Environ. Scl. Technol. 1900, 22, 71-76
Determination of Byproduct Polychlorobiphenyls in Commercial Products and Wastes by High-Resolution Gas Chromatography/Electron Impact Mass Spectrometry+ Mitchell D. ErIckson,* John S. Stanley,* J. Kay Turman, and John E. Going Midwest Research Institute, Kansas City, Missouri 641 10
David P. Redford and Daniel T. Heggem Field Studies Branch, Exposure Evaluation Division, Office of Toxic Substances, U S . Environmental Protection Agency, Washington, D.C. 20460
rn A gas chromatography/electron impact mass spectrometry (GC/EIMS) method for the determination of byproduct polychlorobiphenyls (PCBs) measures the recovery of four 13C-labeled PCBs to assure adequate recovery of the native PCBs from diverse matrices. Byproduct (i.e., non-Aroclor) PCBs differ from most other PCB mixtures in that no recognizable chromatographic pattern can be anticipated. In addition, many matrices may contain similar chlorinated organics. Since diverse sample matrices must be analyzed, various appropriate extraction/cleanup techniques must be applied to each matrix. A set of four 13C-labeledPCBs are employed as recovery surrogates. If the surrogates are recovered and other quality control (QC) parameters are within acceptable limits, then the data may be considered valid. Application to several products and wastes illustrates the flexibility and reliability of the method. Introduction Polychlorinated biphenyls (PCBs) are a chemical class of 209 congeners that generally occur in complex mixtures in a complex, interfering matrix for which a complete set of standards is inaccessible and yet are often to be reported in aggregate concentrations. The task of analyzing becomes more challenging as the complexity of the matrix, the number of analytes, or the number of different matrices increases. Complex analyte mixtures such as PCBs can confound the analyst because of incomplete chromatographic resolution, lack of available standards, similar spectra, and other problems (I). In addition, methods must often be applicable to a general matrix class such as “food” or “solid waste” or to a variable, complex matrix such as sediment, oil, or tissue. The design of analytical methods for determination of byproduct PCBs in commercial products and wastes is a challenging task. An analytical method that is applicable to these complex situations requires a different approach than one for a single analyte in a specified matrix, where all steps, reagents, and apparatus may be specified. The method must be flexible enough to fit the potential analyte/matrix combinations and still yield reliable results. Since many analyte/matrix combinations may be a one of a kind analysis, a lengthy method development and validation sequence would be costly and require too much time. ‘Presented in part at the Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, March 7-13, 1983, Atlantic City, NJ,and at the Symposium on Advances in Analytical Methods for Monitoring Organic Chemicals in the Environment-Water and Hazardous Wastes, October 16-18, 1984, Cincinnati, OH. *Present address: Argonne National Laboratory, Argonne, IL 60439. 00 13-936X/88/0922-007 1$0 1.50/0
0 1987 American
Traditional analytical methods for PCBs have circumvented the problem of complexity of the analyte and inaccessibility of standards by using standards of the commercial mixtures (e.g., Aroclors) from which the sample analytes were thought to be derived. Recently, concern has developed over PCBs that are synthesized as byproducts in commercial products or product waste. In samples encountered thus far, these analytes range from only one congener to over 80 (2). The analyte matrix may be a solid, liquid, or gas and may be of any purity. Product examples that may have byproduct PCBs include chlorophenylsilane adhesives, technical tetrachlorobenzene, tear gas (chlorinated acetophenone), phthalocyanine pigments, chlorinated paraffins, chlorinated phenols, and phenolic resins. Product waste examples include chlorinated aromatic still bottoms, tetrachloroethylene production waste, asphaltenes, and used solvents. Under the Toxic Substances Control Act (TSCA, Public Law 94-469, October 11, 1976), the US. Environmental Protection Agency (EPA) regulates PCBs that are generated as byproducts in the manufacture of commercial products. As part of the regulatory rules ( 3 , 4 ) ,the EPA has specified the analytical method that will be used to determine compliance (5). The original method (5) has been revised (6-8),and the development and application of this method are presented here.
