Abstract: Although toxaphene is now banned in use, the analysis of toxaphene has attracted increasing interest due to its persistence and widespread atmospheric transport in the environment. A new method based on isotope dilution-gas chromatography-tandem mass spectrometry (ID-GC-MS/MS) has been developed for the determination of three toxaphene specific congeners comprised of Parlar No. 26 (P26), Parlar No. 50 (P50) and Parlar No. 62 (P62) in soil. 13C10-labeled indicator toxaphene solution was added to the sample prior to pretreatment. Then the sample was extracted using pressurized liquid extraction (PLE) followed by purification on multilayer acidic silica column and neutral silica column. The eluent was concentrated under gentle nitrogen gas flow and spiked with the injection of internal standard of 13C10-chlordane. Identification and quantification of the analytes were carried out in the multiple reaction monitoring (MRM) mode after the GC separation. The linear range was 20~800 μg/L for three congeners, limits of detection (LOD) ranged from 3.0 to 6.0 pg. The five point calibration curves showed a good linearity for all the congeners (R2 ＞ 0.99). The relative standard deviations (RSDs) were below 11% for and the spiked recoveries were in the range of 55%~110%. The developed analytical method is suitable for the determination of toxaphene specific congeners in soil.

Key words: gas chromatography (GC), indicator toxaphene, soil , tandem mass spectrometry (MS/MS), isotope dilution