Determination of 34 Insecticide Residues in Vegetables by QuEChERS-High-Performance Liquid Chromatography Triple Quadrupole Linear Ion Trap Tandem Mass Spectrometry

This article established a rapid detection method for 34 pesticides in vegetables by combining QuEChERS purification method with high-performance liquid chromatography triple quadrupole linear ion trap tandem mass spectrometry. The samples were extracted with acetonitrile (containing 1% acetic acid), 1.5 g sodium acetate, 4 g anhydrous magnesium sulfate, and 1 g sodium chloride. The extract was further purified using 20 mg graphitized carbon black (GCB), 300 mg primary secondary amine (PSA), 200 mg octadecylsilane chemically bonded silica (C₁₈), and 1000 mg MgSO₄. Acetonitrile-water was chosen as mobile phase. The samples were analyzed using MRM-IDA-EPI mode, and an EPI database was established. Qualitative analysis was performed based on retention time, ion pair peak ratio, and EPI database, and quantification was carried out using matrix-matched external standard method. The study results indicated that using eggplant, garlic chives, cowpea, and spinach as representative matrices, the 34 pesticides showed good linear correlation with R²≥0.99011. The detection limits ranged from 0.16 to 1.81 μg/kg, and the quantification limits ranged from 0.52 to 6.02 μg/kg. The spiked recoveries of the samples were between 73.51% and 118.77%, and the precision was in the range of 0.01% to 14.27%. Vegetable samples were tested, with a detection rate of 58.23% for thiamethoxam. This method was characterized by its rapid and effective detection, simple operation, accurate data, and high sensitivity, making it suitable for the detection of 34 pesticides in vegetables.