Materials and Methods Source of Standards. Seventy-seven PCB congeners were acquired from Ultra Scientific, Inc., Hope, RI, and Analabs, North Haven, CT. The purity of these congeners and their identity as the correct PCB homologue were verified by high-resolution fused-silica capillary column gas chromatography/electron impact mass spectrometry (HRGC/EIMS). The internal standard [2H6]-3,3’,4,4’-tetrachlorobiphenyl was purchased from KOR Isotopes, Inc., Cambridge, MA. [Note: This compound may not be currently available; other appropriate internal standards may be substituted.] The purity (-95%) and identity of the internal standard were verified by HRGC/EIMS. The major contaminant was a deuteriated aminotrichlorobiphenyl. The custom synthesis of the recovery surrogates, [1’,2’,3’,4’,5’,6’-13C6]-4-chlorobiphenyl, [l3CI2]-3,3’,4,4’tetrachlorobiphenyl, [‘3C12]-2,2’,3,3’,5,5’,6,6’-octachlorobiphenyl, and [13C12]decachlorobiphenyl, has been reported elsewhere (9, IO). The chemical purity of each product was determined by both packed column gas chromatography/flame ionization detection and HRGC/EIMS to be 298%. The mass spectrum of each product wae consistent with a 13C isotopic purity 199%. Solutions of these recovery surrogates may be requested from Toxic and Hazardous Materials Repository, Environmental Moni-
Chemical Society
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Table I. HRGC/EIMS Retention Times and Response Factors for Individual PCBs”
homologue
no. of isomers measured
no. of possible isomers
response factorsb obsd relative retention timesb
mean
0.40-0.50 0.52-0.69 0.62-0.79 0.72-1.01 0.82-1.08 0.93-1.20 1.09-1.30 1.19-1.36 1.31-1.42 1.44
2.742 2.048 1.592 0.946 0.739 0.500 0.308 0.224 0.188 0.179
3 12 24 42 46 42 24 12 3 1
quadrupoleC SD RSD, %d 0.254 0.322 0.289 0.189 0.130 0.096 0.025 0.039 0.030
9.3 15.7 18.1 20.0 17.6 19.1 8.0
17.3 16.2
mean 2.329 1.663 1.167 0.903 0.751 0.640 0.497 0.463 0.467 0.586
magnetic sectorc SD RSD, % 0.199 0.229 0.248 0.130 0.135 0.124 0.060 0.071 0.105
8.5 13.8 21.2 13.2 18.0 19.3 12.0 15.4 22.5
‘Individual response factors given in ref 5 and 11. bRelative to [2H6]-3,3/,4,4’-tetrachIorobiphenyl. osingle measurement for each congener; all data collected on a single day to minimize instrumental effects. dRelative standard deviation.
Table 11. Pairings of Analyte, Calibration, and Surrogate PCBs analyte compound
congener” 1 2, 3 4-15 16-39 40-81 82-127 128-169 170-193 194-205 206-208 209
2-ClzHgCl 3- and 4-ClzHgC1
calibration standard congener compound 1
congener
surrogate compound
n
L 211 4 211 211 2,4 C1ZH6C12 212 2,4,6 C12H7C13 2,2’,4,6 212 C12H6C14 212 2,2’,3’,4,5 C12H6C16 212 2,2’,3,4,5,6’ C12H4C16 2,2’,3’,4,4’,5’,6 213 C1ZH3C17 213 2,2’,3,3’,5,5’,6,6’ C12HZC1, 2,2’,3,3’,4,4’,5,6,6’ 213 C1zHCle 214 ClZCllO C12C110 a IUPAC numbering system, see ref 11 and 31. bSecond monochlorobiphenyl subsequently dropped from calibration mixture; all three mono isomers are auantitated with 2-monochlorobiahenvl.
