Anal. Chem. 1980, 52, 1836-1841
1836
LITERATURE CITED (1) Schilling, G. J.: Bright, G. S. Lubrication 1977, 63, 2, 13. (2) Challis, B. C.; Kyrtopoulos, S. A. J . Chem. SOC.,Perkin Trans 7 1979, 299. (3) Hare. C. T.; Montalvo, D. A. Diesel Crankcase Emissions Characterization, EPA Contract No. 68-03-2196: Ann Arbor, MI, 1977. (4) Rounbehler, D. p.; Reisch, J. w.; Coombs, J. R.; Fine, D. H. Anal. Chem. *a70 me.“,
69
I C ,
91-
L,”.
(5) Goff, E. U., unpublished data.
(6) Douglas, M. L.; Kabacoff, B. L.; Anderson, G.A. J . SOC.Cosmet. Chem. 1978, 29, 581-606 (7) Gough, T. A.; Webb, K. S.; Pringuer, M. A.: Wood, B. J. J . Agric. Food Chem. 1977, 25. 663.
RECEIVED for review May 22, 1980. Accepted July 7, 1980. This work was supported by the U S . Environmental Protection Agency under Contract No. 68-03-2719.
Volatile Environmental Pollutants in Biological Matrices with a Headspace Purge Technique Larry C. Michael,* Mitchell
D. Erickson,
Sandra P. Parks,’ and Edo D. Pellizzari
Chemistry and Life Sciences Group, Research Triangle Institute, P.O. Box 12 194, Research Triangle Park, North Carolina 27709
Gas stripping and dynamic headspace anatysis were evaluated as methods for purging volatile halogenated organics from human biological samples (urine, blood, milk, and adipose tissue). I n gas stripping, volatile compounds are purged by bubbling an inert gas through a liquid sample at elevated temperature. The purged organic materials are trapped on the polymeric sorbent Tenax GC for subsequent gas chromatographic analysis. In dynamic headspace analysis, the gas passes over rather than through the solution. This procedure is particularly applicable to samples which foam, such as biological samples. Validation experiments involved recovery studies on fortified samples by both gas chromatography and mass balance experiments with I4C-labeled compounds. Recoveries were generally 60-95 % The procedure was developed to accommodate a high sample throughput by using a simple apparatus and was intended for purging of the sample followed by analysis of the Tenax GC cartridge by thermal desorption/gas chromatography/mass spectrometry/computer.
.
Investigation of volatile organic compounds in human tissues has received recent attention due to the occurrence of such compounds in t h e environment (1-3). Many of these compounds, particularly halogenated species, are known or suspected carcinogens, and an assessment of body burden is essential to an understanding of their potential health effects. A number of techniques developed for t h e determination of volatile organic compounds in water, particularly drinking water, were considered for application to human tissue samples. T h e methods fall into six basic categories: (1)solution purge (gas stripping) (4-6); (2) dynamic headspace purge ( 7 , 8); (3) solvent extraction (9, 10); (4) liquid-phase adsorption on polymeric sorbents (11-13); (5) direct aqueous injection (14-16); (6) static headspace analysis (17, 18). Solvent extraction, using high- or low-boiling solvents, generally suffers from poor efficiency even when multiple extractions are employed (19). Direct aqueous injection lacks adequate sensitivity for tissue analysis due to injection volume limitations and, in addition, would present large matrix interferences. Adsorption of volatile organics from a biological matrix directly Present Address: Northrop Environmental Technology Center, Research Triangle P a r k , NC 27709. 0003-2700/80/0352-1836$01 .OO/O
onto polymeric sorbents is highly susceptible to clogging which may result in significant flow alterations (20). Static headspace analysis requires knowledge of t h e equilibrium coefficients between gas and liquid phases, as well as rigid control of the sample temperature, headspace volume, and other parameters. In addition, except for compounds which strongly favor the gas phase (e.g., highly volatile, water-insoluble substances), static headspace analysis lacks sufficient sensitivity. In light of these difficulties, actual experimental investigations were performed only for gas stripping and dynamic headspace techniques in combination with vapor collection on Tenax GC. Gas stripping analysis involves bubbling an inert gas through the solution t o purge t h e volatile organic materials from the sample, followed by collection of the entrained vapor on a polymeric sorbent. This technique has been shown t o be extremely sensitive for water insoluble organics with boiling points less t h a n approximately 150 “C ( 2 1 ) . Dynamic headspace analysis is similar to gas stripping except the inert gas passes over, rather than through, t h e solution. T h e purpose of this research was t o develop and validate analytical procedures for determining volatile halogenated organic compounds in human blood, urine, milk, and adipose tissue. The approach to the problem involved complementary, parallel studies; (1)recovery studies with radiolabeled compounds and (2) recovery studies with nonradiolabeled substances. T h e experiments with radiolabeled compounds measured recoveries both as the percentage of fortified material detected on the sorbent cartridge and as the percentage remaining in the sample following gas stripping or dynamic headspace analysis. This experimental approach permitted construction of a “mass balance” for the entire procedure. Experiments with nonradiolabeled compounds provided recoveries of compounds with a broad range of volatilities t o permit quantitation of compounds detected in actual samples. T h e use of two independent validation procedures not only assures the precision and accuracy of the analytical results b u t also guards against systematic errors.
