Development of Personal Sampling and Analytical Methods for

4 D e v e l o p m e n t of P e r s o n a l S a m p l i n g a n d Analytical

M e t h o d s for O r g a n o c h l o r i n e

Compounds

Downloaded by RUTGERS UNIV on January 2, 2018 | http://pubs.acs.org Publication Date: April 2, 1981 | doi: 10.1021/bk-1981-0149.ch004

K. W. BOYD, M. B. EMORY, and H. K. DILLON Southern Research Institute, 2000 Ninth Avenue South, Birmingham, AL 35255 The need for air sampling and analytical methods for toxic contaminants in the workplace arises from provisions of the Occupational Safety and Health Act of 1970 requiring that regulations be prescribed to limit the exposure of employees to substances or physical agents that may endanger their health or safety. To prescribe such regulations and to ensure compliance, it is necessary to have available sampling and analytical methods suitable for use by employers, Governmental personnel, and others interested in analyzing air samples from the workplace. In 1971 when safety and health standards were established by the U. S. Department of Labor for several hundred chemical substances, there were analytical methods available for some of the compounds, but few were validated to ensure the accurate monitoring of the exposure of workers to these toxic substances (1). Consequently, programs were undertaken by the National Institute for Occupational Safety and Health (NIOSH) to develop and validate sampling and analytical methods. The initial intent was to provide methods that would be useful to industry in measuring the exposures of personnel to potentially toxic materials at concentration levels near the accepted standard levels. Consequently, many earlier methods were developed around the standard levels established by the Occupational Safety and Health Act with validation at, for example, levels ranging from one-half to twice the established standard level (2). Often these methods were not validated at lower concentration levels, say, one-tenth of the original level. The concern over the workplace hazards of chemical substances has increased with the determination that some compounds are carcinogens or suspect carcinogens. Consequently, it has been recommended by NIOSH that several established standards be lowered (3). It is, therefore, very important to develop methods that can be readily adapted to lower standard levels without the need for additional costly and time-consuming research. This presentation describes work performed under contract with NIOSH to develop and validate sampling and analytical 0097-6156/81/0149-0049$05.00/0 © 1981 American Chemical Society

Choudhary; Chemical Hazards in the Workplace ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

50

C H E M I C A L HAZARDS IN T H E W O R K P L A C E

methods

for

three p o t e n t i a l l y

toxic

chlorinated

p o u n d s — h e x a c h l o r o c y c l o p e n t a d i e n e (HCCP), (HCBD), and 1 , 2 - d i c h l o r o p r o p a n e ( 1 , 2 - D C P ) p a t i o n of the p o s s i b l e e s t a b l i s h m e n t f o r t h e s e c o m p o u n d s , NIOSH r e q u e s t e d be v a l i d a t e d o v e r

substantially

organic

com-

hexachlorobutadiene C 4 , J>, 6 ) . In a n t i c i -

of r e l a t i v e l y low standards t h a t the d e v e l o p e d methods

lower ranges of

concentration

l e v e l s t h a n were p r e v i o u s l y c o n s i d e r e d . The r a n g e s o f the m e t h o d s were b a s e d o n t h e d e t e r m i n a t i o n o f t h e l o w e s t a n a l y t i c a l l y q u a n t i f i a b l e l e v e l ( L A Q L ) , d e f i n e d a s t h e s m a l l e s t amount o f a s u b s t a n c e t h a t can be d e t e r m i n e d i n a sample w i t h a r e c o v e r y g r e a t e r t h a n 80% and w i t h a r e l a t i v e s t a n d a r d d e v i a t i o n l e s s t h a n 10%. C o n s e q u e n t l y , s a m p l i n g and a n a l y t i c a l methods were d e v e l o p e d t h a t a r e r e l i a b l e a t l e v e l s w e l l b e l o w t h e c u r r e n t OSHA s t a n d a r d o f 350 mg/m f o r 1 , 2 - D C P and w e l l b e l o w t h e TWA ( 8 - h t i m e w e i g h t e d a v e r a g e ) f o r HCCP o f 0 . 1 mg/m recommended b y t h e A m e r i c a n C o n f e r e n c e o f G o v e r n m e n t a l I n d u s t r i a l H y g i e n i s t s (ACGIH) (7, 8). S t a n d a r d s f o r HCCP and HCBD h a v e n o t y e t b e e n p r o m u l g a t e d . 3


3

The

methods

developed f o r

HCCP,

HCBD, and 1 , 2 - D C P i n v o l v e

t h e c o l l e c t i o n o f v a p o r s o f t h e compounds f r o m a i r w i t h s o l i d s o r b e n t s i n tandem w i t h p e r s o n a l s a m p l i n g pumps, d e s o r p t i o n o f t h e s o r b e d compounds i n a p p r o p r i a t e s o l v e n t s , and a n a l y s i s o f t h e e x t r a c t s by gas chromatography ( G C ) . Method Development To

achieve

optimal s e n s i t i v i t y

and s e l e c t i v i t y ,

it

was

neces-

s a r y t o d e v e l o p t h r e e t o t a l l y s e p a r a t e m e t h o d s , one f o r e a c h c o m pound. I n i t i a l l y , i t was n e c e s s a r y t o d e v e l o p , o p t i m i z e , and c a l i b r a t e a procedure f o r q u a n t i t a t i n g each a n a l y t e . With these s t e p s s u c c e s s f u l l y c o m p l e t e d , c a n d i d a t e c o l l e c t i o n media were screened i n t e s t s d e s i g n e d to f i n d a m a t e r i a l w i t h t h r e e a t t r i butes: (1) a n a c c e p t a b l e s o r p t i o n c a p a c i t y f o r t h e a p p r o p r i a t e a n a l y t e ( i d e a l l y , h i g h enough to p r o v i d e a s a m p l i n g volume o f a t l e a s t 12 L w i t h no more t h a n 5% b r e a k t h r o u g h ) , (2) a n e f f i c i e n t d e s o r p t i o n (>80% r e c o v e r y ) o f t h e compound f o r a n a l y s i s , and (3) a s t a b i l i t y o f t h e s o r b e d a n a l y t e a t room t e m p e r a t u r e f o r a t least

first

7 d without

s i g n i f i c a n t degradation (9).

