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Chemical Hazards in the Workplace Downloaded from pubs.acs.org by HONG KONG UNIV SCIENCE TECHLGY on 09/16/18. For personal use only.
Sampling and Breakthrough Studies with Plictran CLIFFORD C. HOUK Department of Chemistry, Ohio University, Athens, OH 45701 HARRY J. BEAULIEU 110 Veterinary Science Building, Colorado State University, Fort Collins, CO 80523 Organotin compounds are used i n three major types o f applications: biocides, catalysts and s t a b i l i z e r s in polymers (1). As stabilizers, p a r t i c u l a r l y dialkyltin compounds, they prevent degradation of halogen-containing polymers and polyamides, and nonhalogenated substances such as lubricating oils, hydrogen peroxide, polyolefins and other p l a s t i c s . The largest use o f organotin compounds i s photostabilizers i n polyvinyl chloride. Diorganotin compounds are also used as heat s t a b i l i z e r s f o r p l a s t i c s , catalysts i n the production of polyurethane foams, cold curing of silicone rubber, and corrosion inhibitors i n chlorinated heat exchange fluids (2). Triorganotin compounds are used mainly i n biocidal applications, preservatives f o r wood, t e x t i l e , paper, leather and glass, rodent repellents, molluscicides, fungicides, and insecticides. Plictran (tricyclohexyltin hydroxide), (TCHH), i s an organotin most generally used as a miticide f o r fruit trees and ornamental trees and shrubs. It was developed and is produced by Dow Chemical Company and sold as a 50% wettable powder acaracide, or 50% TCHH-50% inert diatomaceous earth. It is l i g h t tan in color and has a negligible vapor pressure (3). In general, triorganotin compounds show greater t o x i c i t y than diorganotin compounds (4). The major concern i n occupational exposure evaluations of organotin compounds, i n general, i s the potential f o r l i v e r , kidney, pulmonary, and central nervous system effects. NIOSH, in 1976 and the American Conference o f Governmental Industrial Hygienists (ACGIH), i n 1971 both recommended a threshold l i m i t value (TLV) of 0.1 mg/M f o r a l l organotin compounds (5,6). ACGIH established a TLV s p e c i f i c a l l y f o r TCHH of 5.0 mg/M , measured as t i n ) i n 1973 which was then adopted i n 1975 (7). Common usage of TCHH and other organotin compounds has caused a great deal of interest in the development of personal sampling techniques f o r organotin compounds in general. Although the vapor pressure o f TCHH i s theoretically negligible, s i g n i f i cant breakthrough o f TCHH through glass fiber f i l t e r s and o f f 3
3
0097-6156/81/0149-0109$05.00/0 © 1981 American Chemical Society
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a c t i v a t e d charcoal has been r e p o r t e d ( 8 ) . Current concensus amonq organotin r e s e a r c h e r s i s t h a t both p a r t i c u l a t e (nonvola t i l e ) and v o l a t i l e organotins can be c o l l e c t e d with high e f f i c i e n c y by impinger methods using concentrated n i t r i c a c i d ( 9 ) . Graphite furnace atomic a b s o r p t i o n spectrophotometry (AAS) has been shown t o be a v e r s a t i l e technique f o r the d e t e c t i o n o f low l e v e l s o f t i n , r e p r o d u c i b l y over a wide l i n e a r working range and was the method o f a n a l y s i s used i n t h i s study (10,11). Current methods o f c o l l e c t i n g personal samples o f o r g a n o t i n compounds produce e r r a t i c , i n c o n s i s t e n t r e s u l t s . Use o f the most e f f i c i e n t c o l l e c t i o n scheme, concentrated HNO3 i n a midget impinger, i s c e r t a i n l y unsafe. This study t e s t e d combinations o f g l a s s f i b e r , c e l l u l o s e e s t e r f i l t e r s and HN0 impingers f o r breakthrough o f P l i c t r a n . Aerosol samples o f P l i c t r a n were generated under c o n t r o l l e d l a b o r a t o r y c o n d i t i o n s . In most c a s e s , the new systems were com pared with the c o n c e n t r a t i o n s measured by HNO3 impinger c o l l e c t i o n . 3