EXPERIMENTAL SECTION Apparatus. The apparatus used in gas stripping and dynamic headspace analyses are shown in Figure 1. Two biological media, blood and urine, were used for analytical method development. Gas stripping, because of its inherent sensitivity advantage, was studied first. The apparatus (Figure l A ) , consisted of a roundbottom flask containing a gas dispersion tube for purge gas inlet, a thermometer, and a Teflon-coated, magnetic stir bar. The flask was topped with a short glass tube containing a small plug of glass G 1980 American Chemical Society
ANALYTICAL CHEMISTRY, VOL. 52, NO. 12, OCTOBER 1980
1837
A 0 Figure 1. (A) Through-solution gas stripping apparatus. (B) Dynamic headspace gas stripping apparatus
wool to trap water aerosols. This had been shown in previous studies to reduce water uptake by the sorbent cartridge ( 6 ) . Attached to this trap was a glass cartridge packed with 1.5 X 6.0 cm (1.5 g) of 36/60 mesh Tenax GC (Applied Science Laboratories,, Inc.). A flow of helium, prepurified by passing through molecular sieve and activated carbon, was passed through the stirred, heated solution and the entrained volatile materials adsorbed by the Tenax GC. Tenax GC was chosen as the sorbent for these experiments on the basis of previous successful use in purge and trap analyses of water (6) and our previous work to determine breakthrough volumes and thermal desorption conditions (22). Further considerations were its low affinity for water (23) and its high thermal stability compared with other sorbents (24, 25). The headspace technique used an identical apparatus with the exception that the submerged, fritted-glass inlet tube was replaced by an open-end tube terminating just above the solution surface (Figure 1B). In this apparatus the helium flow passed over the sample and through the Tenax GC cartridge. Materials a n d Methods. ,411 chemical compounds in this study were reagent grade (various sources) and were used without further purification. Carbon-1-i labeled chloroform (California Bionuclear Corp.), carbon tetrachloride (Amersham Corp.), chlorobenzene (Amersham Corp.), and bromobenzene (New England Nuclear) were quantitatively transferred to 50 mL of redistilled methanol in screw-cap vials. Solvents were exclusiveljr "distilled-in-glass'' grade (Burdick and Jackson Laboratories). Tenax GC was purified by Soxhlet extraction for 24 h each in redistilled methanol and pentane. After being dried under vacuum a t 60 "C for 18 h and sized into 35/60 mesh, 1.5 cm i.d. X 6.0 cm cartridges were packed and thermally desorbed a t 270 "C for 30 min in a stream of helium. Gas chromatographic analysis was performed on a Varian 3700 gas chromatograph with flame-ionization detection (GC/FID) using SE-30 glass SCOT columns prepared in-house (26). A Packard Tri-Carb Model 3255 liquid scintillation counter operated in the external standard mode was used for carbon-14 assay. Toluene-Triton X-Omnifluor (New England Nuclear), in the proportions, 3 L:l L:15 g, respectively, was used as the counting cocktail. Calibration curves of the external standard ratio vs. counting efficiencies were constructed by using carbon-14 toluene standard (New England Nuclear) quenched with varying amounts of carbon tetrachloride. This curve was used to convert counts per minute (CPM) obtained from the counter to disintegrations per minute (DPM). Scintillation counting was conducted on each sample until loo00 counts had been accumulated. This represents a counting error of *2 9i. Recovery Studies with Radiolabeled Compounds. Recovery studies using carbon-14-labeled chloroform, carbon tetrachloride, chlorobenzene, and bromobenzene were performed to assess the