3 7 30 50 97 143 183 202 207 209
toring and Support Laboratory, U.S.Environmental Protection Agency, 26 w. St. Clair Street, Cincinnati, OH 45268. Instrumentation. Samples were analyzed on a Finnigan 4023 quadrupole system operated in the electron impact mode at 70-eV electron energy and interfaced to an Incos 2400 data system. The quadrupole system was tuned with decafluorotriphenylphosphine. A high-resolution fused-silica capillary column (Durabond DB-5, 15 m, 0.255 mm id., 0.25-km film thickness; J&W Scientific, Rancho Cordova, CA) was routed directly into the ion source. The column was held at 110 OC for 2 min, then programmed at 10 deg/min to 325 OC, and held. The helium carrier gas flow velocity was 45 cm/s. A J&W on-column injector was used. The mass spectrometer was scanned over limited mass ranges for the analysis of PCBs by homologue. These were as follows (homologueor degree of chlorination in parentheses): 186-190 (mono), 192-196 ([13C]mono),220-226 (di), 254-260 (tri), 288-306 (tetra, [2H6]tetra,and [13C]tetra), 322-328 (penta), 356-364 (hexa), 386-400 (hepta), 426-434 (octa), 438-446 ([13C]octa), 460-468 (nona), 494-504 (deca), and 506-516 ([13C]deca)amu. Qualitative Data Interpretation. Retention time windows (Table I) were established from the retention times of 77 congeners and a mixture of Aroclors 1016,1254, and 1260 (4, 10). Criteria for identification of a chromatographic peak as a PCB required elution within the established retention time window and coincident response of characteristic ions from the molecule cluster. A latitude of &20% of the ion ratios measured with standards was allowed. As additional confirmation, higher mass windows, in particular M 70, were searched to prevent misiden-
+
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tification of a PCB fragment ion cluster as the parent. Quantitative Data Interpretation. PCBs were quantitated by homologue according to response factors and the internal standard method. Calibration solutions (Table 11) containing 11 congeners (two monochlorobiphenyls and one each of the other homologues), the C122H6C14internal standard, and the four 13C-labeled surrogates were used for response factor determinations (5, 11). Each isomer was selected as representative of a homologue on the basis of measurements of the 77 available congeners (Table I). Specifically,the response factors for each of the individual 77 PCB congeners were measured relative to the C12H6C1,. The response factors for isomers within a specific homologue or degree of chlorination were averaged. The individual isomer that exhibited a response factor nearest the average response factors was selected for the calibrated standard for each homologue. A detailed discussion of the measurement of response factors and the selection of the specific isomers is presented elsewhere (5, 11). Concurrent with this work, Gebhart et al. (12)selected a similar set of calibration compounds (i.e., one congener per each degree of chlorination). Although the experimental procedures and selection criteria were similar, many of the compounds chosen for use as calibrants were different from those chosen in the work described here. The calibration congeners selected by Gebhart et al. were incorporated into another EPA method (13). The relative concentrations of the congeners increased with the degree of chlorination to give similar peak intensities across the chromatogram. This was necessary due to the inherent decrease in response of PCBs and other organic compounds with substitution of chlorine for hydrogen. Concentrations ranged from 10-1000 pg/pL for
monochlorobiphenyl to 50-5000 pg/pL for the higher homologues. All peaks for a homologue were quantitated and summed, and the surrogate recovery correction was applied to yield a corrected amount. Selection of Techniques. An extensive literature review was conducted as a basis for selection of applicable techniques (14). Although hundreds of references addressed PCB analysis, only a few mentioned the analysis of byproduct PCBs (2,15-18). All others addressed the analysis of commercially derived (i.e., Aroclor-type) PCB mixtures. Most previous workers had chosen to use GC/MS for byproduct PCB analysis (2,15-17), although some success was reported for analysis of a specific chlorinated benzene waste with GC/electron capture detection (18). Because of the complexity of the commercial products and the associated waste stream, GC/MS was judged to be the best instrumental technique that could be applied universally for byproduct PCBs. The electron impact ionization mode was chosen for several reasons. It is more widely used than other ionization modes and is available on most mass spectrometers. The response factors are relatively consistent among isomers of a given degree of chlorination (11,19),making possible the selection of a single congener for calibration for each homologue. The use of positive chemical ionization (11,20) and negative chemical ionization (11,17,21) has also been applied to PCB analysis. Negative chemical ionization has the distinct advantage of sensitivity for the more highly chlorinated homologues (17,21). However, the marked effects (21) of the reagent gas composition and pressure on the ionization (and thus the response factor) made chemical ionization a less attractive choice for the method described here. This method relies heavily on the measurement of recoveries of the four 13C-labeledPCBs to assess recovery (i.e., accuracy) of the native PCBs through the extraction and cleanup steps, which must be tailored to the specific matrix at hand. While other compounds (e.g., fluorobromobiphenyls) could prove satisfactory as recovery surrogates, mass labeled PCBs represent the best choice since they will behave the same as natural abundance PCBs in any extraction or cleanup. The use of recovery surrogates is relatively common in other areas such as "dioxin" analysis (22,23) and has also been applied to the determination of commercial PCB mixtures in oil (24) with the surrogates synthesized for this program (9, 10). On the basis of the literature review (14),consultation with other researchers, and the analytical needs under TSCA, a method for analysis of byproduct chlorinated biphenyls in commercial products and wastes was developed. The method allows the analyst to select many of the analytical steps on the basis of his or her own experience, while insuring the integrity of the results with a stringent quality control (QC) program. The rationale for selection of this method has been presented in detail (14, 25).
