Abstract: A method for rapid and accurate determination of 10 pesticide residues in garlic by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry was developed. Samples were extracted by acidified acetonitrile, dehydrated with anhydrous magnesium sulfate (500 mg) and cleaned up by primary secondary amine (PSA, 500 mg) and octadecyl bonded silica gel (C₁₈, 500 mg). The target samples were separated by Waters C₁₈ column with gradient elution using acetonitrile and 0.1% formic acid aqueous solution as mobile phases. The positive ion mode and multiple reaction monitoring (MRM) mode were used in the analysis, and the analytes were quantified by external standard method using matrix-matched calibration curves. The limits of detection of the 10 pesticides were in the range of 0.020 to 0.800 μg·kg^-1 and the limits of quantitation were in the range of 0.067 to 2.670 μg·kg^-1. The correlation coefficients in the linear range were more than 0.99. Average recoveries were from 73.4% to 109.0% and the relative standard deviations (RSD) were from 1.2% to 9.8%. The method is simple, easy, sensitive, reproducible and applicable to the simultaneous determination of 10 pesticide residues in garlic.

Key words: garlic, pesticide, QuEChERS, ultra performance liquid chromatography-tandem mass spectrometry