percentages of material collected by and desorbed from the Tenax GC trap, lost through connections in the apparatus and remaining in the sample matrix. This dowed construction of a mass balance for the analysis. Recoveries were assessed for the sorption/desorption process alone, the gas stripping technique, and the dynamic headspace technique. To isolate the purging efficiency from the sorption/desorption process, we evaluated recoveries of cl2mpounds loaded directly onto Tenax GC cartridges. The apparatus illustrated in Figure 2 was used to load compounds onto the Tenax GC. Methanol solutions of the carbon-14 labeled compounds were injected through the septum of the loading tube into a heated (106 "C) chamber where they were vaporized and swept into the Tenax GC cartridge in a nitrogen stream of 20 mL/min. Approximately 15 min was required to vaporize and load up to 67.6 pL (0.75-1.42 pg). Loaded cartridges were thermally desorbed for 10 min in a desorption chamber (Figure 2) (27)a t 270 "C under a helium flow of 20 mL/min. Effluent gas from the desorption chamber containing the desorbed compounds was bubbled into three vials in series containing 15 mL of scintillation counting cocktail. These samples were subsequently analyzed for carbon-14 by liquid scintillation counting. Triplicate standards of each compound were prepared by injecting known amounts of radiolabeled material directly into counting vials containing 15 mL of cocktail. Recoveries were calculated by comparing radioactivity detected on the Tenax GC cartridge to the average of that detected in the triplicate standards. Recovery studies on blood and urine by both the dynamic headspace and gas stripping techniques were conducted by using 25 mL of sample diluted with 25 mL of distilled water fortified with 1 pg (-98000 DPM) of a radiolabeled compound in methanol. The temperature was then raised rapidly from 20 to 50 "C and the sample purged with 25 mL/min helium for 90 min with vigorous stirring. Recovery of identical compounds from 50 mL of raw cow's milk was performed at 70 "C. After the sample was purged, 1-mL aliquots were oxidized by using a Packard Model 306 Tri-Carb sample oxidizer with the resulting [14C]carbondioxide being trapped in Carbo-sorb arid counted in Permafluor counting cocktail (Packard Instrument (20.). Standard Combustion samples (Packard Instrument Co.) were used for validation of the combustion process. Recovery Studies w i t h Nonradiolabeled Compounds. Recovery efficiency of model compounds was determined in a manner analogous to that used with radiolabeled compounds except for the sample fortification technique and the analysis of compounds desorbed from the Tenax GC cartridge. Standard mixtures of methylene chloride, chloroform, bromodichloromethane, tetrachloroethylene, chlorobenzene, and rn-dichlorobenzene were prepared in dry, prepurified nitrogen gas
1838
ANALYTICAL CHEMISTRY, VOL. 52, NO. 12, OCTOBER 1980 TENAX GC CARTRIDGE
3 W A Y STOPCOCK
SEPTUM
ri
CARBON CARTRIDE
1 ?
e- NP
FLOW (30ml/min)
f
\
/
TEFLON UNIONS
LOADING TUBE (wrapped with heating t a p e )
t -DESORPTION
CHAMBER
RUBBER STOPPERS
. LIQUID LEVEL S C I N l.ILLATION COUNTER VIALS
Flgure 2. Sorption/desorption apparatus for Tenax GC cartridges
m
- - - - ---_
,---I T E F L O N SEAL SPRING
I
V A L V E POSITION A (SAMPLE OESORPTIONI
I
I
I
M E T A L SEAL
I Carrier Purge Gas I
I
HEATING BATH
I 1
---- - - - - __ - CARRIER
-
V A L V E POSITION B (SAMPLE INJECTION)
CAREONTRAP
TWO POSITION
I I 4 I I
I Gar Carrier
l:,!
