1158
Anal. Chem. 1984, 56, 1158-1162
Table V. Weight Percent of Oxygen Found on Resid Sample run no.
Oita-Conway method (1954)
4 5
0.237 0.51 8 0.522 0.243 0.202
av
0.344
1 2
3
proposed method 0.270 0.265 0.287 0.271 0.282
t
0.178
0.274
i:
0.009
they ranged from 0.06 to 1% oxygen. The average determined values were within 10% of the calculated values and the average relative standard deviation was 5.58%. The standard deviation is larger in the 1% range. The larger deviation is due to the nonlinear response of the infrared detector for carbon monoxide in the high range. Also, as the sample size taken is quite small, the inherent weighing error becomes significant. For this reason, this method should be used for samples containing less than 1 % oxygen. A resid sample was analyzed by the direct oxygen method developed by Oita in 1954 and by the trace oxygen method
described here. The results are shown in Table V. The values shown for the direct oxygen method have a wider spread and greater standard deviation than the new method. This is not surprising since the allowable range for the direct oxygen method is 0.3% absolute. In conclusion, a method of determining oxygen in the 0.01% range is described. The method can be used for the determination of oxygen in heavy samples such as heavy gas oils and resids. For this reason, it is well suited for studies of materials such as shale oil, liquefied coals, and petroleum resids. Registry No. Oxygen, 7782-44-7; carbon monoxide, 630-08-0.
LITERATURE CITED (1) (2) (3) (4) (5) (6)
Schutze, M. Anal. Chem. 1939, 718, 241. Unterzaucher, J. 8er. Dtsch. Chem. Ges. 8 1940, 73, 391. Olta, I . J.; Conway, H. S. Anal. Chem. 1954, 26, 600. Simon, W. Helw. Chim. Acta 1963, 4 6 , 2369. Oita, I. J. Anal. Chim. Acta 1960, 22, 439. Olta, I. J. U S . Patent No. 2774588, 1956.
RECEIVED for review December 19,1983. Accepted February 13, 1984.
Determination of Nitrated Polycyclic Aromatic Hydrocarbons in Diesel Particulates by Gas Chromatography with Chemiluminescent Detection Wing C. Yu* Thermo Electron Corporation, Analytical Instruments, 101 First Avenue, Waltham, Massachusetts 02254 David H. Fine New England Institute for Life Sciences, 125 Second Avenue, Waltham, Massachusetts 02254 Kin S. Chiu and Klaus Biemann Department of Chemistry, Massachusetts Institute of Technology, Cambridge,Massachusetts 02139
An analytical technique Is descrlbed for the determlnatlon of nltrated polycyclic aromatlc hydrocarbons (nltro-PAH) In dlesel partkulates. It Involves the use of caplllary gas chromatography for the separatlon of nltro-PAH and subsequent detectlon by chemllumlnescence. The detectlon llmlt of the method Is determined to be 10-25 pg Injected oncolumn. l-Nltronaphthalene, 2-nltronaphthalene, P-nltrofluorene, and l-nltropyrene were selectively detected In the sample. The presence of l-nltronaphthalene and l-nltropyrene were unequlvocally conflrmed by mass spectrometry. Because of detector sekctlvlty to nltro compounds, the presence of PAH and related derlvatlves does not Interfere with the analysis. The technlque Is useful for the screenlng of nltroaromatlcs In complex envlronrnental samples.