Experimental Reagents. The chemicals used i n t h i s study were: concen t r a t e d HCl, concentrated H S(K, concentrated H N O 3 , concentrated NH^OH, 10% ν/ν H N O 3 , 3% v/v HCl, C u C l - 2 H 0 , 1000 ppm F i s h e r C e r t i f i e d AAS T i n Reference S o l u t i o n , and P l i c t r a n . Standard s o l u t i o n s o f i n o r g a n i c t i n i n 3% v/v HCl were used. S e r i a l d i l u t i o n s o f the r e f e r e n c e s o l u t i o n were made t o o b t a i n 0.01 yg/mL-1.0 yg/mL working standards. Working standards were prepared f r e s h p r i o r t o a n a l y s i s o f each s e t o f samples. 2
2
2
M a t e r i a l s . Gelman 37 mm, type A/E g l a s s f i b e r , GN-4 0.8 μ m e t r i c e l , and DM-800 0.8 μ membrane f i l t e r s were used i n t h i s study. S p e c t r a l q u a l i t y , p y r o l y t i c coated, g r a p h i t e furnaces and rods were used i n the study. The f u r n a c e c a p a c i t y was 5 μ ί o f s o l u t i o n . Manual sample i n j e c t i o n s were made with a 5 \il Eppend o r f p i p e t 4700 using d i s p o s a b l e t i p s . Sample C o l l e c t i o n . Samples were c o l l e c t e d using a 4 f o o t c u b i c chamber o f 1/4 inch plywood. A s p e c i a l pump and c a s s e t t e rack was c o n s t r u c t e d t o assure that a l l c a s s e t t e and impinger openings were a t the same l e v e l , F i g u r e 1. A l l samples were c o l l e c t e d using the c l o s e d face method. Two schemes were used to mount the f i l t e r s . One scheme used two f i l t e r s i n d i r e c t c o n t a c t , without a back-up pad, mounted i n a standard 2 p i e c e 37 mm f i e l d c a s s e t t e . The second scheme sepa r a t e d the two f i l t e r s i n a 3 piece c a s s e t t e . One f i l t e r was mounted i n the c e n t e r s e c t i o n o f the c a s s e t t e . The second f i l t e r was mounted i n the l a s t s e c t i o n both without a back-up pad. The s t a t i o n a r y sampling t r a i n c o n s i s t e d o f : a sample c a s s e t t e c o n t a i n i n g the f i l t e r s as d e s c r i b e d , a midget impinger c o n t a i n i n g 10 mL o f concentrated ΗΝΟ3 t o t r a p any breakthrough o r v o l a t i l e
8.
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Studies with
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111
components o f P l i c t r a n , which i n t u r n was f o l l o w e d by a midget impinger c o n t a i n i n g 10 mL d e i o n i z e d water t o t r a p any a c i d vapors from the preceding impinger and f i n a l l y an empty 2-piece c a s s e t t e to c o l l e c t water vapor before a i r entered the pump. Some f i l t e r s were coated with tetraamine copper(II) c h l o r i d e to determine i f a coated f i l t e r would improve the c o l l e c t i o n e f f i c i e n c y f o r TCHH. The c o a t i n g was a p p l i e d by s u c t i o n f i l t r a t i o n o f a suspension o f the complex through the f i l t e r s i n q u e s t i o n . The f i l t e r s were d r i e d i n a d e s i c c a t o r over D r i e r i t e , placed i n the c a s s e t t e s and s t o r e d u n t i l used. A e r o s o l s were drawn t o the f i l t e r s by Model G, MSA sampling pumps a t flow r a t e s o f 1.0-2.0 L/min. Pumps were pre- and post c a l i b r a t e d using standard bubble b u r e t t e methods with an i d e n t i c a l sampling t r a i n i n l i n e . Laboratory a e r o s o l s were generated with a s m a l l , 35 p s i , 750 mL c a p a c i t y home p a i n t spray d e v i c e , F i g u r e 2. A c o n c e n t r a t i o n equal t o 150 ppm P l i c t r a n o r 46.2 ppm Sn(IV), was used as t h e a e r o s o l . During each c o l l e c t i o n p e r i o d , midget impingers con t a i n i n g concentrated H N O 3 were used t o provide comparison samples s i n c e concentrated H N O 3 i s c o n s i d e r e d the most e f f i c i e n t means o f c o l l e c t i n g o r g a n o t i n compounds. Back-up impingers c o n t a i n i n g con c e n t r a t e d H N O 3 were used t o determine i f any breakthrough o f the P l i c t r a n occurred during sample c o l l e c t i o n . Sample D i g e s t i o n . F i l t e r samples were wet-ashed i n 50 mL beakers a t 120°C f o r one hour i n 6 mL o f a 2:1 mixture o f con c e n t r a t e d H N O 3 and concentrated H S0i*. A f t e r the low temperature d i g e s t i o n , the temperature was i n c r e a s e d t o 230°C f o r another hour. Two mL a l i q u o t s o f the a c i d mixture were added t o prevent evaporation t o dryness. A t the end o f the second hour the volume was reduced t o 0.5 mL o r l e s s . The remaining s o l u t i o n was quan t i t a t i v e l y t r a n s f e r r e d t o a 50 mL v o l u m e t r i c f l a s k with 3% HCl s o l u t i o n and brought t o volume. These s o l u t i o n s were s t o r e d i n n i t r i c a c i d washed Nalgene b o t t l e s u n t i l a n a l y s i s by g r a p h i t e furnace AAS. A l l impinger samples were t r e a t e d and analyzed i n the same manner. 2
Instrumentation. A V a r i a n Model 63 atomic a b s o r p t i o n spec trophotometer, equipped with a g r a p h i t e atomizer head was used t o analyze a l l samples. Instrument parameters appear i n Table I . A t i n , hollow cathode lamp was used t o generate the d e s i r e d wave l e n g t h . A deuterium arc lamp was used t o c o r r e c t f o r non-atomic absorption s i g n a l s .
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CHEMICAL
Figure 1.
Figure 2.
HAZARDS IN T H E W O R K P L A C E
Pump and cassette rack
Chamber and spray device
8.
Η ο υ κ AND B E A U L I E U
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Studies with
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113
Table I INSTRUMENT PARAMETERS (12) D - continuum, 30 ma
HCL - 286 nm, 8 ma
2
Reading mode - peak h e i g h t , s i n g l e pen r e c o r d e r with v a r i a b l e 1-10 mv input S l i t Width - 0.2 nm
Inert Gas Furnace
dry
110°C
30 s e c .
char
500°C
20 s e c .
2300°C
4 sec.
atomize
Standard Curve. The standard curve e s t a b l i s h e d during t h i s study i s shown i n F i g u r e 3. Working standard s o l u t i o n s o f 1.0 yg/mL, 0.5pg/mL, 0.1 yg/mL, 0.05yg/mL, 0.03pg/mL were prepared by s e r i a l d i l u t i o n o f l,000yg/mL c e r t i f i e d t i n r e f e r e n c e s o l u t i o n . Mean values o f r e p l i c a t e , three o r more, 5 yL i n j e c t i o n s of each c o n c e n t r a t i o n were used to e s t a b l i s h the curve by s t a n dard r e g r e s s i o n methods. Data Treatment. The experimental design o f sample c o l l e c t i o n d i d not permit s t a t i s t i c a l comparison o f the c o l l e c t i o n e f f i c i e n c i e s o f f i l t e r combinations versus concentrated H NO3 impingement. The l a b o r a t o r y chamber was designed t o simulate f i e l d c o n d i t i o n s and not provide a " c l o s e d " system i n which the c o n c e n t r a t i o n s o f P l i c t r a n c o u l d be c o n t r o l l e d . Results and D i s c u s s i o n To determine the most e f f i c i e n t combination o f f i l t e r s s e v e r a l samples with f i l t e r s i n c o n t a c t were c o l l e c t e d concurrent l y with concentrated HN0 impinger samples. The data, Table I I , suggested t h a t concentrated HN0 was a b e t t e r c o l l e c t o r o f Sn(IV) than any o f the f i l t e r combinations and t h a t uncoated g l a s s f i b e r f i l t e r s were b e t t e r c o l l e c t o r s than o t h e r f i l t e r combinations. The l a r g e breakthrough o f Sn t o the back-up impingers i n a l l cases but one was a concern. Each impinger i n t h i s case contained only 10 mL o f a c i d . With f i l t e r s i n c o n t a c t i n a c a s s e t t e and both f i l t e r s ashed a t the same time i n a beaker, i t c o u l d not be determined i f any P l i c t r a n was breaking through the f i l t e r s . To answer t h a t q u e s t i o n , the f i l t e r s were separated as d e s c r i b e d . Each f i l t e r was s e p a r a t e l y analyzed. In a d d i t i o n , the volume o f a c i d i n the f i r s t impinger was i n c r e a s e d t o 20 mL, the H 0 t r a p s o l u t i o n was analyzed and the sampling time decreased. The data 3
