Determination of tri- through heptachlorobiphenyls in water samples by SPME-GC-MS-MS: Comparison of PDMS and PDMS-DVB coatings

Solid-phase microextraction technique coupled to gas chromatography-mass sp ectrometry-mass spectrometry has been applied to the extraction of polychlo rinated biphenyls ranging from three to seven chlorine substituents. The be havior of two polymeric coatings, polydimethylsiloxane and polydimethylsilo xane-divinylbenzene was extensively studied. The influence of experimental parameters as extraction mode (direct and headspace approach), temperature, volume of sample, agitation, and sample time were evaluated. The two fiber s were adequate for polychlorobiphenyl (PCB) extraction and analytes could be quantified at the subpicogram per milliliter level with extraction times of 60 min. Nevertheless, comparison of extraction efficiencies showed the advantages of working with the mixed coating, specially for less chlorinate d PCBs. Linearity was evaluated for a 200-fold concentration range from fem togram per milliliter to picogram per milliliter level. The two coatings we re applied to the determination of the target analytes in two different mat rices. (C) 2001 John Wiley & Sons, Inc.