During the past several years, considerable interest has been focused on the determination of nitrated polycyclic aromatic hydrocarbons (nitro-PAH) in a number of matrices and environmental samples by using various techniques (1-6). Because of their facile formation in experiments simulating environmental conditions (7,8) and the potent direct-acting mutagenicity observed in Salmonella assays (9,lO) and car0003-2700/84/0356-1158$01.50/0
cinogenicity (11)of some members of the class, the nitro-PAH have been postulated to pose a potential health hazard in the human environment. The determination of nitro-PAH in environmental samples is complicated by several factors. First, the complexity of sample matrices such as diesel particulates and coal combustion products complicates the identification of specific nitro-PAH isomers in the sample. Also, a number of closely related PAH and their derivatives could coelute with the nitro-PAH. Second, there is a lack of adequate nitro-PAH reference standards to establish retention behavior. At present, the availability of pure nitro-PAH isomers is limited to the few compounds reported in the literature and those available commercially. Even for commercially available standards, the presence of minute impurities has caused a misinterpretation in the results of mutagenic assays (12). Third, the number of possible nitro-PAH isomers increases as the molecule becomes larger; while only two isomers are possible for the two-ring nitronaphthalene, 12 or more mononitrated isomers are possible for the five-ring PAH with molecular weight 252, such as benzopyrenes, benzofluoranthenes, and perylene. Thus, the positive identification of a specific compound would require, a priori, the efficient separation of the isomers. Fourth, the nitro-PAH have been 0 1964 Amerlcan Chemical Society
ANALYTICAL CHEMISTRY, VOL. 56, NO. 7, JUNE 1984
found to be present at substantially lower levels than their parent compounds or other PAH derivatives. Thus, extensive workup procedures would be required for the isolation and concentration of these compounds before they could be characterized by currently available instrumentation. TO overcome these problems, there is a need to develop more selective and sensitive analytical techniques. The efficient separation of a large number of PAH isomers by high-resolution capillary column gas chromatography (HRGC) is now routine. The use of HRGC with specific detectors for nitro compounds should offer advantages when analyzing complex matrices. Several detectors for gas chromatography such as electron capture (ECD), nitrogen-phosphorus (NPD), and flame ionization (FID) offer some degree of sensitivity and selectivity for nitro compounds. However, when complex environmental matrices are encountered, these detectors lack the specificity needed to be operated at high sensitivity. This was recently demonstrated in detail by Phillips et al. (13)in the determination of nitroaromatics in biosludges. In their report, only the TEA Analyzer was shown to have adequate selectivity for quantitative analysis at the subnanogram level of nitro compounds in environmental media. The detailed principle of operation of the TEA analyzer is described elsewhere (14, I$). Briefly, effluent from the chromatograph enters a catalytic pyrolyzer, where NO2 is released from organic nitro compounds and simultaneously converted into the nitrosyl radical (NO) by the catalytic surface. Solvent vapors and pyrolysis products are then removed by a cold trap which is maintained a t about -120 "C. The NO survives the cold trap and is then reacted with ozone in the reaction chamber at reduced pressure to produce a characteristic infrared chemiluminescent reaction, the intensity of which is monitored by an infrared-sensitive photomultiplier tube. While the technique is sensitive at the picogram level, it is also highly selective. The rejection ratio of the TEA analyzer to hydrocarbons and other N-containing organics is greater than lo6 to 1. The selectivity stems from four factors. First, only compounds which have the NOz or NO functional group can give a response. Second, the reactive species must survive the -120 "C cold trap. For highly contaminated samples, a -160 "C trap can be used. Third, the reactive species must react with ozone to produce a chemilumnescent light in the narrow wavelength range of 0.6-2.8 pm. Fourth, the