3
2
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CHEMICAL
0.1 FIGURE 3.
Figure 3.
HAZARDS
0.5 fig Sn/mL
The standard curve
1.0
IN T H E
WORKPLACE
8.
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Breakthrough
Studies with
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115
Table II LABORATORY CHAMBER RESULTS ( ] 2 ) ~ Filter
9
Sn . (ppro) D
Sn ~ (total )
Vol.Air Sampled (L)
Cone. In A i r (yg/L)
0.30
94.2
0.0032
0.75 1.0 0.50 0.25
68.25 61.75 59.8 61.1
0.011 0.016 0.0084 0.0042
7.4 6.3 21.05
60.45 60.45 64.03
0.122 0.104 0.329
7.65 2.25
63.38 63.38
0.121 0.036
c
6FF-GFF »
0.006 nd nd " 0.015 0.02 0.01 0.005 GFF-GN-4 nd " " nd GN-4-GN-4 nd " « nd GFF*-GN-4* nd » nd GFF-GFF* nd HN0 imp A 0.148 " A+ 0.126 " Β 0.421 " B+ nd " C 0.153 " C+ 0.045 11
3
a
= f i l t e r s i n c o n t a c t , both f i l t e r s d i g e s t e d t o g e t h e r as one, f i l t e r t o l e f t was f i r s t i n the sampling t r a i n b = concentration of t i n c = t o t a l yg o f Sn c o l l e c t e d * = coated with CuCl .4NH nd = none detected + = back-up impinger 2
3
116
C H E M I C A L HAZARDS IN T H E W O R K P L A C E
in Table III indicated that increasing the volume of acid and decreasing the sampling time v i r t u a l l y eliminated breakthrough of Sn to the back-up impinger and that HN0 was a better collector than the f i l t e r s . No detectable level of Sn reached the H 0 traps. It also appeared, however, that there was no breakthrough from the f i r s t f i l t e r to the second f i l t e r . To further test this apparent lack of breakthrough, additional samples were collected. In this instance no concurrent acid collection was used. Instead, acid impingers were employed as back-up impingers to the cassettes. If a v o l a t i l e component of Plictran would break through the f i l t e r s , the acid would trap i t . The data in Table IV indicated that the f i r s t f i l t e r effectively collected the Plictran since no detectable levels of Sn were found on the second f i l t e r . It also appeared that Plictran did not v o l a t i l i z e , and pass through the f i l t e r s as evidenced by no detectable levels of Sn in the acid. To further test the preceding r e s u l t s , two additional sets of samples were collected. A l l conditions were the same except sampling times were increased. The data in Tables V and VI sup port the e a r l i e r data and indicate that the f i r s t f i l t e r effec t i v e l y collected the Plictran and that there was no breakthrough or v o l a t i l i z a t i o n . 3
2
Summary and Conclusions This study tested dual f i l t e r combinations compared to con centrated HN0 impingement for sampling an organotin compound, Plictran (tricyclohexyltin hydroxide). Glass fiber and cellulose ester f i l t e r s were studied in two configurations, in direct con tact in 2 piece 37 mm f i e l d cassettes and separated in 3 piece 37 mm f i e l d cassettes. Regular f i l t e r s and f i l t e r s coated with CuCl »4NH were tested in both configurations. The data seemed