Purge
Ventl
Gas
HEATING AND COOLING BATH
&%aillJ
I I
I
LIQUID N I T R O G E N
Flgure 3. Thermal desorption inlet manifold for Tenax GC cartridges
at approximately 75 " C by injecting small amounts (1-5 pL) of the pure liquid into a 2.0-L spherical glass bulb. These mixtures were equilibrated with stirring for 1 h. T o evaluate recoveries from actual samples, we injected aliquots (1.0 mL) of the vapor standard into the aqueous samples contained in a septum-capped bottle at 4 "C using a gastight syringe (Precision Sampling Corp.). After equilibration a t 4 "C for 1 h, the spiked samples were transferred to the purge apparatus (Figure 1B).The solution was stirred, heated to 50 "C, and either the headspace above or the solution itself was purged for 90 min a t 25 mL/min of helium. Exposed Tenax GC cartridges were desiccated for 1 2 h by storing in capped culture tubes containing approximately 2 g of anhydrous calcium sulfate. This effectively removed gross water vapor from the cartridge which interferes with thermal desorption of the cartridges and degrades the gas chromatographic column. Tenax GC cartridges were loaded directly with 1.0-mL aliquots of the vapor mixture and were used as quantitation standards.
Exposed sample cartridges and standard cartridges were analyzed by GC/FID on a 0.38 mm i.d. X 80 m, 1% SE-30 glass SCOT column, temperature programmed from 30 to 220 OC a t 4"/min. Compounds were removed from the Tenax GC for injection into the GC by thermal desorption using the system illustrated in Figure 3. A detailed study of this apparatus is presented in a previous publication (28). This system consists of four main components: a desorption chamber, a six-port, two-position, high-temperature, low-volume valve (Valco Instruments, Inc.), a Ni capillary cryogenic trap, and a temperature controller. The stainless steel thermal desorption chamber and six-port valve are encased in a common aluminum sandwich which serves as a heating block. The chamber itself has an overall length of 12 cm and accommodates a Pyrex sampling cartridge of dimensions 13 mm i.d. X 16 mm 0.d. and 10-cm length. Two, 150-W, 115-V heating cartridges are used to heat the aluminum sandwich, and the temperature is controlled and monitored with iron-
ANALYTICAL CHEMISTRY, VOL. 52, NO. 12, OCTOBER 1980
1839
Table I. Recovery of I4C-Labeled Compounds from Tenax GC by Thermal Desorption compd loaded
volume loaded, p L
mass loaded, pg
av DPMO
chloroform carbon tetrachlorideC chlorobenzene bromobenzene
16 68 30 13
0.56 0.75 1.2 1.4
87 000 74 000
av % recoveryb ( + S D ) 97i902 99i 97t
8 5 000 80 000
2 8 2 2
First cartridge, first impinger only. C"ine replicates.
Based on three cartridges.