reaction with ozone must be rapid enough to occur while the effluent is in the reaction chamber and not in the vacuum pump. The TEA analyzer has been used extensively for the selective determination of N-nitroso compounds in a variety of matrices (16,17).Recent studies have shown that by operating the catalytic pyrolyzer above 800 "C, molar or near molar response is observed for nitroaromatics and nitro-based explosives (14,18). A preliminary study demonstrated that when the TEA analyzer is interfaced to a fused silica capillary column gas chromatograph, it is capable of detecting low picogram levels of nitro-PAH (15). In this paper, the performance of the detector is further evaluated for the determination of nitroPAH in complex environmental samples such as diesel particulates and coal combustion products. EXPERIMENTAL SECTION Equipment. Gas Chromatography f T E A Analyzer (GCf TEA). The gas chromatograph (Model 5840A, Hewlett-Packard, Palo Alto, CA) was equipped with an on-column capillary injector (SGE Scientific, Austin, TX, Model OCI-3). A 30 m X 0.32 mm fused silica SE-54 capillary column (J & W Scientific Inc., Rancho Cordova, CA) was used with a methylphenylvinyl silicone bonded phase and a 0.25 Wm film thickness. The carrier gas was helium at a head pressure of 18 psi. The injection port was maintained
1159
at ambient temperature. The GC oven temperature was programmed at 40 "C to 300 "C at 6 "C/min, with a 5-min hold at 300 "C. Peak areas were obtained with the Hewlett-Packard 5840A GC data terminal. The detector was a TEA Model 610 analyzer (Therm0 Electron Corp., Waltham, MA) operating in the nitro mode. The GC-TEA interface temperature was set at 275 "C, and the pyrolyzer temperature was maintained at 900 "C. The fused silica SE-54 capillary column was coupled directly to the pyrolyzing furnace. The reaction chamber pressure was 1.5 torr. The oxygen flow to the ozonator was 5 mL/min. A stainless steel cold trap was maintained at -120 "C with an ethanol/liquid nitrogen slush bath. Gas ChromatographylMass Spectrometry (GCIMS). Gas chromatography/mass spectrometry was performed on a Finnigan MAT 212 (Finnigan Instrumenta, Sunnyvale, CA) double-focusing mass spectrometer interfaced to a Varian 3700 (Varian Associates, Palo Alto, CA) gas chromatograph fitted with an on-column injector. The mass spectrometer was operated at an electron ionization energy of 70 eV, and the ion source was maintained at 200 "C. Mass range from m l z 45 to 500 was scanned every 3 s at a resolution of 800. The data generated were stored and processed on-line by a Finnigan SS-200 data system. For the separation of the compounds of interest, a 15 m long X 0.32 mm i.d. fused silica SE-54 capillary column having a film thickness of 0.25 Km was used, with helium as the carrier gas. The column head pressure was set at 16 psi, giving a helium flow rate of 1.5 mL/min at 45 "C. As with the GC/TEA, the injection port temprature was ambient. The GC oven temperathe was initially set at 45 OC and then programmed at 4 "C/min to 290 "C and maintained at that temperature until no more peaks were eluted. Chemicals. All solvents used were distilled in glass (Burdick and Jackson Laboratories Inc., Muskegon, MI). Polycyclic aromatic hydrocarbon standards were obtained from Aldrich Chemical Co., Milwaukee, WI, and Chem Service, Inc., West Chester, PA. Amyl nitrate, 1-nitronaphthalene,9-nitroanthracene, 1,5-dinitronaphthalene,and 1,4,54rinitronaphthalenewere obtained from Pfaltz and Bauer, Inc., Stamford, CT. Nitrobenzene, 2-nitronaphthalene, 4-nitrobiphenyl, 2-nitrofluorene, 2,7-dinitrofluorene,and N-nitrosodimethylamine were purchased from Aldrich Chemical Co., while 1-nitropyrene and 3-nitroperylene were supplied by the Chemical Repository, IIT Research Institute, Chicago, IL. Standard solutions were made up in dichloromethane, protected from light, and stored in the refrigerator. Under these conditions, the standards were observed to be stable for a period of up to 4 months, with the exception of 9-nitroanthracene, which was partially transformed into9-anthraquinone. Sample Collection and Preparation. Coal Combustion Product. The sample of coal combustion product was generated from a 700-kW experimental fluidized bed furnace (Energy Laboratory, MIT) utilizing bituminous coal as the fuel. A detailed description of the system has been reported by Beer et al. (19). The sample