Use of Pressurized Liquid Extraction for the Simultaneous Analysis of 28 Polar and 94 Non-polar Pesticides in Agricultural Soils by GC/QqQ-MS/MS and UPLC/QqQ-MS/MS

Due to the wide range of pesticides that can be used in agriculture, the development of fast multiresidue methods that simultaneously determine polar and non-polar pesticides is greatly demanded. This study shows the development and validation of a multiresidue method for the analysis of 98 non-polar pesticides and 28 polar pesticides in soil. A simultaneous extraction step by pressurized liquid extraction was utilized. The optimum results were obtained using ethyl acetate-methanol (3:1, v/v) with 2 min of preheat time and 85 degrees C as the extraction temperature. The final determination of non-polar pesticides was performed by GC, whereas polar pesticides were determined by ultra-performance liquid chromatography (UPLC). Both GC and UPLC were coupled to triple-quadrupole analyzers operating in tandem MS. The optimized extraction procedure was validated. The average extraction recoveries were in the range 72-108% (10 mu g/kg) and 71-106% (50 mu g/kg), with RSD values <= 26%. The matrix effect was also evaluated, and matrix-matched standard calibration was finally applied for quantification. The suitability of the method was also checked by the analysis of a certified reference material. Furthermore, 26 real soil samples were analyzed by the proposed methods in order to assess their applicability. Several pesticides (e.g., bifenthrin, triadimefon, or endosulfan) were found in the samples.