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ANALYSIS OF 209 CHLORINATED BIPHENYL CONGENERS USING COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY-TIME-OF-FLIGHT MASS SPECTROMETRY IN THE 1-D MODE FOLLOWED BY THE 2-D MODE
Citation:
OSEMWENGIE, L. I., G. SOVOCOOL, AND M. Libardoni. ANALYSIS OF 209 CHLORINATED BIPHENYL CONGENERS USING COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY-TIME-OF-FLIGHT MASS SPECTROMETRY IN THE 1-D MODE FOLLOWED BY THE 2-D MODE. Presented at American Chemical Society Western Regional Meeting, Las Vegas, NV, September 24, 2008.
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Description:
Since the initial discovery of polychlorinated biphenyls (PCBs) in the environment, the detection and identification of certain PCB congeners using the traditional one dimensional (1-D) chromatographic technique has been very challenging, especially, separating the 46 isomeric pentachlorobiphenyls. Success in distinguishing certain isomeric PCBs from one another has been elusive due to the lack of instrumentation capable of true two-dimensional (2-D) or comprehensive gas chromatography (GC). To resolve most of the 209 PCB congeners, workers often resorted to the use of multiple gas chromatographic columns using two to five different GC phases. Until recently, instruments with comprehensive 2-D GC separation capability lacked both the necessary instrument data acquisition speed, and the required deconvolution software to resolve overlapping peaks. This research evaluated a recently developed comprehensive 2-D GC coupled with a time-of-flight (TOF) mass spectrometer (GC×GC-TOFMS) for the potential separation of 209 PCB congeners, using a sequence of 1-D and 2-D modes. A newly developed 30m, RTX-PCB column and a 1m DB-17 column were connected in tandem, separated by a modulator. In two chromatographic runs, 201 PCB congeners were distinguished, including 43 of the 46 pentachlorobiphenyl isomers. Many chlorinated biphenyls that could not be resolved chromatographically were resolved with the deconvolution power of the ChromaTOF® software. Advantage was also made of the “ortho effect,” which can distinguish PCBs having 2,2’-; 2,2’6-; and 2,2’,6,6’- chlorine substituted congeners from those important compounds without these substitutions. This work provided investigators with a new tool for a better front-end separation of PCB-specific congeners, and potentially, for more accurate human and environmental exposure data for risk assessments.