During the development of this method, additional validation of the use of the four 13C-labeledPCBs used in this study was conducted by another laboratory. Their results (26) indicate that the use of multiple 13C-labeled surrogates improves analytical precision and accuracy relative to a single internal standard. Their work did not use the surrogates to monitor recovery through laboratory preparation steps. Methods. The method has been presented in full detail elsewhere (5-8) and is summarized here. The process or product must be sampled such that the specimen collected for analysis is representative of the whole. Statistically
designed or otherwise defensible selection of the sampling position, time, or discrete product units should be employed. The sample must be preserved to prevent PCB loss prior to analysis. The sample is mechanically homogenized and subsampled if necessary. The sample is then spiked with the four 13C-labeledPCB surrogates, and the surrogates are incorporated by further mechanical agitation. The surrogate-spiked sample is extracted and cleaned up at the discretion of the analyst. Simple dilution or direct injection is permissible. Possible extraction techniques (27) include liquid-liquid partition, thermal desorption, and sorption onto resin columns followed by solvent desorption. Cleanup techniques may include liquid-liquid partition, sulfuric acid cleanup, saponification, adsorption chromatography, gel permeation chromatography, or a combination of cleanup techniques. The sample is diluted or concentrated to a final known volume for instrumental determination. The PCB content of the sample extract is determined by high-resolution (preferred) or packed column gas chromatography/electron impact mass spectrometry (HRGC/EIMS or PGC/EIMS) operated in full-scan, selected ion monitoring (SIM), or limited mass scan (LMS) mode. PCBs are identified by comparison of their retention times and mass spectral intensity ratios to those in calibration standards. Native and 13C-labeledPCBs are quantitated against the response factors for a mixture of 10 unlabeled PCB congeners and four 13C-labeledrecovery surrogates. The second monochlorobiphenyl (congener 3; see Table 11) was deleted from the solution in the later revisions of the method (6-8) since an initially observed high response factor for 2-chlorobiphenyl was anomalous. The PCBs may be optionally confirmed by full-scan HRGC/EIMS (if SIM or LMS techniques were used), retention on alternate GC columns, other mass spectrometric techniques, infrared spectrometry, or other techniques provided that the sensitivity and selectivity of the confirmatory technique are demonstrated to be comparable or superior to GC/EIMS. Appropriate QC procedures are included to assess the performance of the analyst and the quality of the results. These QC procedures include instrumental performance criteria, data reduction checks, and the analysis of blanks, replicates, and standard addition samples. Acceptable performance for the QC measures must be defined in a quality assurance CQA) plan (28) approved by the client or data user. For surrogates, a typically acceptable recovery is 50-150%. Chloride isotope ion ratios for both surrogates and native PCBs should be *20% of that observed for standards.
Results The applicability and utility of the method has been demonstrated by measurement of unlabeled and labeled PCB recoveries with various column cleanups and also application to several real-world matrices. These matrices cover a broad range of industrial products that may contain PCBs as byproducts of manufacture. Recovery Using Selected Cleanup Techniques. The recovery of the 11 calibration congeners and three of the 13C-labeledsurrogates from solvent using five common cleanup techniques (11,27) was measured, as is shown in Table 111. The recoveries of the labeled and unlabeled compounds agree well, supporting the assumption that the 13C-labeledPCBs can be used to assess extraction/cleanup recovery. For example, the average recovery of the PCB congeners was 86% as compared to 83% for the four 13Clabeled surrogates when taken through a concentrated Environ. Sci. Technol., Vol. 22, No. 1, 1988
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Table 111. Recovery of PCBs Using Selected Cleanup Techniques
cleanup techniquesC sulfuric acid Florisil column Florisil slurry alcoholic KOH alumina column
1
Dichlorobiphenyls
13C-labeled unlabeled PCBs" PCBsb mean mean no. of recovery, recovery, replicates % RSDd % RSDd 1 2 2 2 2
86 68 86 79 70
9 9 7 11 9
83 60 91 80 71
13 21 12
9 14
"The 11 congeners listed in Table I as components of the calibration standard were spiked into hexane (0.5-2.1 pg/sample) and submitted to the cleanup technique. The recovery reported is the mean of the individual or duplicate recoveries for the 11 congeners. 13C-Labeledmono-, tetra-, and decachlorobiphenyls spiked at 2.6, 5.3, and 10.2 pg/sample, respectively. [13C]Octachlorobiphenyl was not available a t the time these experiments were conducted. See ref 4 for procedural details. dRelative standard deviation.
