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 spectrometry-mass spectrometry has been applied to the extraction of polychlorinated biphenyls ranging from three to seven chlorine substituents. The behavior of two polymeric coatings, polydimethylsiloxane and polydimethylsiloxane-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 fibers 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 chlorinated PCBs. Linearity was evaluated for a 200-fold concentration range from femtogram per milliliter to picogram per milliliter level. The two coatings were applied to the determination of the target analytes in two different matrices. (C) 2001 John Wiley & Sons, Inc.