O p t i m i z a t i o n and C a l i b r a t i o n o f A n a l y t i c a l P r o c e d u r e . The s t e p u n d e r t a k e n i n t h e l a b o r a t o r y was t h e e s t a b l i s h m e n t o f

a n optimum p r o c e d u r e f o r d e t e r m i n i n g H C C P , HCBD, and 1 , 2 - D C P b y GC. ( O t h e r a n a l y t i c a l t e c h n i q u e s were e l i m i n a t e d o n t h e b a s i s o f a preliminary literature search.) Two t a s k s were i n v o l v e d : (1) t h e c h o i c e o f t h e m o s t s u i t a b l e GC d e t e c t o r , c o l u m n , and o p e r a t i n g c o n d i t i o n s f o r e a c h method and (2) t h e c a l i b r a t i o n o f the r e s u l t i n g procedures. D e t e c t o r s e l e c t i o n was r e l a t i v e l y s t r a i g h t f o r w a r d . Because t h e e l e c t r o n c a p t u r e d e t e c t o r (ECD) o f f e r e d s e n s i t i v i t i e s f o r HCCP a n d HCBD t h a t c o u l d n o t b e e q u a l e d b y any o t h e r GC d e t e c t i o n s y s t e m , t h e ECD was e m p l o y e d f o r t h e d e t e r m i n a t i o n o f t h e s e two


4.

BOYD E T A L .

compounds and

(10).

the H a l l

mode) w e r e found t h a t

Organochlorine

51

Compounds

The E C D , t h e f l a m e i o n i z a t i o n d e t e c t o r

electrolytic

conductivity detector

evaluated f o r the determination of 1,2-DCP. the H a l l d e t e c t o r o f f e r e d b e t t e r s e n s i t i v i t y

o t h e r s ; t h i s d e t e c t o r was c h o s e n for 1,2-DCP.

(FID),

( i n the halogen

f o r the development

I t was than the

o f a method


I n c h o o s i n g t h e most s u i t a b l e GC c o l u m n , t h e p r i m a r y c r i t e r i o n e m p l o y e d was t h e d e g r e e o f r e s o l u t i o n o f e a c h a n a l y t e f r o m p o t e n t i a l i n t e r f e r e n t s t h a t c o u l d b e a c h i e v e d u n d e r t h e optimum o p e r a t i n g c o n d i t i o n s f o r that column. T h e compounds c o n s i d e r e d a s p o t e n t i a l i n t e r f e r e n t s f o r e a c h method a r e g i v e n i n T a b l e I . Many o f t h e s e compounds a r e h a l o c a r b o n s t h a t a r e l i k e l y t o c o e x i s t w i t h the analytes i n the workplace. Others possess p h y s i c a l and c h e m i c a l p r o p e r t i e s s i m i l a r to t h e a n a l y t e s . A number o f d i f f e r e n t GC c o l u m n s a n d o p e r a t i n g c o n d i t i o n s w e r e e v a l u a t e d f o r e a c h method b e f o r e optimum r e s u l t s w e r e o b t a i n e d . The o p t i m i z e d o p e r a t i n g c o n d i t i o n s f o r each a n a l y t i c a l method i n c l u d i n g t h e d e t e c t o r s y s t e m o f c h o i c e a r e r e p o r t e d i n Table I I . The r e p o r t e d columns and o p e r a t i n g c o n d i t i o n s y i e l d s a t i s f a c t o r y peak shapes and r e s o l u t i o n o f a l l t h e p o t e n t i a l i n t e r f e r e n t s e v a l u a t e d f o r HCCP a n d HCBD. Two p o t e n t i a l i n t e r ferents—tetrachloro-l,2-difluoroethane and 1 , 2 - d i c h l o r o e t h a n e — c o u l d n o t be s e p a r a t e d from 1 , 2 - D C P w i t h c o n v e n t i o n a l packed columns. T e t r a c h l o r o - l , 2 - d i f l u o r o e t h a n e , a compound w i t h p h y s i c a l p r o p e r t i e s s i m i l a r to 1 , 2 - D C P , i s n o t l i k e l y to be found w i t h 1,2-DCP i n a i r samples a n d , t h e r e f o r e , s h o u l d seldom cause a problem (11, 1 2 ) . The o t h e r p o t e n t i a l i n t e r f è r e n t , 1,2-dichloroethane, i s an i m p u r i t y i n r e a g e n t - g r a d e 1,2-DCP but t y p i c a l l y r e p r e s e n t s l e s s t h a n 1% (w/w) o f t h e r e a g e n t ( 1 3 ) . Thus, t h i s compound s h o u l d n o t o r d i n a r i l y p o s e a n i n t e r f e r e n c e p r o b l e m . ( W i t h a Carbowax 20M g l a s s c a p i l l a r y c o l u m n (30 m b y 0 . 2 5 mm i . d . ) i n p l a c e o f a c o n v e n t i o n a l p a c k e d c o l u m n , 1 , 2 - D C P was r e s o l v e d from 1,2-dichloroethane.) The GC r e s p o n s e was c a l i b r a t e d f o r e a c h a n a l y t e t o d e t e r m i n e the r e p r o d u c i b i l i t y o f i n j e c t i o n s , t h e d e t e c t i o n l i m i t , and t h e working range o f the method. B o t h peak h e i g h t and peak a r e a response

measurements

were

taken.

F o r HCCP t h e c h r o m a t o g r a p h i c

response

was f o u n d

to be a

l i n e a r a n d r e p r o d u c i b l e f u n c t i o n o f HCCP c o n c e n t r a t i o n i n t h e r a n g e o f a b o u t 5 . 0 t o 142 ng/mL (25 t o 710 pg i n j e c t e d ) w i t h a c o r r e l a t i o n c o e f f i c i e n t of 0.9993 f o r peak h e i g h t measurement. l i n e a r r e s p o n s e was o n l y o b t a i n e d , h o w e v e r , i f t h e c o l u m n was conditioned d a i l y with several 5-yL i n j e c t i o n s of a r e l a t i v e l y

A

c o n c e n t r a t e d s o l u t i o n o f HCCP i n h e x a n e . T h e d e t e c t i o n l i m i t was a b o u t 5 ng/mL (25 p g i n j e c t e d ) . At t h i s l i m i t , the p r e c i s i o n of peak h e i g h t measurements c o r r e s p o n d e d to a r e l a t i v e s t a n d a r d d e v i a t i o n (RSD) o f 6% w i t h a r a t i o o f a b o u t 7 : 1 f o r p e a k h e i g h t to background n o i s e . T h e RSD f o r p e a k a r e a m e a s u r e m e n t s w i t h a m e c h a n i c a l i n t e g r a t o r was a b o u t 33%, c o r r e s p o n d i n g t o a much lower p r e c i s i o n t h a n t h a t o b t a i n e d w i t h peak h e i g h t measurements.


