 9

t° 100 % CHjCN in WATER

0 10 20 30 40 SO

TIME { min )

Figure 24. Reverse phase liquid chromatographic

analysis of fraction 4 from urban air

particulates (see figure 8)

.

Column: Vydac 201TP reverse phase.

Detection: UV absorbance at 254 nm.

Conditions: linear gradient from 70-100

percent acetonitrile in water at ll/min

at 1 mL/min.

176
(5) ENVIRONMENTAL ASSESSMENT

Participants : W. Zielinski, T. Flynn, J. Moody, R. Burke, D. Way

Background :

An Interagency project was developed in FY-1980 between NBS and

the Department of the Treasury's Bureau of Engraving and Printing

(BEP) at the request of BEP. This project, entitled "Provide

Assistance to BEP in Assessing Potential Environmental Concerns

and Prepare a Plan of Action Based on this Assessment", involves

specific NBS competences in analytical chemistry and chemical

engineering.

Activities planned under the established work plan for FY-1980

in analytical chemistry included: (a) the identification of

BEP operational areas for chemical analysis; (b) chemical analysis

of samples withdrawn from these areas for inorganics identified

under the EPA hazardous wastes list; (c) development of a survey

report on BEP's chemical inventory log to assess any potential

environmental concerns on chemicals used in BEP operations; and

(d) provide technical assistance to BEP in its establishment of

protocols for the management of specific wastes, as appropriate,

to conform to EPA hazardous wastes guidelines.

Activities planned under the established work plan for FY-1980

in chemical engineering included: (a) the identification of

BEP priority operational areas for chemical engineering evaluations

related to potential environmental concerns, including the

quantitative determination of operational capacities (present

and potential) and the development of mass and energy balances

for the priority areas; (b) carry out a detailed quantitative

chemical engineering assessment the Dal -Mar press wash and

effluent treatment system; (c) develop preliminary details for

chemical engineering assessment of other areas identified by BEP;

and (d) provide technical recommendations to BEP based on chemical

engineering evaluations to enhance BEP's control and efficiency

of operational systems.

NBS analytical chemistry activities related to environmental

assessments for BEP are coordinated through the NBS Gaithersburg,

Maryland facility in its NML Office of Environmental Measurements

and Center for Analytical Chemistry (W. Zielinski, J. Moody,

R. Burke), while NBS chemical engineering activities are carried

out by chemical engineers at the NBS Boulder, Colorado facility

(T. Flynn, D. Way).

177
Project Progress-FY-1980

The following accomplishments were made in FY-1980 on this project:

0 Finalization of FY-1980 work plan for chemical assessments and

chemical engineering.

0 Completion of survey of BEP chemical inventory log.

0 Completion of preliminary chemical analyses on levels of the eight

inorganics on the EPA hazardous wastes list (Hg, Cd, Se, As,

Cr, Pb, Ag, Ba) on samples obtained from various areas at BEP.

0 Completion of a detailed preliminary chemical engineering

evaluation of BEP's Dal -Mar system.

0 Establishment of preliminary data for chemical engineering

evaluation of other BEP operational systems.

0 Development of an approved work plan for FY-81 , covering a continuing chemical analysis assessment and assistance towards

making BEP self-sufficient in its analytical operations, chemical

engineering assessment of additional areas identified by BEP,

and including chemical engineering development for computer

simulation of engineering processes at BEP to provide BEP with

an internal control and flexibility for its processes.

178
PUBLICATIONS

McClendon, Lottie T. , "A Summary of Oil Shale Activities at the National

Bureau of Standards, 1975-1979," EPA 600/7-80-125, June 1980.

Kirchhoff, William H. , "NBS/EPA Energy Environment Semi-Annual Report

to EPA," July 1979.

May, Willie E. , "Development of an Aqueous Trace Organic Standard Reference

Material for Energy Related Applications," EPA 600/7-80-031,

February 1980.

Kirchhoff, William H. , "NBS/EPA Energy Environment Semi-Annual Report

to EPA," May 1980.

Pella, Peter A., "The Development of Potention Thin Standards for Calibration

of X-Ray Fluorescence Spectrometry," EPA 600/7-80-123, June 1980.

Kingston, H. M. , "Quantitative Ultratrace Transition Metal Analysis of

High Salinity Waters Utilizing Chelating Resin Separation,"

EPA 600/7-79-174, August 1979.

MacCrehan, W. A. and Durst, R. A., "Assessing the Environmental Impact of

Fossil-Fuel Based Energy Sources," EPA 600/8-79-211, November 1979.

Schwarz, Fred P. , "Measurement of the Solubilities of Slightly Soluble

Organic Liquids in Water by Elution Chromatography," Anal. Chem.

52, 10-15 (1980).

Zielinski, Walter L. , "Utility of High-Temperature Thermotropic Liquid

Crystals as Stationary Phases for Novel Gas-Liquid Chromatographic

Separations," J. Chroma togr. 186 , 237-247 (1979).

Zielinski, Walter L. , "Difficult Isomer Separations," Industrial

Research/Development, 178-182, February 1980.

179
/

180

OFFICE OF ENVIRONMENTAL MEASUREMENTS

502.00

'Partially Supported by OEM.

182
Functional Statement

OFFICE OF ENVIRONMENTAL MEASUREMENTS: Responsible for the development

of standards and methods for the measurement of materials in the environment,

such as the concentration of chemical pollutants in air and water, air

"and water flow, and those chemical and physical properties of substances

which affect their ultimate distribution in the environment; the provision

of means for allowing measurement made by other Federal agencies, state,

and local government agencies and industry to be consistent with these

standards; and the provision of critically evaluated data on those

physical and chemical properties of pollutants which affect their

distribution in the environment. The N8S Environmental Measurements

Program thus provides the accuracy and reliability basis for all air

and water pollution, climate related, oceanographic, and toxic substances

measurements made throughout the country by government (Federal, state,

and local) and industry. In addition, this Office coordinates various

international cooperative programs in environmental measurements and

standards.

183
N BS-1 1 4 A ,r'EV. 9-78)

2.Gotft. Accession No.

t

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 81-2280

3. Recipient' $ Accession Wo*

4. TITLE AND SUBTITLE 5. Publication Date

NBSIR "Technical Activities of the Office of Environmental

Measurements"

7. AUTHOR(S)

William H. Kirch hoff

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City, state, ZIP) 13. Type of Report & Period Covered

14. IPIPJ

IS. SUPPLEMENTARY NOTES

Document describes a computer program; SF-185, FIPS Software Summary, is attached.

IS. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant bibliography or

literature survey, mention it here,)

This report summarizes the technical activities of the National Bureau of

Standards' Environmental Measurements Program during Fiscal Year 1980.

This activities fall into four program categories:

1) Water Measurements - Standards Development

2) Water Measurements - Methods Development

3) Air Measurements - Standards Development

4) Air Measurements - Methods Development

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name;

separated by semicolons)

Air; water; environmental measurements; methods; quality assurance; standards

18. AVAILABILITY Unlimited

| j For Official Distribution. Do Not Release to NTIS

r 1 Order From Sup. of Doc., U.S. Government Printing Office, Washington, DC

20402, SD Stock No. SN003-003-

[ I Order From National Technical Information Service (NTIS), Springfield, VA. 22161

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(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

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