[Determination of polychlorinated biphenyls in water by stable isotope dilution through automatic solid-phase extraction membrane coupled to gas chromatography-mass spectrometry].

OBJECTIVE: The method for analyzing of 20 polychlorinated biphenyls(PCBs) in water by stable isotope internal standard-automatic solid-phase extraction membrane(auto SPEM) coupled to gas chromatography-mass spectrometer(GC-MS) was established, and applied to the analysis of trace PCBs in water samples. METHODS: The sample backgrounds of bottled mineral water production in Fuzhou(groundwater), inland water in Fuzhou university city(surface water), tap water(pipe tip water) and stream water in Xiyuan Gong(water source of life) were analyzed by GC-MS. Surrogate solution(SS)internal standards including ~(13)C_(12 )PCBs stable isotope was used for quantification. The method was confirmed by calculating recovery rate(RR) and relative standard deviation(RSD) of spiked water samples(20, 40 and 80 ng/L, n=7). And recovery rates of SS were used to evaluate the effect of the pretreatment. And the method was used to determine PCBs of a total of 17 cross-sectiona river water in minjiang river tributaries upstream to the downstream estuary. RESULTS: The method detection limits(MDL) were 1. 9-6. 6 ng/L, and RRs were 70. 9%-127%, and RSDs were 0. 5%-13%. The RRs of SS were 40%-90%. Positive sample was not detected. CONCLUSION: The method of auto SPEM is less solvent, more automatic than traditional manual SPE. And the method is more accurate and reliable by stable isotope internal standard coupled to GC-MS. Therefore, it is useful for the trace PCBs determination of waters.