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.