Simultaneous Determination of 46 Pesticide Residues in Tomatoes by QuEChERS Method Combined with Gas Chromatography-Mass Spectrometry

An analysis method for simultaneous determination of 46 kinds of fungicides and insecticides residues in tomatoes by QuEChERS method combined with gas chromatography-mass spectrometry was established. The samples were extracted with acetonitrile, then purified up with PSA, C₁₈ and anhydrous MgSO₄, separated by a HP-5MS chromatographic column, analyzed using multiple reflection monitoring (MRM) mode, and quantified by matrix-matched external standard method. The result showed that, the 46 kinds of pesticides showed good linearity when they were in 0.005～0.500 μg/mL (R²>0.999). The limits of detection of the 46 kinds of pesticides were in 0.07～2.63 μg/kg, and the limits of quantitation were in 0.21～8.39 μg/kg. The average recoveries were 70.40%～115.08% with the relative standard deviations of 0.22%～4.89% at the spiked levels of 0.0025, 0.025 and 0.25 mg/kg. Residues of chlorpyrifos and azoxystrobin were detected in 9 of the 50 batches of tomato samples, with the content ranging from 0.0043～0.0365 mg/kg, which did not exceed the limit value specified in GB 2763-2021. The method was rapid, simple, sensitive and accurate, which could meet the detection of multiple pesticide residues in tomato.