[Determination of 239 pesticide residues in soil by ultra performance liquid chromatography-tandem mass spectrometry].

A method for the determination of 239 pesticides in soil samples by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) is presented. The sample was prepared with AOAC (Association of Official Analytical Chemists) QuEChERS method for the extraction (acetonitrile, anhydrous MgSO4, CH3 COONa). After filtered with a 0.2 microm membrane, the sample was separated and detected by UPLC-MS/MS performing on positive/ negative electrospray ionization (ESI +/-) and the multiple reaction monitoring (MRM) mode. In this study, 236 of the 239 pesticides' correlation coefficients were above 0.99, which counted 99% of all the analytes. The limits of detection (LODs) ranged in 0.69 - 29.04 microg/kg (S/N = 3). The recoveries of all the pesticides at 40 microg/kg spiked level were in the range of 50% - 150%, and the relative standard deviations (RSDs) were below 20%. In addition, the recoveries of 209 pesticides were in the range of 70% - 120%, and RSDs of 161 pesticides were less than 10%. The method is efficient, fast, simple, and accurate. The procedure is suitable for the determination of multi pesticide residues in soil.