0 062 in o NI C A P I L L A R Y
0 04 in i d
THERMOCOUPLE 45cm
0
1
8
12
16
PO
24
28
32
18
TlME ,rnl",
Figure 5. GClFID of halogenated hydrocarbons by thermal desorption from Tenax GC (80 m X 0.4 mm i.d. 1 " ! SE-30 i- 0 . 3 2 % Tullanox 220 "C at 4 "C/min; SCOT column; temperature programmed, 30 carrier (He) flow, 1.5 mL/min)
-
1/16 in SWAGELOK UNION
9c
1~
2
3
m
4
c
c
m
~
Figure 4. Cryo-heater module for inlet manifold
constantan thermocouples and output on a pyrometer (Omega Engineering, Inc.). The desorption chamber is connected to the valve with a short section of Ni capillary tubing (0.50 mm i.d., 1.57 mm 0.d.). Similar capillary tubing is used for the cryogenic trap (Figure 4). This trap, constructed of aluminum, is cooled to -195 "C by passing cryogenically cooled nitrogen gas through 1.57 mm 0.d. tubing prior to entry into the body of the trap. This allows collection and concentration of vapors desorbed from the sorbent cartridge. The vapors are injected onto the GC column by rapid heating of the capillary trap to 270 "C provided by a 150-W cartridge heater located inside the aluminum cylinder. The desorption chamber is interfaced to the capillary GC column with a minimal length of gold-plated Ni capillary tubing (0.40 mm i.d., 1.57 mm o.d.), deactivated with OV-17. Connection between the Ni transfer line and glass capillary is made with a 1.57 mm stainless steel "zero dead volume" union (Swagelok, Crawford Fitting Co.) using stainless steel and Vespel ferrules. In a typical thermal desorption/injection cycle, an exposed cartridge is placed in the preheated (240 "C) chamber with a flow of He gas (15 mL/min) through the cartridge to purge the desorbed vapors into the cryogenic trap; this constitutes valve position A (Figure 3). After 8 min of thermal desorption, the six-port valve is rotated to position B, the temperature on the capillary trap is rapidly raised (>100"/min), and carrier gas sweeps the vapors onto the gas chromatographic column. Following a 3.5-min injection period, the valve is returned to position A, the trap heater is turned off and the cartridge is removed from the desorption chamber in preparation for the next injection. A representative chromatogram of a standard mixture of halogenated hydrocarbons is shown in Figure 5 . Human adipose tissue specimens were obtained from pathology departments of local hospitals, fortified with halogenated compounds and purged to assess recovery. Samples (5 g) of frozen human fat were cut from a larger mass with a scalpel, sectioned, and transferred to a lOO-mL, round-bottom, three-necked flask. Aliquots of distilled water (60 mL) were fortified as discussed above. The water was added to the tissue already contained in the purge flask and the mixture macerated with a Virtis tissue homogenizer. The purge apparatus was immediately assembled
and heated to 50 O C and the headspace purged for 30 min at 25 mL/min of helium. The exposed cartridges were desiccated and analyzed as described above.
RESULTS AND DISCUSSION Blood and urine are very susceptible to foaming, especially a t elevated temperatures. Consequently, attempts t o purge volatile organics from these media a t 60 "C by gas stripping with helium a t 25 m L / m i n resulted in a severe foaming problem. Reduction of the temperature to 30 "C and the flow t o 15 mL/min did not significantly reduce foaming. The use of either a loose glass wool plug in the neck of the flask to break the bubbles or a "foam trap" similar to t h a t described by Bellar a n d Lichtenberg ( 4 ) was also unsuccessful. Chemical agents were also tested as a means t o control foaming. Dow Corning Antifoam A spray was quite effective in controlling foaming; unfortunately t h e hydrocarbon a n d fluorocarbon content of the spray contributed significantly to the background on the Tenax GC sorbent,, making d a t a interpretation extremely difficult. Octanol was moderately successful as an antifoaming agent but was too volatile for this application. Dynamic headspace purge analysis appears t o be the simplest procedure for determining volatile compounds in biological media. Like gas stripping analysis, dynamic headspace purge depends on the partition between the aqueous and gas phases and t h e surface area of t h e interface. T h e partition is affected by a number of factors including temperature and water solubility of the compounds of interest. Although the gas-water interfacial area is significantly smaller in t h e headspace technique than in gas stripping and hence the rate of transport of volatile materials from the liquid to gas phase is diminished, several parameters can be adjusted to optimize t h e purge efficiency in headspace analysis. Higher temperatures are possible since t h e gas does not flow through the solution and foaming is less of a concern. Furthermore, vortexing t h e solution with rapid stirring increases the interfacial area. Method Validation-Radiolabeled Compounds. Thermal desorption of radiolabeled compounds from Tenax GC
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ANALYTICAL CHEMISTRY, VOL. 52, NO. 12, OCTOBER 1980
Table 11. Recovery of I4C-Labeled Compounds from Blood av % re% r e - covcovery ery
mass loaded,
DPM
Pg
loaded
chloroform
1.5
92000
carbon tetrachloride
0.79
78000
chlorobenzene
1.2
9 0 000
compd
bromobenzene
94 93 93 92 84
89 90
88 92 77 74 90
84 000
1.2
94
81
Method Validation with Nonradiolabeled Compounds.
