Simultaneous Determination of Six Acidic Herbicides and Metabolites in Plant Origin Matrices by QuEChERS-HPLC-MS/MS

This study presents a method for the simultaneous determination of six acidic herbicides and their metabolites in various matrices, including fruits, vegetables, grains and edible oils. The method employs acidified acetonitrile extraction combined with dispersive solid-phase extraction cleanup(dSPE) using magnesium sulfatem, Florisil, and graphitized carbon black (GCB). The analysis was performed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Acetonitrile and 2 mmol.L-1 ammonium formate aqueous solution with a volume ratio of 0.1%(v/v) formic acid were used as mobile phases, target pesticides were analyzed by HPLC-MS/MS in both positive and negative at an ESI ion source under multiple reaction monitoring(MRM). The mass concentrations of six herbicide pesticides and their metabolites showed good linearity with the corresponding peak area in the range of 0.5~50 μg/L, and the correlation coefficient was more than 0.993. The limits of method detection（LODs）ranged from 0.0001 to 0.008 mg/kg. The recovery rates of adding recovery experiments to cabbage, chives, pear, wheat flour and soybean oil were 69.8%~120%, and the relative standard deviation (RSD) was 0.6%~19.5%. The results indicate that this method is efficient and fast, and can be used for the detection of actual samples in various matrices.