Abstract: A method for the determination of the residues of 38 pesticides in fruits was established. After being ground, the pesticide residues in samples were extracted with 1% acetic acid-acetonitril and dehydrated with anhydrous magnesium sulfate. Then, the pesticide residues in the supernatant were cleaned up with octadecylsilane (C18), primary secondary amine (PSA) and diatomite before being subjected to high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis. The separation was performed on an Accucore aQ column. The electrospray ionization mass spectrometry was operated in the positive mode using multiple reaction monitoring (MRM) and the analytes were quantified by the external standard method. The results indicated that the limits of detection (LODs) for all the pesticides were in the range of 0.3–26.2 μg/kg, and the limits of quantitation (LOQs) ranged from 0.6 to 52.4 μg/kg. The correlation coefficients (R) of the calibration curves were in the range of 0.999 5–0.999 9. The average recoveries at three spiked levels ranged from 70.1% to 119.3% (n = 6) with relative standard deviations (RSDs) of 2.7%–12.4%. The method was rapid, sensitive and precise, and could provide technical support for the determination of pesticide residues in fruits.

Key words: fruits, QuEChERS, high performance liquid chromatography-mass spectrometry, pesticide residues