Table 111. Recovery of 14C-Labeled Compounds from Urine mass loaded, compd
pg
av 7% re-
DPM %reloaded covery
covery (iSD) 84
i
2
64
i
6
chloroform
1.5
94000
carbon tetrachloride
0.81
80 000
chlorobenzene
1.1
90000
bromo benzene
0.0 13
900
large amount of material rather than incomplete desorption. Less t h a n 1% of the total amount of each compound was found in the second impinger, indicating that the compounds were not breaking through t h e scintillation cocktail. Recoveries of carbon-14-labeled chloroform, carbon tetrachloride, chlorobenzene, and bromobenzene from blood, urine, and milk by headspace purge (Tables 11-IV), were generally 90% or above. With the exception of bromobenzene in blood, where 8% of the total radioactive material remained unpuged, no significant radioactivity was found in the purged blood and urine samples. Consequently, losses have been attributed t o leaks in the purge apparatus. Installation of Teflon sleeves on the standard taper joints eliminated such losses. The lower recovery of bromobenzene from blood and of chlorobenzene and bromobenzene from milk was attributed to the relatively low volatility of these compounds in conjunction with matrix effects which tend to retard purge efficiency.
84 84 85 57 67 67 90 88 90 147 114 107
89i 2 1 2 3 5 21
cartridges directly into scintillation cocktail was found t o be very efficient (Table I). T h e low recovery of carbon tetrachloride was attributed to incomplete loading of this relatively
Table V illustrates t h e recovery of six model halogenated hydrocarbons which span t h e range of volatilities generally addressed by purge and t r a p techniques. Four separate analyses were performed t o assess both recovery and reproducibility. In all three media studied, quantitation of methylene chloride and, in some cases, chloroform was extremely difficult due to background interferences in the chromatograms. T h e recovery d a t a for blood and urine illustrate two fundamental trends: (1) t h e recovery decreases as the boiling point of the compound increases (volatility decreases) and (2) t h e reproducibility improves with increasing boiling point. The inverse relationship between recovery and boiling point is expected and has been observed in similar studies with water samples (6). This effect is compounded in complex matrices where stripping efficiency may be further suppressed by adsorption of the compounds of interest on large organic molecules or suspended particulate materials. T h e improved reproducibility with the less volatile compounds suggests that the more volatile materials are being lost during fortification
Table IV. Recovery of '%-Labeled Compounds from Milk mass loaded, u g
DPM loaded
chloroform
1.5
94 000
88 89 88
carbon tetrachloride
0.81
80 000
90 93 82
chlorobenzene
1.1
90 000
62 63 65
bromo benzene
1.3
8 5 000
34 38 34
compound
av % recovery
% recovery
% retained
av % retained
6 6 6 88
i
2
6 i 2 >2 >2 7.0
88
63
i
*
6
3 t 3 29 26 24
2
26
i
3
51
i
13
58 36 57
35
t
3
Table V. Percent Recovery of Halogenated Hydrocarbons from Human Biological Tissues urine
blood
amt spiked, compd methylene chloride chloroform bromodichloromethane tetrachloroethylene chlorobenzene rn-dichlorobenzene
Yg
8.0
8.2 10
8.5 5.5 6.4
amt spiked,
amt spiked, % recovery
110 = 8 1 2 0 * 33 110 k 3 1
loot
18 9 8 2 19 86 II 11
!J g
7.0 8.2 10
8.4 5.6 7.5
adipose tissue
% recovery
pg
4 8 i 30 79 2 27 l l O t 23 72 i 1 5 86 t 1 4 79 t 9
0.88 1.8 1.5
1.7 2.3 2.5
% recovery
80k 46 i 36 * 52 t 13i 57 i
12 27 25 42 8 26
ANALYTICAL CHEMISTRY, VOL. 52, NO. '12, OCTOBER 1980
or through leaks in the apparatus. This agrees with observations made with radiolabeled compounds wherein the mass balance left approximately 2-10% unacceunted for. T h e recoveries of halogenated hydrocarbons from human adipose tissue (Table V) are quite variable. Great difficulty was encountered in quantitative introduction of a representative fortified sample into the container for analysis. Consequently, variations in recovery may be attributed to losses during tissue maceration and transfer.