Choudhary; Chemical Hazards in the Workplace ACS Symposium Series; American Chemical Society: Washington, DC, 1981. tetrachloroethylene hexachloroethane 1,2,4-trichlorobenzene HCCP 4-chlorobiphenyl

Hexachloroethane

1,2,4-Trichlorobenzene

HCBD

Octachlorocyclopentene

HCBD

Tetrachloroethylene

HCCP

and

cis-

tetrachloro-1,2difluoroethane

1,2-dichloroethane

dibromomethane

tetrachloroethylene

trichloroethylene

1,3-dichloro-l-propene

trans-

2,2-dichloropropane

1,3-dichloropropane

1,2-DCP

Table I. Compounds S e l e c t e d f o r I n t e r f e r e n c e T e s t i n g i n the Development o f A n a l y t i c a l P r o c e d u r e s f o r the Three C h l o r o c a r b o n s



b.

a.

f o r compoundb

parameters

95% A r , 20 m L / m i n

hexane

d e t e c t o r p u r g e , 5% CHi+, 95% A r , 80 m L / m i n

150 ° C 135 ° C 250 °C

h 9

5% CR

capture

HCBD

con-

2

15% ( v / v ) a c e t o n e i n cyclohexane

2

hexane

3

mL/min

furnace temperature, 850 ° C ; e l e c t r o l y t e , 50% ( C H ) C H 0 H i n H 0 , 0.9 mL/min; H 2 , 50 m L / m i n

, 25

d e t e c t o r p u r g e , 5% CHi+, 95% A r , 80 m L / m i n

2

150 ° C 50 ° C

N

3% Carbowax 1500 o n C h r o m o s o r b W HP (60/80 mesh) i n n i c k e l (2 mm i . d . b y 3 m)

Hall electrolytic ductivity

240 °C 135 ° C 250 ° C

5% C H i , , 95% A r , 20 m L / m i n

a

1,2-DCP

f o r Each of the C h l o r o c a r b o n s

3% 0 V - 1 o n G a s - C h r o m Q (100/120 mesh) i n g l a s s (4 mm i . d . b y 2 m)

electron

Procedure

T h e i n j e c t i o n v o l u m e was 5 y L o f s a m p l e a n d 1 y L o f s o l v e n t

was u s e d f o r t h e 1 , 2 - D C P m e t h o d . flush.

A H e w l e t t - P a c k a r d 5750A GC was u s e d f o r t h e HCCP a n d HCBD m e t h o d s a n d a P e r k i n - E l m e r S i g m a 2 GC

Solvent

Detector

Temperatures Injection port Column Detector

Carrier

gas

3% 0 V - 1 o n G a s - C h r o m Q (100/120 mesh) i n g l a s s (4 mm i . d . b y 2 m)

Column

Operating

electron

capture

HCCP

O p t i m i z e d GC A n a l y t i c a l

Detector

conditions

Table I I .


54

C H E M I C A L HAZARDS IN T H E W O R K P L A C E Detector

detection The and

s e n s i t i v i t y was b e t t e r

limit

response, peak a r e a

was 0 . 8

ng/mL

f o r HCBD t h a n f o r H C C P .

(4 p g i n j e c t e d )

The

w i t h a n RSD o f 10%.

h o w e v e r , t o HCCP was n o n l i n e a r f o r b o t h p e a k h e i g h t measurements i n t h e w o r k i n g range o f 0 . 8 t o about

170 ng/mL (850 p g i n j e c t e d ) . (A s l i g h t c u r v a t u r e i n r e s p o n s e v e r s u s c o n c e n t r a t i o n s u c h a s t h a t o b s e r v e d i s n o t uncommon f o r the

response

o f a n ECD ( 1 4 ) . )

m e a s u r e m e n t s w e r e more p r e c i s e mechanical integrator. range

For 1 , 2 - D C P , the H a l l o f 6 . 9 3 t o 347 yg/mL

F o r HCBD a s f o r H C C P , than peak a r e a


with

a

d e t e c t o r r e s p o n s e was l i n e a r i n t h e ( 3 4 . 7 t o 1735 n g i n j e c t e d ) . A p l o t of

peak a r e a v e r s u s c o n c e n t r a t i o n i n t h i s t h e P e r k i n - E l m e r Sigma 10 D a t a System) c o e f f i c i e n t (r) of 1.0000.

HCCP,

peak h e i g h t

measurements

range (as d e t e r m i n e d w i t h yielded a correlation

S e l e c t i o n of C o l l e c t i o n Media. The methods d e v e l o p e d f o r HCBD, a n d 1 , 2 - D C P i n v o l v e t h e c o l l e c t i o n o f t h e a n a l y t e s

from a i r on s o l i d sorbent m a t e r i a l s i n s m a l l Pyrex t u b e s . Each t u b e i s 7 cm l o n g b y 6 mm o . d . a n d 4 mm i . d . T h e recommended samp l i n g t u b e s c o n t a i n two b e d s o f s o r b e n t m a t e r i a l — o n e l a y e r f o r s o r p t i o n and a s e c o n d , s m a l l e r , backup l a y e r to m o n i t o r b r e a k through i f the c a p a c i t y of the s o r b i n g l a y e r i s exceeded. A sampling tube of t h i s type o f f e r s s e v e r a l advantages f o r personal monitoring. The p o r t a b i l i t y o f t h e d e v i c e a l l o w s i t to be u s e d f o r s a m p l i n g t h e b r e a t h i n g a i r o f a n i n d i v i d u a l . Thus, the exposure o f an i n d i v i d u a l worker to a chemical substance can be a s c e r t a i n e d . Many p r e v i o u s l y a v a i l a b l e s a m p l i n g m e t h o d s required the use of bubblers with l i q u i d absorbers or other bulky and c o m p l i c a t e d a p p a r a t u s t h a t was i n c o n v e n i e n t f o r p e r s o n a l m o n i toring. The sorbent tube i s n o t o n l y v e r y c o n v e n i e n t to u s e ; i t s compactness

i s convenient f o r shipping

and h a n d l i n g .