wm withdrawn from the furnace with a stainless steel probe placed 2.1 m above the air distributor. The sample was collected on a glass fiber filter and a water-cooled XAD-2 trap located downstream of the probe as described earlier (20). The collected sample was then extracted for 24 h with dichloromethane (DCM) at 40 "C in a Soxhlet apparatus. The extract was concentrated to appproximately 10 mL in a rotary evaporator, transferred to a centrifuge tube, and further concentrated to 1 mL under a gentle stream of nitrogen at room temperature. Diesel Exhaust Particulate. A 1978 5.7-L Oldsmobile diesel engine (Energy Laboratory, MIT) was used to generate the diesel soot. The engine was modified such that only one cylinder was functional. The engine exhausts were quenched in a dilution tunnel where a filter was placed at the downstream flow. Soot particulates, collected on the filter, were extracted with 500 mL of dichloromethane at 40 "C for 24 h in a Soxhlet apparatus. The DCM extract was reduced to approximately 5 mL on a rotary evaporator and further concentrated to 1 mL under a gentle stream of nitrogen at room temperature. Alumina Column Chromatography. Column chromatography was performed on a 0.9 cm i.d. glass column packed with 9.5 g of neutral aluminum oxide (E.M. Laboratories, Inc.) having a mesh size of 70-230. It was activated at 120 "C overnight. The gross diesel extract was carefully introduced on top of the packing and eluted successively with 15 mL of hexane, 50 mL of toluene,
1160
ANALYTICAL CHEMISTRY, VOL. 56, NO. 7, JUNE 1984
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Figure 1. Capillary GC/TEA chromatograms of nitro-PAH compounds. The identities of the peaks are as follows: (1) 1-nitronaphthalene;(2) 2-nitronaphthalene; (3) 4-nitroblphenyl; (4) 1,5dinitronaphthalene;(5) 2-nitrofluorene; (6) 9-nitroanthracene; (7) 1,4,5-trinitronaphthalene; (8) I-nitropyrene; (9) 2,7dlnitrofluorene; and (10) 3-nitroperylene. (A) Chromatogram of nitro-PAH standards, of 1 ng each, except (4) 0.7 ng, (6) 1.4'ng, (7) 0.4 ng, (8) 1.2 ng, (9) 1.2 ng, and (10) 2.2 ng. (B) Demonstration of selectivity. Test matrix contained naphthalene, phenanthrene, chrysene, fluorenone, carbazole, dibenzofuran, Isoquinoline, 1-cyanonaphthalene, 2-aminofluorene, dibenzothiophene, benzo[ghi]perylene, 2nltronaphthalene, and I-nitropyrene. Only 2-nitronaphthaleneand 1-nitropyrene,the two nitro-PAH compounds, are seen to produce a response. (C) Capillary GC/TEA chromatogram of diesel extract, with pyrolyzer temperature set at 900 O C . 1-Nitronaphthalene, 2-nitronaphthalene, 2-nitrofluorene, and 1-nitropyreneare tentatively Identified by retention time. An unidentified peak, labeled nitro-252, is also shown. (D) Caplllary GWTEA chromatogram of diesel extract, with pyrolyzer temperature set at 500 O C . Note that the peaks observed in (C) above are not present.
Table I. Detection Limit of Selected Nitro-PAH by Capillary GC/TEA detection limit, pg (S/N = 3) compound 1-nitronaphthalene 2-nitronaphthalene 4-nitrobiphenyl 1,5-dinitronaphthalene 2-nitrofluorene 9-nitroanthracene 1,4,5-trinitronaphthalene 1-nitropyrene 2,7-dinitrofluorene 3-nitroperylene
8 7 7 9 8 10
7 25 7
25
40 mL of chloroform, and 40 mL of methanol.
Reference standards of 1-nitronaphthalene, 2-nitrofluorene, and l-nitropyrene were used to determine the retention behavior of the nitrated PAH. It was found that they eluted in the toluene and chloroform fractions with quantitative recoveries. The two fractions were thus combined and concentrated for chemical characterization.
RESULTS AND DISCUSSION GC/TEA. The separation of a mixture of ten nitro-PAH on the fused silica SE-54 capillary column with the chemilu-
Table 11. Precision of Capillary GC/TEA on Selected Nitro-PAH amt % re1 injected, std dev compound ng (N=6) 1-nitronaphthalene 2-nitronaphthalene 4-nitrobiphenyl 1,5-dinitronaphthalene 2-nitrofluorene 9-nitroanthracene 1,4,5-trinitronaphthalene 1-nitropyrene 2,7-dinitrofluorene 3-nitroperylene
0.50 0.55 0.50 0.35 0.50 0.50 0.20 0.60
0.60 1.1
3.4 4.0
3.8 3.1 3.2 8.6 2.7 4.5 3.0 2.5
minescent detector is shown in Figure 1A. The detection limit (SIN = 3) of nitro-PAH in the GC/TEA system is estimated to be 10-25 pg injected on-column, as shown in Table I for a number of selected nitro-PAH. Precision of the method at the low nanogram level, shown in Table 11, is better than 9% relative standard deviation. In the complex matrices of diesel particulates, coal combustion products, carbon blacks, and air particulates, the number of compounds present is essentially inexhaustible. As analytical methodology and instrumentation improve, addi-