APPLICATION T h e techniques described have been successfully employed in the analysis of blood and urine collected from individuals residing in the Old Love Canal area of Niagara Falls, NY (27). Complete results of the analyses by G C / M S / C O M P are reported elsewhere (29). Among the compounds identified were chloroform (0.8-20.1 Fg/L), carbon tetrachloride (not det e c t e d 4 . 1 Fg/L), trichloroethylene (not detected-2.6 bg/L), chlorobenzene (not detected-16.8 pg/L), and dichlorobenzene (not detected-67.7 pg/L).
CONCLUSIONS Dynamic headspace analysis can be successfully applied to samples which present foaming difficulties in conventional purge and trap analysis. Volatile organic materials in biological fluids, a matrix which displays an overt foaming tendency, have been efficiently purged at the 10 ppb level with this technique. Compounds with boiling points less than or equal to bromobenzene (156 O C ) and which are water insoluble can be determined.
ACKNOWLEDGMENT T h e authors gratefully acknowledge J a n e Barclay, Joe Davis, and R. Neil Williams for their assistance in laboratory a n d field studies. Appreciation is also extended to William Librizzi and his staff, U.S. EPA, Region 11, and to Joseph Breen and Vincent J. DeCarlo, Project Officers, Office of Toxic Substances, U.S. EPA, Washington, DC.
LITERATURE CITED (1) Kopfler, F. C.; Metton, R. G.; Lingg, R. D.; Coleman, W. E. "Identification and Analysis of Organic Pollutants in Water"; Keith, L. H., Ed.; Ann Arbor Science: Ann Arbor, MI, 1976; Chapter 6. (2) Keith, L. H.; Garrlson, A. W.; Allen, F. R.; Carter, M. H.; Floyd, T. L.; Pope, J. D.; Thurston, A.D., Jr. "Identification and Analysis of Organic Pollutants in Water"; Ketth, L. H., Ed.; Ann Arbor Science: Ann Arbor, MI, 1976; Chapter 22. (3) Pellizzari, E. D. "Analysis of Organic Air Pollutants by Gas Chromatography and Mass Spectrometry"; EPA-600/2-77-100; US. Environmental Protection Agency, Atmospheric Chemistry and Physics Division, Environmental Sciences Research Laboratory: Research Triangle Park, NC, 1977; p 114. (4) Bellar, T. A.; Lichtenberg. J. J. "The Determination of Volatile Organic Compounds at the Fg/L Level in Water by Gas Chromatography"; EPA-67014-74-009; U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory: Cincinnati, OH, 1974; p 33.
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(5) Keith, L. H.; Lee, K. W.; Provost, L. P., presented at the Symposium on Measurement of Organic Pollutants in Water", American Society for Testing and Materials, Denver, 1978. (6) Pellizzari, E. D.; Zweidinger, R. A,; Erickson, M. D. "Environmental Monitoring Near Industrial Sies: Brominated Chemicals, Part Iand 11"; EPA-560/6-78-002; U.S. Environmental Protection Agency, Office of Pesticides and Toxic Substances: Washington, DC, 1978; p 325. (7) Mieure, J. P.; Dietrich, M. W. J . Chromafogf. Sci. 1973, 11, 559-570. (8) Sievers. R. F.; Shapiro, R. H.; Watton, H. F.; Eiceman, G. A,; Barley, R.. presented at 174th National Meeting of the American Chemical Society, Chicago, IL, Aug 1977. (9) Deetman, A. A,; Demeulemeester. P. Anal. Chim. Acta 1976, 82, 1-17. (10) . , Shadoff. L. A.: Hummel. R. A,: Lamoarski. L.:,~ Davidson.. J. - H. Bull. Environ. Contam. Toxicbl. 