| A method was developed for the separation and determination of 7 chiral polychlorinated biphenyls(PCBs) congeners(PCB 45,PCB 91,PCB 95,PCB 132,PCB 136,PCB 149 and PCB 174) in fish samples.The target chemicals were extracted by accelerated solvent extraction，cleaned up by gel permeation chromatography,acidified with silica gel column and multi-layer silica gel column，and were further fractioned with alkaline alumina columns．The chiral PCBs were identified and quantified by gas chromatography-mass spectrometry with electron impact ion source(GC-EI/MS).Five commercially available chiral capillary gas chromatography columns(BateDex-325,CP-Chirasil,BGB-172SE,Chirasil-Dex and Cyclosil-B) were evaluated for their ability to separate enantiomers of 7 chiral PCBs.Among the columns studied,Cyclosil-B capillary column obtained the best results,providing the simultaneous separation of 7 chiral PCBs with the enantioselective resolution of 0.8-2.3.The calibration curves of these seven chiral PCBs showed good linearities in the range of 10-200 μg?L-1 with correlation coefficients 0.998-1.000.The limits of detection(LOD,S/N=3) were all below 5.0 ng?g-1.The method was applied in the determination of the analytes in spiked fish samples,with recoveries of of 89.2%-114% and relative standard deviations(RSDs,n=7) of 0.3%- 2.1%，suggesting the high degree of accuracy and efficiency of the established method．The developed method was applied in fish samples which collected from a reservoir surrounded by several e-waste recycling workshops in Guangdong.PCBs and enantiomer franctions(EFs) of chiral PCBs(PCB 45,PCB 91,PCB 95,PCB132,PCB 136,PCB 149 and PCB 174) were analyzed in three kinds of fish samples.The concentrations of chiral PCBs ranged from 386.7 ng?g-1 to 602.8 ng?g-1in fish smaples.The EF values of chiral PCBs(PCB 45,PCB 91,PCB 95,PCB 132,PCB 136 and PCB 174) were significantly different with those in standard solution,which meaned that these chiral PCBs had enantioselective enrichment and metabolism in fish tissue.In addition,the EF values of chiral PCBs of PCB 45,PCB 91,PCB 95,PCB 132 and PCB 136 in three kinds of fish tissue were similar,with an exception of PCB 174．The declined EFs of PCB 174 in Cirrhinus moliorella and Cirrhinus moliorella were rebounded in Ophicephalus argu.This result may suggest that the Ophicephalus argu and Cirrhinus moliorella or Carassius auratus preferred to biotransform different enantiomers of PCB congeners. |