Determination Of12Kinds Of Dioxin-like Polychlorinated Biphenyls In Soil By Isotope Dilution Gas Chromatography Ion Trap Tandem Mass Spectrometry

Dioxin-like polychlorinated biphenyls (DL-PCBs), with the characteristics of high toxicity, persistence, long-distance transmission and bioaccumulation, are serious threat to human health. But due to low levels in environmental samples and vulnerable to interference from other homologues, determination of DL-PCBs is very difficult. Accurate determination of trace amounts of DL-PCBs in soil, as an critical intermediate medium of persistent organic pollutants, is very important.Soil samples are complex and have strong matrix effect. In this paper, combining the lower limit of detection of isotope dilution with the strong anti-interference ability of gas chromatography-ion trap tandem mass spectrometry, we developed a systemic method to determine12kinds of12kinds of DL-PCBs in soil samples. Pre-treatment and instrumental experiments were conducted. Some critical conditions, such as the choice of column, temperature program, collision-induced dissociation voltage, extraction solvent, and the method of purification were compared and optimized. We successfully simplified the experimental operation and saved time and solvent. Quality control experiment indicated that the average recovery rate of13C-labeled internal standard was58.47%-103.82%, method detection limit (MDL) of12kinds of DL-PCBs was0.006ng/g-0.029ng/g, RSD of the results was lower than20%. All the index can reach EPA1668requirements. Actual soil samples, collected from Beijing and Hangzhou were analyzed. The results showed that these areas were subject to different degrees DL-PCBs pollution.