ANALYTICAL CHEMISTRY, VOL. 56, NO. 7, JUNE 1984
tional compounds are reported. Presently, the major classes of compounds that have been identified in these matrices include PAH, their amino, nitro, and carbonyl derivatives, as well as oxygen-, sulfur-,and nitrogen-containing heterocyclics (3, 4,21-25). Although silica gel or alumina column chromatography has been used to fractionate the initial extracts, the "moderately polar" fraction where the nitro-PAH are expected to be eluted also contain oxygenated compounds such as ketones, carboxyaldehydes, acid anhydrides, hydroxy-PAH, and quinones (26). The presence of these compounds complicates the identification of the nitro compounds and renders the interpretation more difficult. In this study, the effect of the presence of these compounds on the nitro-selective detector was evaluated. A mixture of PAH and related compounds, representative of those normally present in diesel exhaust particulates, was prepared with the addition of nitrated PAH. The concentrations of the PAH were 10-fold to that of the nitrated PAH. It was observed that during GC-TEA analysis, only 2-nitronaphthalene and 1-nitropyrene gave a response, as shown in Figure 1B. When the concentrated extract from the pooled toluene and chloroform fractions of the diesel sample was analyzed by GC/TEA, several peaks were observed at the retention times of 1-nitronaphthalene, 24tronaphthalene, 2-nitrofluorene, and 1-nitropyrene, as shown in Figure 1C. The concentrations of these apparent nitro-PAH were determined to be 0.88 ppm, 0.02 ppm, 0.11 ppm, and 2.84 ppm, respectively, based on the original weight of particulate matter. The findings of these nitro-PAH in diesel particulates are in good agreement with the results reported earlier by investigators using other techniques ( 5 , 6 ) . In addition, another TEA responsive peak with a concentration of 1.23ppm was observed which preceded that of 3-nitroperylene. Taking the retention time of 1nitronaphthalene as unity, the relative retention times (RRT) of the unknown peak and 3-nitroperylene are 2.298 and 2.371, respectively. Nishioka et al. (27) recently reported that several mononitro derivatives of PAH where the parent PAH have molecular weight 252 such as the benzopyrenes, perylene, and the benzofluoranthenes could be present in diesel particulates. Under the present GC conditions, the unknown peak eluted 1.2 min before 3-nitroperylene. Because of the unavailability of these nitro-PAH standards, the identity of this peak cannot be positively determined, but it is likely to be a nitro derivative where the parent PAH has a molecular weight 252. In the exhaust emissions of vehicles fueled with methanol/diesel or methanol/gasoline mixture, methyl nitrite was reported to be present at a concentration of up to 5 ppm (28). In diesel crankcase emissions, N-nitrosodimethylamine and N-nitrosomorpholine have been identified (29). In addition, alkyl nitrates, used as cetane improver additives in diesel fuel, were determined to be present in the range of 0.08-0.33 vol % (30). Since the TEA analyzer operates as a nitro/nitroso-specific detector, it is anticipated that these compounds may also register a TEA response. As demonstrated earlier (14),optimal TEA response for compounds containing the C-NO2 group was observed when the catalytic pyrolyzer temperature was maintained at 800 "C or above. At temperatures of 500 "C or below, the responses associated with these compounds were minimal. For N-nitrosamines and nitrate esters, however, a temperature range of 400-500 "C is sufficient for the cleavage of the more labile N-NO or 0-NO2 bond. Thus, to differentiate the nitro-PAH responses from those of N-nitrosamines, alkyl nitrites, and nitrates, the catalytic pyrolyzer temperature can be varied selectively. In the present study, it was observed that when the catalytic pyrolyzer temperature was lowered to 500 "C, the only responses observed were due to N-nitrosodimethylamine, N-
1161
A
SCAN
SCAN
Flgure 2. (A) Mass chromatograms of total ion plot (TI), m l z 115, 127, 143, and 173. (B) Mass chromatograms of total ion plot (TI), mlz 189, 201, 217,
and
247.