The m a t e r i a l s c o n s i d e r e d a s s o r b e n t s f o r H C C P , HCBD, a n d 1 , 2 - D C P w e r e s u b j e c t e d t o two t y p e s o f p r e l i m i n a r y t e s t s — c a p a c i t y t e s t s and d e s o r p t i o n e f f i c i e n c y t e s t s . On t h e b a s i s o f t h e s e t e s t s , a s o r b e n t m a t e r i a l was t e n t a t i v e l y a n a l y t e ; t h e s e l e c t i o n was c o n f i r m e d o n l y a f t e r pling

s e l e c t e d f o r each t h e o v e r a l l sam-

a n d a n a l y s i s method was v a l i d a t e d . The

sorbent materials

evaluated

f o r each a n a l y t e

are l i s t e d

in Table I I I . ( I t was n e c e s s a r y t o c l e a n some o f t h e s o r b e n t m a t e r i a l s t o remove i m p u r i t i e s p r i o r t o u s e . The c l e a n i n g p r o c e dure c o n s i s t e d o f S o x h l e t e x t r a c t i o n w i t h an 80:20 m i x t u r e o f a c e t o n e and m e t h a n o l f o r 4 h f o l l o w e d for 4 h.)

by e x t r a c t i o n

with

hexane

To b e a n a c c e p t a b l e s u b s t i t u t e f o r w e t c o l l e c t o r s a n d t o s a t i s f y t h e NIOSH c r i t e r i o n f o r a c c e p t a b l e m e t h o d s , a s o r b e n t m a t e r i a l must h a v e a d e m o n s t r a t e d s o r p t i o n c a p a c i t y f o r t h e a n a l y t e t h a t i s adequate f o r sampling a r e a s o n a b l e volume o f workp l a c e a i r a t an e s t a b l i s h e d r a t e . T y p i c a l l y , a sample volume o f a t l e a s t 12 L (1 h a t 0 . 2 L / m i n ) i s d e s i r a b l e . I n t h e c a p a c i t y t e s t s , t h e s o r b e n t m a t e r i a l s were c h a l l e n g e d


4.

BOYD E T A L .

Organochlorine

Table

III.

55

Sorbent M a t e r i a l s Evaluated for


Compounds

Each A n a l y t e 1,2-DCP

HCCP

HCBD

A m b e r l i t e XAD-2 (20/50 mesh)b

Tenax-GC (35/60 m e s h )

Porapak R (50/80 mesh)c

A m b e r l i t e XAD-2 (20/50

Ambersorb XE-340 (20/50 m e s h ) c

a

c

mesh)b

coconut c h a r c o a l (20/40 mesh) (SKC C a t . N o . 2 2 6 - 0 1 - 0 1 ) petroleum

petroleum charcoal (20/40 mesh) (SKC

Chromosorb (60/80

Tenax-GC (35/60 Porapak Τ (80/100

104

mesh)

mesh)

c

c

mesh)c

Porapak Τ (50/80 m e s h ) c

charcoal

(20/40 mesh) (SKC C a t . N o . 2 2 6 - 3 6 - 0 1 )

C a t . N o . 226-38-01)

petroleum charcoal (20/40 m e s h ) (Barnebey-Cheney Type c

580-26)

Carbosieve Β (45/60 mesh)c silica gel (60/80 m e s h ) c Amberlite (16/50

XAD-4 mesh)

Porapak R (50/80 m e s h )

c

c

O n l y two s o r b e n t m a t e r i a l s w e r e e v a l u a t e d f o r t h e HCBD method b e c a u s e b o t h p e r f o r m e d s a t i s f a c t o r i l y a n d i t was c o n s i d e r e d unnecessary to evaluate other m a t e r i a l s . P r e c l e a n e d by t h e s u p p l i e r , A p p l i e d c.

Soxhlet

extracted with

Sciences,

acetone/methanol

Inc.

mixture

and hexane.


56


with laboratory the c a p a c i t y of i n a Pyrex observed.

t e s t atmospheres of the a p p r o p r i a t e a n a l y t e u n t i l e i t h e r a 5 0 - o r 100-mg q u a n t i t y o f e a c h m a t e r i a l

t u b e was e x c e e d e d and a n a l y t e b r e a k t h r o u g h was ( I n f i e l d a p p l i c a t i o n s , t h e recommended s a m p l i n g

w o u l d c o n t a i n two s e c t i o n s single of

tube—the

of

sorbent m a t e r i a l

sorbing section

packed i n t o

and a s m a l l e r b a c k u p

device a

section.)

The c a p a c i t y t e s t s r e q u i r e d t h e c o n s t r u c t i o n and e v a l u a t i o n a v a p o r g e n e r a t o r , a s a m p l i n g s y s t e m , and a g e n e r a t o r m o n i t o r


for each a n a l y t e . The system used f o r 1,2-DCP i s d e p i c t e d i n the figure. S i m i l a r s y s t e m s w e r e c o n s t r u c t e d f o r HCCP and HCBD e x c e p t b u b b l e r measurements were used t o m o n i t o r the g e n e r a t o r e f f l u e n t f o r t h e s e compounds w h e r e a s a t o t a l h y d r o c a r b o n a n a l y z e r was u s e d to m o n i t o r the 1 , 2 - D C P e f f l u e n t . The s y s t e m s o p e r a t e d o n t h e vapor s a t u r a t i o n technique w i t h the a n a l y t e c o n c e n t r a t i o n c o n t r o l l e d by t h e l o w t e m p e r a t u r e c o o l e r and t h e d i l u t i o n v o l u m e . A m i d g e t i m p i n g e r was e m p l o y e d a s a r e s e r v o i r f o r e a c h a n a l y t e w i t h b o t h t h e t e m p e r a t u r e o f t h e i m p i n g e r and t h e f l o w o f n i t r o g e n through the r e s e r v o i r c l o s e l y r e g u l a t e d . The n i t r o g e n l a d e n w i t h t h e a p p r o p r i a t e a n a l y t e was m i x e d w i t h p r e c l e a n e d d i l u t i o n a i r i n a g l a s s s p l a s h t r a p — t h e m i x i n g c h a m b e r — a n d was p a s s e d i n t o a c y l i n d r i c a l g l a s s s a m p l i n g chamber w i t h s e v e n s a m p l i n g p o r t s f o r s o r b e n t tubes and o t h e r s a m p l i n g d e v i c e s . The e x c e s s g e n e r a t o r e f f l u e n t was v e n t e d t h r o u g h a b e d o f c h a r c o a l and t h e n i n t o a hood. To p r o v i d e c l e a n , d r y a i r f o r t h e g e n e r a t o r , t h e a i r s t r e a m ( t a k e n f r o m a l a b o r a t o r y a i r s u p p l y s y s t e m ) was p a s s e d s e q u e n t i a l l y t h r o u g h a b e d o f c h a r c o a l , a f e l t f i l t e r , and f i n a l l y t h r o u g h a membrane f i l t e r w i t h a n a v e r a g e p o r e d i a m e t e r o f 0 . 2 y m . The d i l u t i o n a i r was h u m i d i f i e d by m e t e r i n g p a r t o f t h e a i r s t r e a m through a heated Greenburg-Smith impinger c o n t a i n i n g deionized water. To d e t e r m i n e