sulfuric acid cleanup procedure. The data indicate that overall the relative percent deviation between recoveries of the unlabeled versus labeled PCBs ranged from 1% for the alcoholic KOH cleanup to 12% for the Florisil column procedure. Interestingly, the two lowest recoveries are for column cleanup techniques that were used as published. With both the Florisil and alumina column cleanups, the recoveries of the lower homologues were lower than those for the higher homologues. This may be a result of column selectivity for the lower homologues. Application to a Chlorinated Benzene Waste Stream Sample. A clear, nonviscous liquid sample labeled "chlorinated benzene waste stream" was analyzed by several cleanup techniques (Table IV). The sample was extremely complex (Figure l),containing high levels (several percent) of chlorinated benzenes and lower concentrations of many other chlorinated compounds. As shown in Figure 1,many isomers at each each degree of chlorination were identified. By simple dilution and analysis, the surrogate recoveries were acceptable (71-103%). The native PCB quantitations for the simple dilution samples (Table IV) were in good agreement with
TIme (m n)
Figure 1. Reconstructed ion chromatogram of HRGC/EIMS analysis of a chlorinated benzene waste sample. PCBs elute between 12 (mono) and 26 min (deca). Expanded ion plots for di- and hexachlorobiphenyl are shown. Shaded peaks denote those identified as PCBs.
the average reported values for this sample from a previous interlaboratory validation study (2,17,18). The application of various cleanup techniques to this sample was, however, unsuccessful. Not only were the surrogate recoveries erratic, but also the analyte concentrations were much different from and generally lower than those found in the simple dilution samples. With the >50% recovery criteria suggested for the method (5-8), none of these results pass QC and therefore are not reported. Application to C1 and Cz Halocarbon Samples. Table IV shows that no native PCBs were detected in several halocarbon solvent process and product samples, while mono- and dichlorobiphenyls were detected in three of five vinyl chloride process waste samples. The carbon tetrachloride and chlorofluorocarbon solvent samples were prepared by rotary evaporation to concentrate the sample from 500 g to 1mL. A standard addition sample yielded 120 f 18% recovery of 11 PCB congeners spiked at 0.02-0.1 pg/g. The limits of detection were estimated to be less than 0.002 pg/g. Rotary evaporation of four tetrachloroethylene/hexachloroethane samples produced a precipitate during the concentration step. Therefore, these samples were ana-
Table IV. PCBs in Halocarbon Products a n d Wastes chlorinated benzene waste stream" homologue concn., pg/g monochlorobiphenyl dichlorobiphenyl trichlorobiphenyl tetrachlorobiphenyl pentachlorobiphenyl hexachlorobiphenyl heptachlorobiphenyl octachlorobiphenyl nonachlorobiphenyl decachlorobiphenyl total surrogate recovery, % ['3C6]monochlorobiphenyl
[13C12]tetrachlorobiphenyl [ '3C12]octachlorobiphenyl [ 13C12]decachlorobiphenyl
31 (19) 50 (32) 40 (43) 42 (38) 35 (23) 34 (41) 38 (82) 2 (100)
2 (50) 13 (38) 290 (34) 85 (15)c 100 (5)C 71 (4)e 103 (45)'
technical CC1, fluorocarbon and still bottomsd (no. 2)
cZc14/cZc16
CZC14 still bottoms" (no. 1)
NDf ND ND ND ND ND ND ND ND ND ND
ND ND ND ND ND ND ND ND 6 92 98
ND ND ND ND ND ND ND ND ND ND ND
115 (11) 98 (2)
NCB 103 NA~ 133
64 (68Ih 85 (19) 160 (10) 120 (15)
process samples and productsb
99 (11)
101 (10)
vinyl chloride monomer process wastee ND-10 ND-27
ND ND ND ND ND ND
ND ND ND-33
110 (16)' 88 (11) 142 (13) 120 (13)
" Mean of seven replicates prepared and analyzed over a 2-month span; relative standard deviation (RSD) in parentheses. *Mean of six samples; relative standard deviation (RSD) in parentheses. Single sample, analyzed twice, Mean of eight samples; RSD in parentheses. eRange of values in five samples, f ND = not detected. g Not calculated because of interferences. [13C]Monochlorobiphenyl not detected in two samples, probably because of loss in solvent evaporations; recovery counted as zero in summary statistics. 'Mean of seven determiwas not available when this sample was analyzed. nations: RSD in aarentheses. Not analyzed: [13C~octachlorobiphenyl 74
Environ. Sci. Technol., Vol. 22, No. 1, 1988