nitrosomorpholine, methyl nitrite, and amyl nitrate. For the diesel particulate sample, the peaks observed at the pyrolyzer temperature of 900 "C disappeared when a similar analysis was made at 500 "C, as shown in Figure 1D. Furthermore, the retention characteristics of the nitro-PAH on the capillary GC column are very different from those of nitrites, nitrates, and N-nitrosamines, which were eluted well before l-nitronaphthalene, the smaller two-ring nitro-PAH. Thus, based on GC retention data and pyrolyzer temperature profile, as well as detector selectivity to nitro compounds, the GC/TEA technique should provide a useful tool for the screening of nitro-PAH in the sample. Analysis of the coal combustion extract by GC/TEA did not indicate the presence of nitro-PAH. The extract, however, exhibited mutagenicity in bacterial assays. Detailed chemical characterization by GC/MS revealed that the fraction showing highest mutagenicity contained aromatic ketones, aldehydes, and azaarenes. The results of that study are to be reported elsewhere (31). Gas Chromatography / Mass Spectrometry (GC/ MS). Mass spectrometric analysis of the combined toluene/chloroform fractions indicated the presence of typical PAH compounds generally found in diesel combustion extracts as well as combustion products generated from other sources. These include many parent PAH and their alkylated homologues (32). Phthalates, a possible source of contamination introduced during sample workup, were also found. The 70-eV electron impact mass spectra of nitro-PAH are very distinctive. They usually exhibit parent ions M+ and fragment ions at m / z (M - 30)+,(M - 46)+, and (M - 58)+, corresponding to the cleavage of NO, NOz,and CN02 moieties. Inspection of the EPA-NIH mass spectral database indicated that for nitronaphthalene, the characteristic ions are M+, (M - 46)+, and (M - 58)'. The mass chromatograms of these ions were plotted and they all maximized at scan 377, as shown in Figure 2A. Furthermore, the capillary GC retention characteristics of this peak also matches that of the l-nitronaphthalene standard. When the ma9s chromatograms of M+,(M - 30)+,(M - 46)+,
ANALYTICAL CHEMISTRY, VOL. 56, NO. 7, JUNE 1984
1162
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LITERATURE CITED
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and (M - 58)’ ions were plotted for other nitro-PAH, an isomer of nitrofluoranthene or nitropyrene was identified. This is shown in Figure 2B where the mass chromatograms of these four ions maximized at the same point (scan 675). After background substraction from scan 673, the mass spectrum of scan 675 is shown in Figure 3. The distinctive ions with m / z 247, 217,201, and 189 are indicative of nitropyrene or nitrofluoranthene. On the basis of capillary GC retention data with authentic standards and published data, this compound is identified as 1-nitropyrene. Mass chromatograms of dinitropyrenes, nitroperylene, and nitrobenzopyrene/nitrobenzofluoranthenewere also plotted for the TEA peak eluting before 3-nitroperylene, but no peak was detected, even a t the maximum sensitivity of the mass spectrometer. It is estimated that under the current conditions the detection limit of GC/MS is in the range of 1-10 ng for 1-nitropyrene, while that of GC/TEA is in the order of 25 pg. It appeared that the unknown peak observed in GC/TEA was present at too low a level to be confirmed by GC/MS. As an aid to characterize the GC peaks from chromatographic analysis where compounds of homologous series are anticipated to be present, but authentic standards are not readily available for comparison, a number of investigators have devised a scheme based on the relationship between retention index and molecular connectivity. For PAH compounds, this linear relationship has worked quite well in identifying unknown resolved components (33,34). As for nitro-PAH, a similar scheme can also be developed. Preliminary studies of 53 nitro-PAH (35)showed that there is indeed a close correlation between those parameters for this class of compounds. When the full library of data is compiled, this can provide useful information to the analyst. Coupled to the nitrosyl-specific TEA analyzer, it is anticipated that the positive characterization of the nitro-PAH in complex matrices will be greatly enhanced.