the

capacity

of

distilled,

a sorbent m a t e r i a l ,

generator

e f f l u e n t was s a m p l e d i n t o s o r b e n t t u b e s a t a known r a t e a n d b r e a k t h r o u g h f r o m t h e t u b e s was m o n i t o r e d . I n some d e s o r p t i o n e f f i c i e n c y t e s t s , t h e s o r b e n t m a t e r i a l s t h a t h a d y i e l d e d t h e most p r o m i s i n g r e s u l t s i n t h e c a p a c i t y t e s t s w e r e s p i k e d w i t h s o l u t i o n s o f HCCP i n h e x a n e , HCBD i n h e x a n e , o r 1 , 2 - D C P i n 15% ( v / v ) a c e t o n e i n c y c l o h e x a n e . d e s o r p t i o n e f f i c i e n c y was d e t e r m i n e d p r i o r t o The

spiking

procedure

for

all

In other capacity

t e s t s was a s

tests, tests.

follows:

•

F i f t y o r one hundred m i l l i g r a m s o f to a g l a s s v i a l .

•

F i v e o r t e n m i c r o l i t e r s o f h e x a n e c o n t a i n i n g a known amount o f t h e a n a l y t e was i n j e c t e d i n t o t h e s o r b e n t bed i n t h e v i a l . T h i s amount o f s o l v e n t e v a p o r a t e d rapidly.

•

The v i a l

was

sealed

and s t o r e d

s o r b e n t was a d d e d

overnight.



FILTERED AIR OR NITROGEN

Figure 1.

LOW-TEMPERATURE C O O L E R A N D 1,2-DCP,

VALVE ^

(jjj)

Schematic of vapor generator and sampling system for 1,2-DCP

ψ

GC SAMPLING PORT.

SEPTUM (SYRINGE INJECTION A N D SAMPLING P O R T K

MIXING CHAMBER

THERMOMETER


TOTAL HYDROCARBON ANALYZER

CHARCOAL TRAP AND VENT

SORBENT TUBE (7 T U B E S A M P L I N G PORTS LOCATED AROUND BOTTOM OF CHAMBER)

ο

Î3-

ri

§

r

Η >

w

Ο

W Ο

58

CHEMICAL

•

One o r

•

The v i a l was c a p p e d a n d e x t r a c t e d bath for a s p e c i f i e d time.

•

T h e s a m p l e e x t r a c t was

HAZARDS

IN T H E

two m i l l i l i t e r s o f h e x a n e was added t o i n an

WORKPLACE

the

vial.

ultrasonic

analyzed.


A s e r i e s o f e x p e r i m e n t s was a l s o p e r f o r m e d t o d e t e r m i n e t h e s a m p l e b l a n k and t h e optimum e x t r a c t i o n t i m e . When r e q u i r e d , s e v e r a l s o l v e n t s were e v a l u a t e d t o o b t a i n o p t i m a l e x t r a c t i o n efficiencies. A d e s o r p t i o n e f f i c i e n c y o f a t l e a s t 0 . 8 was r e q u i r e d . The s o r b e n t m a t e r i a l s t h a t p e r f o r m e d b e s t i n t h e c a p a c i t y and d e s o r p t i o n e f f i c i e n c y t e s t s were i n v e s t i g a t e d f u r t h e r w i t h r e s p e c t to the s t a b i l i t y of the sorbed a n a l y t e . Preliminary tests o f a n a l y t e s t a b i l i t y were c o n d u c t e d by a p r o c e d u r e s i m i l a r t o t h a t i n the d e s o r p t i o n e f f i c i e n c y t e s t s ; the procedure d i f f e r e d i n t h a t s a m p l e s were s t o r e d 7 d p r i o r t o a n a l y s i s r a t h e r t h a n I d . To be a c c e p t a b l e , a s o r b e n t m a t e r i a l had t o e x h i b i t no s t a t i s t i c a l l y s i g n i f i c a n t l o s s o f a n a l y t e a t the 0.05 s i g n i f i c a n c e l e v e l by a t w o - t a i l e d t_ t e s t . W i t h the p r e l i m i n a r y e v a l u a t i o n o f the sorbent m a t e r i a l s c o m p l e t e d , a s o r b e n t m a t e r i a l was s e l e c t e d f o r e a c h method o n t h e b a s i s o f t h e most s a t i s f a c t o r y o v e r a l l p e r f o r m a n c e . In a d d i t i o n , a s o l v e n t o r s o l v e n t m i x t u r e was a l s o s e l e c t e d f o r e a c h m e t h o d . The s e l e c t i o n s a r e p r e s e n t e d i n T a b l e IV a l o n g w i t h t h e b r e a k t h r o u g h t i m e s , b r e a k t h r o u g h v o l u m e s , b r e a k t h r o u g h c a p a c i t i e s , and d e s o r p t i o n e f f i c i e n c i e s under the s p e c i f i e d sampling c o n d i t i o n s . Method