1977, 18: 478-85. (11) Suffet, I.H.; Brenner, L.; Radziul, J. V. "Identification and Analysis of Organic Pollutants in Water"; Keith, L. H., Ed.; Ann Arbor Science: Ann Arbor, MI, 1976; Chapter 23. (12) Aue, W. A.; Kapila, S.: Hastings, C. R. J . Chromatogr. 1972, 73, 99-104. (13) Welebir. A.; d'Angelo, W. M.; Bigelow, S. W.; Aldridge, M. H. "Evaluation of High Performance Liquid Chromatography Packings for the Concentration and Separation of Organic Materials in Water"; AD-A053, 6524ST National Technical Information Service: Springfield, VA. (14) McKinney, J. D.; Maurer, R. R.; H a s , J. R.; Thomas, R. 0. "Identification and Anaksis of Organic Pollutants In Water"; Keith, L. H.. Ed.; Ann Arbor Science: Ann Arbor, MI, 1976; Chapter 25. (15) Nicholson, A. A.; Meresz, 0.;Lemyk, B. Anal. Chem. 1977, 49, 8 14-8 19. (16) McAuliffe, C. Nature (London) 1963, 200, 1092-1993. (17) Budde, W. L. "Headspace Analysis: A Quick Qualitative Technique for Volatile Organic Compounds": U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory: Cincinnati, OH, 1975. (18) Hachenberg, H.; Schmidt, A. P. "Gas Chromatographic Headspace Analysis"; Heyden: London, 1977; p 350. (19) Burnham, A. K.; Calder, G. V.; Fritz, J. S.; Junk, G. A,; Svec, H. J.; Willis, R. Anal. Chem. 1972, 44, 139-142. (20) Bursey, J. T.; Hines, J. W.; Lee, S. G.:Michael L. C.; Pellizzari, E. D.; Rosenthal, D. W.: Sheldon, L. S.; Sparacino, C. M.; Tomer, K. B. "Master Scheme for the Analysis of Organic Compounds in Water, Part I: State-of-the-Art Review of Analytical Operations": EPA Contract No. 68-03-2704, Jan 1979. (21) Pellizzari, E. D. "Identlfication of Components of Energy-Related Wastes and Effluents"; EPA-600/7-78-004; U.S. Environmental Protection Agency, Environmental Research Labotatory: Athens, GA, 1978, p 524. (22) Pellizzari, E. D. "Development of Analytical Techniques for Measuring Ambient Atmospheric Carcinogenic Vapors": EPA-600/2-75-076: U.S. Environmental Protection Agency, Environmental Sciences Research Laboratory: Research Triangle Park, NC, 1975; p 201. (23) Janak, J.; Ruzickova, J.; Novak, J. J. Chromatcgr. 1974, 9 9 , 689-696. (24) Pellizzari, E. D.; Bunch, J. E.; Carpenter, B. H.; Sawicki, E. Envkon. Sci. Technol. 1975, 9 , 552-555. (25) Butler, L. D.; Burke, M. F. J . Chromatogr. Sci. 1976, 14, 117-122. (26) Hines, J. W.: Shapiro, R.; Schwartz, A,; Pelllzzari, E. D., unpublished data, 1979. (27) Pellizzari, E. 0.; Erickson, M. D.; Zweidinger, R. A. "Formulation of a Preliminary Assessment of Halogenated Organic Compounds in Man and Environmental Media"; EPA-560/13-79-116; US. Environmental Prctection Agency, Office of Pesticides and Toxic Substances: Washington, DC, July 1979; p 469. (28) Pellizzari, E. D.; Carpenter, B. H.; Bunch, J. E.; Sawicki, E. Environ. Sci. Technol. 1975, 9 , 556-559. (29) Barclay, J.; Bursey, J.; Castillo, N.; Cooper, S. D.; Davis, J. M.; Erickson, M. D.; Harris, 8. S. H.; Michael, L. C.; Pellizzari, E. D.; Smith, D.: Tomer. K. 8.:Zweidinger, R. A. Biomed. Mass Spectrom., in press.
RECEIVED for review October 29, 1979. Accepted J u n e 30, 1980. This work was supported by U.S. Environmental Protection Agency Contracts 68-01-4731 and 68-01-3849.