lyzed with no preparation except surrogate addition. Triplicate analyses of a standard addition sample spiked with 11 congeners at 0.05-0.1 pg/g yielded 98 f 4% average recovery. The C2C14still bottoms sample 1 was a black liquid containing 6% sand and other inorganic solids. According to the client, the sample was 53% C2C1,, 11%CC4, and minor amounts of other chlorinated aliphatic and aromatic compounds. Heptane (0.22%) was the only nonhalogenated organic listed. The sample was mixed, aliquoted, spiked with the W-labeled recovery surrogates, diluted, and filtered to remove the sand prior to the HRGC/EIMS analysis. All three nonachlorobiphenyls and the decachlorobiphenyl were found in this sample at a total concentration of 98 pg/g (Table IV). Interferences in the [13C]monochlorobiphenylion channels prevented quantitation of the recovery of this surrogate. The native monothrough trichlorobiphenyls were not detected in this sample; had there been quantitatable levels, the level of surrogate recovery data would have cast doubt on the validity of the native concentrations and additional work would have had to be done to obtain valid results. The sample of still bottoms from another tetrachloroethylene process (no. 2 in Table IV) was a black viscous liquid with solids present. Aliquots (-1 g) were spiked with surrogates, diluted with 3 mL of hexane, and mixed. The solids were separated by centrifugation, the hexane layer was decanted, and the extraction was repeated twice more. The concentration hexane extracts precipitated a white material identified by GC/MS as hexachloroethane. The precipitates were removed by filtration. Further cleanup was deemed necessary since the extracts were yellow, continued to precipitate hexachloroethane,and had a high background as determined from screening analyses by GC/FID. Therefore, a 200-pL (1/5) aliquot of each sample was cleaned up by high-performance liquid chromatography (HPLC) (29), using hexane to elute the PCBs through a Waters pBondapack NH2 column (3.9 X 3.00 mm). A fraction previously shown to contain monothrough decachlorobiphenyls was collected, concentrated, and submitted for GC/MS analysis. As shown in Table IV, the surrogate recoveries indicated no substantial loss of PCBs except for the [ 13C]monochlorobiphenyl,which was apparently lost from two samples during the solvent evaporation step. No native PCBs were detected. The vinyl chloride monomer production wastes were black, opaque samples, ranging from nonviscous liquids to chunky semisolids. These samples were prepared by extraction and HPLC cleanup as described above for the carbon tetrachloride and chlorofluorocarbon still bottoms. As shown in Table IV, three of the five process samples contained detectable mono- and dichlorobiphenyls, with total PCB concentrations up to 33 pg/g. Discussion Determination of PCBs synthesized as byproducts in commercial products or product wastes presents three special problems: (a) the analyte does not generally resemble a commercial PCB mixture, so quantitation against Aroclor standards would be incorrect; (b) the sample matrix often contains high concentrations of other chlorinated organics that are not easily removed during a cleanup procedure and that interfere with the qualitative and quantitative analyses; (c) the matrix is undefined and can include gases, liquids, or solids of any purity and complexity. In this situation, analytical methods require a different philosophy than the classic approach for a single analyte in a defined matrix where all steps, reagents, and apparatus
are specified. The method proposed here leaves the choice of many of the analytical steps to the analyst while insuring the reliability of the results with stringent QC measures. Thus, an analyst with experience in general analytical techniques for a product may readily adapt in-house extractionlcleanup procedures to byproduct PCB analysis. Even when the recoveries are not optimized, the I3C-labeled surrogate recoveries will mimic those of the analyte PCBs. As long as the 13C-labeledrecovery surrogates are thoroughly incorporated, their recoveries can be used to assess the data quality. Four 13C-labeledPCBs spanning the homologue range were selected as recovery surrogates. The choice of isomer was based on reaction yield, simplicity, and unambiguity of the synthesis. Although more isotopically labeled surrogates would be preferable (e.g., one for each homologue), the four used in this program were selected as a cost-effective compromise. The selection of the specific compounds appear to be appropriate with the possible exception of the [13C12]-3,3’,4,4’-tetrachlorobiphenyl. Because of the lack of ortho chlorines, this compound behaves differently from most PCBs in several liquid chromatographic column cleanups (11,29). Several of the analyses presented above illustrate the importance of the recovery surrogates in quality control. Many of the cleanup techniques employed are common methods that have been validated for PCB analysis in other matrices without the Wlabeled surrogate data. Analyses of this type without recovery surrogates may have been used by a routine analysis laboratory and erroneous results