to indicate that Plictran could be safely collected as a personal sample with a f i l t e r without relying upon HNO3. It appeared that a s i n g l e , uncoated glass fiber f i l t e r was sufficient to c o l l e c t Plictran since breakthrough from f i l t e r s appeared not to be a problem as in e a r l i e r reports. Coated f i l t e r s appeared not to be more e f f i c i e n t than uncoated but more data was needed to complete such a comparison. Coated f i l t e r s increased a i r flow resistance which reduced the sampling flow rate that could be used. 3
2
3
Abstract An air sampling technique for an organotin miticide, Plictran (tricyclohexyltin hydroxide) has been studied. Differ ent types of filtration sampling were compared to impingement of the sample into concentrated HNO . Laboratory sampling consisted of two and three piece field cassettes containing plain and coated glass fiber and cellulose ester f i l t e r s . The coating material was CuCl ·4NH3. The filters were wet-ashed in 2:1 concentrated HNO / concentrated H SO and taken up in 3% HCl as working samples. All 3
2
3
2
4
8.
HOUK A N D BEAULIEU
111
Breakthrough Studies with Plictran
Table III LABORATORY CHAMBER (.12) (43 minute sample time)
Filter
Sn . (ppm)
3
(total)
c
Vol. A i r Sampled (L)
Cone. In Air (yg/L)
nd nd
—
—
—
0.002 nd
0.10
39.99
0.0025
nd nd
—
GFF GN-4
0.002 nd
0.10
38.80
0.0026
HN0 imp A " A+ H0 " A"
0.075 0.004 nd
3.75 0.20
39.99 39.99
0.094 0.005
38.92
0.419
38.92
0.196
GN-4* GN-4 P 4
a i r
GN-4* GN-4 GFF GN-4
„ 4
P
a i r
3
2
HNO3
"
B
H0
" B+ " B"
HNO3
"
C
H0
" c+ " C"
2
2
0.326 nd nd 0.153 nd nd
16.3
7.65
—
—
a = filters separated as described, first f i l t e r typed was first in the sampling train, b = concentration of tin c = total yg of tin collected + = back-up HNO impinger * = coated " = H 0 impinger before pump 3
2
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HAZARDS
IN T H E W O R K P L A C E
Table Iv LABORATORY CHAMBER (12) (32 minute sample time)
Filter GFF GN-4 HN0 imp 3
GFF GN-4 HNO3
imp
GFF GFF* HNO3
imp
*
nd
nd 0.028 nd nd nd 2 sets nd nd
—
—
—
1.25
30.08
0.042
—
__
30.24
0.0083
imp
1.75
30.56
0.057
imp
0.035 nd nd
0.10
30.08
0.0033
imp
0.002 nd nd
GFF GFF* HNO3
"
Cone. In Air (yg/L)
c
0.25
GFF GFF* HNO3
0 c
Vol. A i r Sampled (L)
Sn (total)
0.005 nd nd
GFF GFF* HNO3
Sn . (ppm)
3
Legend same as Table III
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Breakthrough Studies with Plictran
Table V LABORATORY CHAMBER (12) (54 minute sample time)
Filter GFF GN-4 HNO3 imp
GFF GN-4 HNO3 imp
GFF GN-4 HNO3 imp
GFF GN-4 HNO3 imp
GFF GN-4 HNO3 imp
GFF GN-4 HNO3 imp
GFF GN-4 HNO3 imp
GFF GN-4 HNO3 imp
3
Sn . (ppm)
Sn (total)
0.022 nd
D
Vol. A i r Sampled (L)
Cone. In A i r (yg/L)
1.1
50.92
0.022
3.1
51.46
0.060
2.4
49.31
0.049
2.0
50.38
0.040
0.5
49.85
0.010
1.3
51.99
0.025
0.85
51.19
0.017
3.2 9.8
49.04 49.04
0.065 0.201
c
nd
0.062 nd nd
0.048 nd nd
0.040 nd nd
0.010 nd nd
0.026 nd nd
0.017 nd nd
0.064 0.197t nd
Legend same as Table III t Glass fiber f i l t e r s p l i t during sampling.