Validation

The p u r p o s e o f t h i s p o r t i o n o f t h e r e s e a r c h was t o v a l i d a t e t h e d e v e l o p e d methods by g e n e r a t i n g e n o u g h d a t a f o r a s t a t i s t i c a l evaluation. The v a l i d a t i o n t e s t s were c o n d u c t e d a c c o r d i n g to NIOSH g u i d e l i n e s (9). I n i t i a l l y , t e s t s were p e r f o r m e d t o d e t e r m i n e t h e LAQL f o r each a n a l y t e . The l o n g - t e r m s t a b i l i t y o f each s o r b e d a n a l y t e a t i t s LAQL was a l s o d e t e r m i n e d . F i n a l l y , t h e a c c u r a c y and p r e c i s i o n o f t h e a n a l y t i c a l method a l o n e a n d a l s o t h e o v e r a l l a c c u r a c y and p r e c i s i o n o f t h e c o m b i n e d s a m p l i n g and a n a l y t i c a l methods were determined. A l l t e s t s were p e r f o r m e d w i t h the p r e v i o u s l y d e v e l oped a n a l y t i c a l p r o c e d u r e s and s a m p l i n g d e v i c e s . D e t e r m i n a t i o n of LAQL. T e s t s were p e r f o r m e d w i t h t h e r e c o m mended a n a l y t i c a l p r o c e d u r e s a n d s o r b e n t m a t e r i a l s t o e s t a b l i s h t h e LAQL f o r e a c h a n a l y t e . A s s t a t e d p r e v i o u s l y , t h e LAQL i s t h e s m a l l e s t amount o f a compound t h a t c a n be d e t e r m i n e d w i t h a r e c o v e r y f r o m t h e s o r b e n t g r e a t e r t h a n 80% and a r e l a t i v e s t a n d a r d d e v i a t i o n l e s s t h a n 10% (9). The p r o c e d u r e f o r t h e s e t e s t s was s i m i l a r t o t h a t d e s c r i b e d f o r the d e s o r p t i o n e f f i c i e n c y t e s t s . The s p i k e d s a m p l e s w e r e s t o r e d o v e r n i g h t a n d e x t r a c t e d , and t h e e x t r a c t s were a n a l y z e d .


Choudhary; Chemical Hazards in the Workplace ACS Symposium Series; American Chemical Society: Washington, DC, 1981. 3

extraction.

3

C

c

15% ( v / v ) a c e t o n e i n cyclohexane

100 mg s o r b i n g l a y e r , 50 mg b a c k u p l a y e r

(1.04 yg)

L/min)

C a t . No. 226-36-01) (0.05

0.92

2000

4

>l c

(SKC

and tube c a p a c i t y

of

about

g l a s s wool

by a f a c t o r

Silanized

were i n c r e a s e d

The s o r b e n t t u b e s w e r e P y r e x (7 cm l o n g b y 6 mm o . d . a n d 4 mm i . d . ) , plugs separated the sections.

Breakthrough time, breakthrough volume, 4 a t a r e l a t i v e h u m i d i t y o f a b o u t 80%.

3

F o r t h e s e t e s t s t h e t e m p e r a t u r e o f t h e g e n e r a t o r e f f l u e n t was m a i n t a i n e d a t 25 t o 28 ° C a n d t h e r e l a t i v e h u m i d i t y a t g r e a t e r t h a n 80%. The c o n c e n t r a t i o n s o f the a n a l y t e s i n the g e n e r a t o r e f f l u e n t was 1 mg/m o f HCCP, 10 mg/m o f HCBD, a n d 700 mg/m o f 1 , 2 - D C P .

This material

r e q u i r e d c l e a n i n g by S o x h l e t

hexane

solvent

hexane

(4 n g )

Extraction

1.00


(27.4 ng)


0.94

L/min)

1,2-DCP petroleum charcoal (20/40 mesh)

Analytes

Sorbent tube conf i g u r a t i o n ^

Average d e s o r p t i o n e f f i c i e n c y of indicated quantity of analyte

yg

>1000

b

>100

>8 ( 0 . 2

Tube c a p a c i t y ,

L/min) >100

(0.2

HCBD

f o r the Three

A m b e r l i t e XAD-2 (20/50 mesh)

>100

>8

a

HCCP

C o l l e c t i o n Media Selected

Porapak T ( 8 0 / 1 0 0 mesh)

IV.

Breakthrough volume,b L

time,b h

material

Breakthrough

Sorbent

Table



60

about

The LAQL was a b o u t 25 400 ng f o r 1 , 2 - D C P . Determination of

ng f o r

stored

for

at

about

Long-Term S t a b i l i t y of

T e s t s were p e r f o r m e d to d e t e r m i n e i n t u b e s t h a t had b e e n e x p o s e d t o then

HCCP,

least

7 d.

20 n g f o r

HCBD,

and

Sorbed A n a l y t e .

the s t a b i l i t y of sorbed a n a l y t e s g e n e r a t o r e f f l u e n t and t h a t w e r e

For

each method,

the

analyte

con-

c e n t r a t i o n i n t h e g e n e r a t o r e f f l u e n t was m a i n t a i n e d a t a b o u t 0 . 3 X LAQL p e r l i t e r ; 3 L o f t h e g e n e r a t o r a t m o s p h e r e was s a m p l e d


at a r a t e of 0.2 L/min to y i e l d F o l l o w i n g e x p o s u r e , the s o r b e n t and p l a s t i c c a p s f o r s t o r a g e .

a tube l o a d i n g of tubes were s e a l e d

about the LAQL. w i t h T e f l o n tape

The r e s u l t s a s s u m m a r i z e d i n T a b l e V i n d i c a t e d t h a t t h e s t a b i l i t y was s a t i s f a c t o r y f o r a l l t h r e e m e t h o d s . To be acceptable, t h e a v e r a g e r e c o v e r y o f e a c h a n a l y t e h a d t o be a t l e a s t 80%, and t h e d i f f e r e n c e b e t w e e n t h e a v e r a g e r e c o v e r y o n t h e f i r s t d a y and t h e a v e r a g e r e c o v e r y a f t e r s t o r a g e ( f o r a t l e a s t 7 d) had t o be s t a t i s t i c a l l y i n s i g n i f i c a n t a t t h e 0 . 0 5 s i g n i f i c a n c e l e v e l by a t w o - t a i l e d t_ t e s t (9) . Table V.

Long-Term S t a b i l i t y of

Sorbed A n a l y t e s ^

HCCP Average after

concentration 0 d , b , c yg/m

Storage p e r i o d , Average after age

9.93

0

d

9.04

28

yg/m

9.47

± 0.28

critical

34

± 0.37

8.93

± 0.31

118

±

1.11

2.18

2.12

2.26

b.

Samples were e x t r a c t e d exposure.

c.