ACKNOWLEDGMENT We thank A. Lafleur and J. Buckley for many valuable discussions. We also thank A. Robbat, Jr., for making a copy of his manuscript available to us prior to publication.
Jager, J. J . Chromatogr. 1978, 152, 575. Rosenkranz, H. S.;McCoy, G. C.; Sanders, D. R.; Butler, M.; Klrlazldes, D. K.; Mermelsteln, R. Science 1980, 209, 1039. Newton, D. L.; Erickson, M. D.; Tomer, K. B.; Pellizzarl, E. D.; Gentry, P.; Zweldlnger, R. B. Envlron. Scl. Technol. 1982, 16, 206. Ramdahl, Th.; Becher, G.; Bjorseth, A. Envlron. Sci. Technol. 1982, 16, 861. Rappaport, S. M.; Jln, 2. L.; Xu, X. B. J. Chromatogr. 1982, 240, 145. Schuetzle, D.; Riley, T. L.; Prater, T. J.; Harvey, T. M.; Hunt, D. H. Anal. Chem. 1982, 5 4 , 265. Nlelsen, T.; Ramdahl. T.; Bjorseth, A. EHT, Envlron. Health Perspect. 1983, 4 7 , 103. Pltts, J. N., Jr. EHP, Envlron. Health Perspect. 1983, 4 7 , 115. Campbell, J.; Crumplln, G. C.; Garner, J. V.; Garner, R. C.; Martln, C. N.; Rutter, A. Carclnogenesls 1981, 2 , 559. Pms, J. N., Jr.; Lokensgard, D. M.; Harger, W.; Fisher, T. S.; Mejla, V.; Schuler, J. J.; Scorziell, G. M.; Katzensteln, Y. A. Mutat. Res. 1982, 103, 241. Ohgakl, H.; Matsukura, N.; Morino, K.; Kawachl, T.; Sugimura, T.; Morita, K.; Tokiwa, H.; Hlrota, T. Cancer Lett. 1982, 15, 1. Jin, 2. L.; Xu, X. 8.; Nachtman, J. P.; Wel, E. T. Cancer Lett. 1982, 15, 209. Phillips, J. H.; Coraor, R. J., Prescott, S. R. Anal. Chem. 1983, 55, 889. Lafleur, A. L.; Mllls. K. M. Anal. Chem. 1981, 53, 1202. Yu, W. C. I n “Polynuclear Aromatlc Hydrocarbons: Formatlon, Metabolism, and Measurement”; Cooke, M., Dennis, A. J., Eds.; Battelle Press: Columbus, OH, 1983; pp 1267-1279. Wolf, M. H.; Yu, W. C.; Flne, D. H. I n “Analytlcal Methods for Pesticides and Plant Growth Regulators”; Zweig, G., Sherma, J., Eds. Academic Press: New York, 1980; pp 363-387. Hotchklss, J. H. J . Assoc. Off. Anal. Chem. 1981, 64, 1037. Flne, D. H.; Yu, W. C.; Goff, E. U.; Bender, E.; Reutter, D. J . Forenslc Scl. 1984, 2 9 , (3). Beer, J. M.; Sarofim, A. F.; Sandhu, S. S.; Andre, M.; Bachouchln, D.; Chan, L. K.; Chuang, T. 2.; Sprouse, A. M. U.S.E.P.A. Flnal Report, No. R804978020, 1981. Chlu, K. S.; Walsh, P. M.; Beer, J. M.; Biemann, K. “Proceedlngs, Seventh lnternatlonal Symposium on Polynuclear Aromatlc Hydrocarbons”; Battelle Press: Columbus, OH., 1983; pp 319-339. Later, D. W.; Lee. M. L.; Wilson, B. W. Anal. Chem. 1982, 5 4 , 117. Choudhury, D. R. Envlron. Scl. Technol. 1982, 16, 102. Konlg, J.; Balfanz, E.; Funcke, W.; Romanowskl, T. Anal. Chem. 1983, 55 599. Wllley, C.; Iwao, M.; Castle, R.; Lee, M. L. Anal. Chem. 1981, 53, 400. Clupek, J. D.; Zakett, D.; Cooks, R. G.; Wood, K. V. Anal. Chem. 1982, 54, 2215. Schuetzle, D. EHP, Envlron. Health Perspect. 1983, 47, 65. Nlshloka, M. G.; Peterson, B. A.; Lewtas, J. “Proceedlngs, Sixth International Symposium on Polynuclear Aromatic Hydrocarbons”; Battelle Press; Columbus, OH, 1982; pp 603-613. Jonsson, A.; Bertllsson, B. M. Envlron. Scl. Technol. 1982, 16, 106. Goff, E. U.; Coombs, J. R.; Flne, D. H.; Baines, T. Anal. Chem. 1980, 52, 1833. Schabron, J. F.; Fuller, M. P. Anal. Chem. 1982, 5 4 , 2599. Chlu, K. S.; Llber, H. L.; Walsh, P. M.; Yu, W. C.; Beer, J. M.; Biemann, K., to be submitted for publlcatlon In Mutaf Res. Chlu, K. S. Ph.D. Thesis, Massachusetts Instltute of Technology, Cambridge, MA, 1963. Lao, R. C.; Lee, W.; Thomas, R. S. “Proceedings, Fifth International Symposlum on Polynuclear Aromatic Hydrocarbons”; Battelle Press: Columbus, OH, 1981; pp 407-416. Vassllaros. D. L.: Kona, R. C.; Later, D. W.; Lee, M. L. J. Chromafogr. 1982, 252. 1. Robbat, A., Jr.; Hoes, R. M.; Wouldenberg, T.; White, C. M. Anal. ~ h z m .In , press.
.
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RECEIVED for review October 17,1983. Resubmitted February 21,1984. Accepted February 21,1984. This work was supported in part by grants from the National Institute of Environmental Health Sciences (5 P30 ES02109 and 2 PO1 ES01640).