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HAZARDS
IN T H E W O R K P L A C E
Table VI LABORATORY CHAMBER (12) (73 minute sample time) Vol. A i r Sampled (L)
Cone. In Air (yg/L)
70.1
--
— —
0.037
2.0
65.3
0.032
imp
0.041 nd nd
— —
— —
2.0
69.7
0.028
imp
0.039 nd nd
— —
— —
2.3
65.0
~
— —
0.035
imp
0.046 nd nd
2.85
70.1
0.041
imp
0.057 nd nd
2.2
imp
0.043 nd nd
Sn . (ppm)
Sn (total)
GFF GN-4 HN0 imp
0.052 nd nd
2.6
GFF GN-4
•Filter
3
HNO3
GFF GN-4 HNO3
GFF GN-4 HNO3
GFF GN-4 HNO3
—
0.029
--
2.3
66.8
0.034
imp
0.046 nd nd
1.5
64.2
0.023
imp
0.030 nd nd
— —
— —
2.0
68.6
0.028
imp
0.039 nd nd
Legend same as Table III
— —
— —
— —
GFF GN-4 HNO3
— —
73.0
GFF GN-4 HNO3
— —
— —
— —
GFF GN-4 HNO3
—
c
—
GFF GN-4 HNO3
3
—
— — — —
— —
— —
— —
— — —
— —
8.
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121
samples were analyzed by graphite furnace MS with manual injec tions of 5 μL samples. Data gathered during the study indicated Plictran could be safely collected as a personal sample with a single glass fiber filter without breakthrough of the Plictran . Coated filters did not appear to improve collection efficiency of the organotin compound. Concentrated HN0 appeared to be a more efficient collector of Plictran . 3
Literature Cited 1. Ross, A. Ann. N.Y. Acad. S c i . , 1965, 125, 107-123. 2. Piver, W.T., Environ. Health Perspec.1973, 4, 61-79. 3. Dow Chemical Company, "Material Safety Data Sheet, Plictran 50 W Hiticide"; Midland, Michigan, 1976. 4. Neumann, W.P., "The Organic Chemistry of Tin"; Interscience Pub., London, 1970; pp. 1-282. 5. National Institute for Occupational Safety and Health, "Cri teria for a Recommended Standard . . . Occupational Exposure to Organotin Compounds"; DHEW, NIOSH, Cincinnati, Ohio, 1976; No. 77-115. 6. American Council of Governmental Industrial Hygienists, "Docu mentation of the Threshold Limit Values for Substances in the Workwoom Air . . . Organotins"; ACGIH, Cincinnati, Ohio, 1971. 7. American Council of Governmental Industrial Hygienists, "Documentation of the Threshold Limit Values for Substances in the Workroom Air . . . Tricyclohexyltin Hydroxide, "Plictran )"; ACGIH, Cincinnati, Ohio, 1975. 8. Geissert, J . : Occupational Health and Safety Section, Institute of Rural Environmental Health, Colorado State University, Fort Collins, Colorado, 1978, Personal Communcation. 9. Sinnon, I.: Director of Analytical Services, M&T Chemical Co., Rahway, N . J . , 1979, Personal Communication. 10. Frachman, H . , Tyberg, A . , Branigan, P. Anal. Chem., 1977, 49, 1090-1093. 11. Merganger, J. J . Assoc. Off. Anal. Chem. 1975, 58, 1143-1146. 12. Houk, C.C. "Sampling and Analysis for an Organotin, Plictran (tricyclohexyltin hydroxide)", Master of Science Thesis, Colorado State University, Fort Collins, Colorado, 1980. R E C E I V E D November 13,
1980.