reported. The complexity of the matrices and the high probability of chlorinated organic interferents preclude the use of GC/ECD. The best available technique for universal application to commercial products and associated waste is GC/EIMS (14). During the validation work, the anticipated difficulty of qualitative and quantitative data interpretation was confirmed. In addition to the inherent problems resulting from extrapolation from 11standards to 209 analytes, interpretation of the complex peak clusters is tedious. The volume of data for one sample is staggering: in one analysis of the chlorinated aromatic waste, 286 peaks were identified and integrated in the PCB mass chromatograms. Of these, 58 peaks met the qualitative criteria and were identified as PCBs. Clearly, different analysts will obtain different results for those peaks that marginally fit the qualitative criteria. In addition, it should be noted that, for many of the samples analyzed in this study, the data interpretation is more time-consuming than the rest of the analytical process. Acknowledgments Robert Fensterheim (Chemical Manufacturers ASSOC., Washington, DC), Kent Hodges (Dow Chemical Co., Midland, MI), and Thomas Robinson (Vulcan Materials Co., Birmingham, AL) are thanked for providing the chlorinated aromatic waste samples. Registry No. Cl2H9Cl, 27323-18-8; C12HsC12,25512-42-9; Cl&C13,25323-68-6; C12H&14,26914-33-0; C12H5C15, 25429-29-2; ClzHdC&,26601-64-9;C12H,Cl,, 28655-71-2; C,2HzClB, 55722-26-4; CiZHCle, 53742-07-7; C&l1o, 2051-24-3; PhC1, 108-90-7; HZC= CHCl, 75-01-4; C13CCCl,, 67-72-1; CCld, 56-23-5;HzS04, 7664-93-9; KOH, 1310-58-3;tetrachloroethane, 25322-20-7;Florisil, 1343-88-0; alumina, 1344-28-1.
Literature Cited (1) Alford-Stevens, Ann L. Enuiron. Sci. Technol. 1987, 21, 137-139. Environ. Scl. Technol., Vol. 22, No. 1, 1988
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(2) Hodges, Kent L.; Robinson, Thomas, A.; Hensler, Charles, J.; Kaley, Robert S.; Caspers, Horst; Ewald, Fred; Pittaway, Alan R. In Recent Advances in Exposure, Health and Environmental Effects Studies of PCBs; Davenport, R. J., Bernard, B. K., Eds.; Office of Toxic Substances, U.S. Environmental Protection Agency: Washington, DC, Dec 1983; LSI-TR-507-137B, NTIS PB84-135771, pp 137-181. (3) Fed. Reg. 1982, 47, 46980-46996. (4) Fed. Reg. 1984,49,28154-28209. (5) Erickson, Mitchell D.; Stanley, John S.; Radolovich, Gil; Turman, J. Kay; Bauer, Karin; Onstot, Jon; Rose, Donna; Wickham, Margaret Analytical Methods for By-product PCBs-Initial Validation and Interim Methods; Office of Toxic Substances, U.S.Environmental Protection Agency: Washington, DC, 1982; EPA-560/5-82-006, NTIS PB83 127 696, 243 p. (6) Erickson, Mitchell D. Analytical Method: The Analysis of By-product Chlorinated Biphenyls in Commercial Products and Product Wastes, Revision 2; Office of Toxic Substances, U.S. Environmental Protection Agency: Washington, DC, 1985; EPA-560/5-85-010, NTIS PB86 109089. (7) Erickson, Mitchell D. Analytical Method: The Analysis of By-product Chlorinated Biphenyls in Air, Revision 2; Office of Toxic Substances, U.S.Environmental Protection Agency: Washington, DC, 1985; EPA-560/5-85-011, NTIS PB86 109097. (8) Erickson, Mitchell D. Analytical Method: The Analysis of By-product Chlorinated Biphenyls in Water, Revision 2; Office of Toxic Substances, U.S.Environmental Protection Agency: Washington, DC, 1985; EPA-560/5-85-012, NTIS PB86 109105. (9) Roth, Robert W.; Heys, J. Richard; Chien, David H. T.; Rotert, Gary A.; Saugier, Joseph H.; Erickson, Mitchell D. “Methods of Analysis for Incidentally Generated PCBsSynthesis of 13C-PCB Surrogates; Interim Report No. 3, Revision 1; Midwest Research Institute Kansas City, MO, 1982 (unpublished work). (10) Roth, Robert W.; Heys, J. Richard; Saugier, Joseph H.; Chien, David H. T.; Rotert, Gary A.; Erickson, Mitchell D. J. Labelled Compd. Radiopharm. (in press). (11) Erickson, Mitchell D. The Analytical Chemistry of PCBs; Butterworth Boston, MA, 1985. (12) Gebhart, Judith E.; Hayes, Timothy L.; Word-Stevens, Ann L.; Budde, William L. Anal. Chem. 1985,57, 2458-2463. (13) Alford-Stevens, Ann L.; Bellar, Thomas, A.; Eichelberger, James W.; Budde, William L. Method 680. Determination of Pesticides a n d PCBs in Water and SoillSediment by Gas Chromatography/Mass Spectrometry; Office of Research and Development, U.S. Environmental Protection Agency: Cincinnati, OH, 1985. (14) Erickson, Mitchell D.; Stanley, John S. Methods of Analysis for By-Product PCBs-Literature Review and Preliminary Recommendations; Office of Toxic Substances, U.S. Environmental Protection Agency: Washington, DC, 1982; EPA-560/5-82-005, NTIS PB83 126 573, 135 p. (15) Tindall, G. William; Wininger, Percy E. J . Chromatogr. 1980,196, 109-119.