N i n e t y - f i v e percent data.

confidence

limits

are

In

some m i g r a t i o n o f

the

t h e HCCP m e t h o d , to

4

7

0.72

Each v a l u e r e p r e s e n t s value for 1,2-DCP; i t

section

±

0.67

a.

sorbing

121

5

3

_t t

± 0.27

1,2-DCP

3

concentration indicated stor-

period,

HCBD

the

a t l e a s t s i x samples represents only f i v e and a n a l y z e d

backup

section

except the samples.

immediately

occurred

0-d

after

given for

these

compound f r o m

the

during storage.


To

4.

BOYD E T A L .

minimize field, rated

this

it

Organochlorine

to

that

t h e two s o r b e n t

average recovery the

f o r these

analyte

to be e x p e c t e d . t e s t s were

the analyte

X LAQL,

sepa-

similar

levels

f o r each

quantities

to e s t a b l i s h

the

The s p i k i n g

and a n a l y s i s

proce-

to those d e s c r i b e d

preliminary desorption efficiency

1,2-DCP, 10

be

and P r e c i s i o n o f t h e A n a l y t i c a l

T h e d e s o r p t i o n e f f i c i e n c y was d e t e r m i n e d

method a t w i d e l y s e p a r a t e d dures

i n the

sections

storage.

Determination of Accuracy Procedure.

61

p r o b l e m i n t h e a p p l i c a t i o n o f t h e method

i s recommended

prior

Compounds

tests.

earlier

c h o s e n were

approximately

F o r HCBD,

o n l y two l e v e l s

a n d 1000 X L A Q L .

for

F o r HCCP a n d the LAQL, were

t e s t e d — t h e LAQL a n d 1000 X L A Q L . The


1.004 the

experiments

f o r HCCP,

gave a v e r a g e d e s o r p t i o n e f f i c i e n c i e s

0.984

f o r HCBD,

p r e c i s i o n was f o u n d

each the

of the three RSD w e r e

(90.

t o b e homogeneous

analytes

at

the l e v e l s

of

for 1,2-DCP.

Because

by B a r t l e t t s

test for

f

tested,

the values

of

p o o l e d t o o b t a i n a n o v e r a l l RSD f o r e a c h compound

The p o o l e d v a l u e s

3.1%

and 0.954

were

3.0% f o r H C C P ,

1.1% f o r HCBD, a n d

f o r 1,2-DCP. D e t e r m i n a t i o n o f A c c u r a c y and P r e c i s i o n o f t h e O v e r a l l

pling

and A n a l y t i c a l P r o c e d u r e .

The f i n a l

e a c h method was t h e d e t e r m i n a t i o n the

tubes were

at

a relative

to

28 ° C .

of

about

the

exposed

to t e s t

results

g a s was s a m p l e d i n t o

by an independent p r o c e d u r e ,

simultaneously with sorbent analyzer tubes The

f o r 1,2-DCP. transferred

c o n t e n t s were

tests:

Also,

procedures The about

exposure,

the r e s u l t s

b y more

o f 25

L/min,

and a

tube.

To

the t e s t

total

evaluate

g a s was s a m p l e d

with bubblers

with a total the sorbent

containing

hydrocarbon sections

wool plugs

i n the

to v i a l s .

appropriate

analyzed. of the r e s u l t s

were

w i t h 10% r e l a t i v e

c o u l d n o t be b i a s e d

HCCP method was e v a l u a t e d 3

as noted standard

above devia-

from the independent

i n the concentration

i n 3-L a i r samples.

the

independent a n a l y t i c a l

a n d t h e p o o l e d RSD was 8%.

procedure

range

The average b i a s

( b u b b l e r measurements)

of

from was

(This estimate of p r e c i s i o n

a n assumed RSD o f 5% f o r t h e p r e c i s i o n o f a i r m e t e r i n g

with a personal

s a m p l i n g pump.

The a i r s a m p l i n g i n t h e s e

t e s t s was p e r f o r m e d w i t h c r i t i c a l

variation

flow o r i f i c e s

i n a i r s a m p l i n g r a t e s was e x p e r i e n c e d .

t i o n was c o n s i d e r e d n e c e s s a r y in

each

sorin air

than ±10% ( 9 ) .

+1%

tory

and a t e m p e r a t u r e

e x t r a c t e d w i t h 1 mL o f t h e

80% r e c o v e r y

13 t o 873 y g / m

includes

a n d (1)

tests,

of the analytes

along with the glass

minimum r e q u i r e m e n t s

other

tion.

then

After

and t h e e x t r a c t s were

The for

tubes

0 °C f o r HCCP o r HCBD or. (2)

were

solvent,

atmospheres

h u m i d i t y o f 80% o r g r e a t e r

and p r e c i s i o n o f

In these

T h e s a m p l i n g r a t e was n o m i n a l l y 0 . 2

3 L of test

hexane a t

steps.

Sam-

i n completion of

of the accuracy

combined s a m p l i n g and a n a l y t i c a l

bent

step

sampling rates

in field

where

Thus,

to i n c l u d e the v a r i a t i o n s

a

laboralittle correc-

expected

measurements.)



62 The

HCBD method was e v a l u a t e d

i n the concentration

range of

a b o u t 10 t o 2000 y g / m i n 3-L a i r samples. The average b i a s from t h e i n d e p e n d e n t a n a l y t i c a l method ( b u b b l e r m e a s u r e m e n t s ) was -7% 3

and

the pooled r e l a t i v e

relative

standard

d e v i a t i o n was 9%.

The method f o r 1 , 2 - D C P was e v a l u a t e d i n t h e c o n c e n t r a t i o n r a n g e o f 0 . 1 2 4 t o 128 mg/m i n 3-L a i r samples. The a v e r a g e b i a s 3

from the independent a n a l y t i c a l procedure ( t o t a l hydrocarbon a n a l y z e r ) was l e s s t h a n 1% o v e r t h e r a n g e o f t h e m e t h o d . The p o o l e d r e l a t i v e s t a n d a r d d e v i a t i o n was 6.4% o v e r t h i s r a n g e . A summary o f t h e r e s u l t s Table V I .

in


Table V I .

o f t h e method v a l i d a t i o n s

Summary o f R e s u l t s

f o r Method V a l i d a t i o n s

HCCP LAQL,

ng

25

Desorption e f f i c i e n c y

Range o f v a l i d a t i o n i n 3-L a i r sample,b yg/m

13 t o 865

p o o l e d RSD, %

The d e s o r p t i o n from near

b.