76
Environ. Sci. Technol., Vol. 22, No. 1, 1988
(16) Collard, Randall S.; Irwin, Morris M., Jr. Talanta 1984,30, 811-818. (17) Westerberg, R. B.; Alibrando, S. L.; van Lenten, F. J. J . Chromatogr. 1984 284(2), 447-456. (18) Pittaway, Alan R.; Horner, Theodore W. Statistical Analysis of Data from a Round Robin Experiment on PCB Samples; Chemical Manufacturers Association: Washington, DC, 1982 (unpublished work). (19) Martelli, G. P.; Castelli, M. G.; Fanelli, R. Biomed. Mass Spectrom. 1981, 3(8), 347-350. (20) Cairns, Thomas; Siegmund, Emil G. Anal. Chem. 1981, 53(11), 1599-1603. (21) Pellizzari, Edo D.; Tomer, Kenneth B.; Moseley, M. Arthur In Advances in the Identification and Analysis of Organic Pollutants in Water; Keith, L. H., Ed.; Ann Arbor Science: Ann Arbor, MI, 1981; Chapter 12, pp 197-218. (22) Harless, R. L.; Oswald, E. 0.;Wilkinson, M. K.; Dupuy, A. E., Jr.; McDaniel, D. D.; Tai, H. Anal. Chem. 1980, 52, 1239-1245. (23) Stanley, John S. Methods of Analysis for Polychlorinated Dibenzo-p-dioxins (PCDDs) and Polychlorinated Dibenzofurans (PCDFs) in Biological Matrices-Literature Review and Preliminary Recommendations; Office of Toxic Substances, U.S.Environmental Protection Agency: Washington, DC, 1984; 560/5-84-001, 119 p. (24) Nero, Vincent, P.; Hudson, Robert D. Anal. Chem. 1984, 56, 1041-1043. (25) Erickson, Mitchell D.; Stanley, John S.; Turman, J. Kay; Going, John E.; Redford, David P. In Polynuclear Aromatic Hydrocarbons: Combustion Processes, Environmental Effects, and Biochemistry, Seventh International Symposium; Cooke, M., Dennis, A. J., Eds.; Battelle: Columbus, OH, 1983; pp 485-492. (26) Shore, F. L.; Martin, J. D.; Williams, L. R. Biomed. Environ. Mass Spectrum. 1986, 13, 15-19. (27) Bellar, Thomas, A.; Lichtenberg, James J. The Determination of Polychlorinated Biphenyls in Transformer Fluid and Waste Oils; Office of Research and Development, US. Environmental Protection Agency: Cincinnati, OH, 1981; EPA-600/4-81-045, 46 p. (28) U.S. Environmental Protection Agency Interim Guidelines and Specifications for Preparing Quality Assurance Project Plans; Office of Monitoring Systems and Quality Assurance, U.S.Environmental Protection Agency: Washington, DC, 1980; QAMS-005/80, 37 p. (29) Stalling, D. L.; Huckins, J. N.; Petty, J. D.; Johnson, J. L.; Sanders, H. 0. Ann. N.Y. Acad. Sci. 1979, 320, 48-59. (30) Parris, R. M.; Guenther, F. R.; May, W. E.; Cheder, S. N. NBS Spec. Publ. (U.S.) 1984, No. 674, 27-32. (31) Ballschmiter, K.; Zell, M. Fresenius’ 2. Anal. Chem. 1980, 302, 20-31. Received for review December 18, 1985. Revised manuscript received April 7,1987. Accepted August 21,1987. The work upon which portions of this publication are based was performed pursuant to Contracts 68-01-5915 and 68-02-3938 with the U S . Environmental Protection Agency.