1,2-DCP 400

0.984

0.954

10 t o 2 , 0 0 0

124 t o

128,000

3

Overall

a.

HCBD 20

1.004

a

appears

8.0

9.0

e f f i c i e n c y was a v e r a g e d

6.4

for levels

ranging

t h e LAQL t o 1000 X L A Q L .

Data obtained p o o l e d RSD.

i n this

r a n g e were used

to c a l c u l a t e

the

A p p l i c a t i o n o f Methods M e t h o d s f o r a l l t h r e e compounds h a v e b e e n a p p r o v e d b y NIOSH. The m e t h o d s f o r HCCP a n d HCBD w e r e p u b l i s h e d i n t h e "NIOSH M a n u a l of A n a l y t i c a l Methods , V o l . 5 (15). T h e method f o r 1 , 2 - D C P be i n c l u d e d i n V o l u m e 6 o f t h e M a n u a l t o b e p u b l i s h e d s o o n . 1 1

the air

will

The m e t h o d f o r HCCP h a s b e e n u s e d r o u t i n e l y b y i n d u s t r y o v e r p a s t y e a r t o d e t e r m i n e e m p l o y e e e x p o s u r e s t o t h e compound i n (16). T h e method h a s b e e n r e p o r t e d t o b e r e l i a b l e . Its

a p p l i c a t i o n has a l s o f a c i l i t a t e d p l a n n i n g f o r e n g i n e e r i n g c o n trols. P l a n s a r e underway t o e m p l o y t h e method d e v e l o p e d f o r HCCP i n p e r s o n a l m o n i t o r i n g a n d p e r i m e t e r s a m p l i n g d u r i n g t h e cleanup o f waste d i s p o s a l s i t e s (17, 1 8 ) . In t h i s endeavor, the method w i l l a l s o b e e m p l o y e d t o d e t e r m i n e o t h e r v o l a t i l e c h l o r i n a t e d compounds t h a t a r e l i k e l y t o be p r e s e n t i n c l u d i n g t e t r a chloroethylene, t r i c h l o r o e t h y l e n e , hexachlorobenzene, hexachloroe t h a n e , a n d HCBD.



4.

BOYD ET AL.

Organochlorine Compounds

63

Acknowledgments Ms. Debra Y. Harton, Assistant Chemist, assisted in the laboratory work. Overall supervision of the project was the responsibility of Dr. William J. Barrett, Director, Applied Sciences Research, and Dr. Herbert C. Miller, Head, Analytical and Physical Chemistry Division. Other personnel of Southern Research Institute provided valuable advice. These include Ms. Ruby H. James, Head, Environmental Analytical Chemistry Section; Dr. Thomas P. Johnston, Head, Pharmaceutical Chemistry Division; and Dr. Edward B. Dismukes, Senior Research Adviser. This work was conducted under contract with NIOSH (210-78-0012); Dr. Robert H. H i l l , Jr., Project Officer, Mr. Robert A. Glaser, Project Officer, and Dr. Alexander W. Teass, Head, Organic Methods Section of the Measurements Research Branch, provided effective guidance and encouragement. Literature Cited 1. Taylor, D. G. "NIOSH Manual of Analytical Methods", Vol. 1, National Institute for Occupational Safety and Health, Cincinnati, OH, 1979, p v. 2.

Taylor, D. G.; Kupel, R. E.; Bryant, J. M. "Documentation of the NIOSH Validation Tests", National Institute for Occupational Safety and Health, Cincinnati, OH, 1977.

3.

Mackison, F. W.; Stricoff, R. S.; Partridge, L. J. "Pocket Guide to Chemical Hazards", National Institute for Occupational Safety and Health, Cincinnati, OH, 1978; pp 1-3.

4.

"Development of Air Sampling and Analytical Methods for Toxic Chlorinated Organic Compounds—Research Report for Hexachlorocyclopentadiene", Southern Research Institute, Birmingham, AL, NIOSH Contract No. 210-78-0012, National Institute for Occupational Safety and Health, Cincinnati, OH, 1980.

5.

"Development of Air Sampling and Analytical Methods for Toxic Chlorinated Organic Compounds—Research Report for Hexachlorobutadiene", Southern Research Institute, Birmingham, AL, NIOSH Contract No. 210-78-0012, National Institute for Occupational Safety and Health, Cincinnati, OH, 1980.

6.

"Development of Air Sampling and Analytical Methods for Toxic Chlorinated Organic Compounds—Research Report for 1,2-Dichloropropane", Southern Research Institute, Birmingham, AL, NIOSH Contract No. 210-78-0012, National Institute for Occupational Safety and Health, Cincinnati, OH, 1980.


64

CHEMICAL HAZARDS IN THE WORKPLACE

7.

"Threshold Limit Values of Airborne Contaminants", Federal Register, 1979, 44, 8855.

8.

Kelley, W. D. National Safety News, October 1979, 83.

9.

"Development of Air Sampling and Analytical Methods for Toxic Chlorinated Organic Compounds", Southern Research Institute, Birmingham, AL, NIOSH Contract No. 210-78-0012, National Institute for Occupational Safety and Health, Cincinnati, OH, 1978.


10. Krejci, M.; Dressier, M. Chromatog. Rev., 1970, 13, 1-59. 11. McBee, E. T.; Haas, H. B.; Chao, T. H.; Welch, Z. D.; Thomas, L. E. Ind. Eng. Chem., 1941, 33, 176. 12. Standen, A. "Kirk-Othmer Encyclopedia of Chemical Technology", Vol. 9, Interscience:New York, 1966, pp 743-750. 13. Aldrich Chemical Company, personal communication, 1980. 14. Lillian, D.; Bir Singh, H. Anal. Chem., 1974, 46, 1060-3. 15. Taylor, D. G. "NIOSH Manual of Analytical Methods", Vol. 5, National Institute for Occupational Safety and Health, Cincinnati, OH, 1979, Methods Nos. 307 and 308. 16. Nagle, G. Velsicol Chemical Corporation, personal communication, 1980. 17. D'Appolonia, K. D'Appolonia Consulting Engineers, Inc., personal communication, 1980. 18. Eimutis, E. Monsanto Research Corporation, personal communication, 1980. RECEIVED September

19, 1980.


Development of Personal Sampling and Analytical Methods for

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