Determination of 4 Insecticides Residues in Leek by Ultr Performance Liquid Chromatography-Mass Spectrometry

[Aims] A method was developed for the simultaneous determination of imidacloprid, phoxim, chlorpyrifos and cypermethrin residues in leek. [Methods] The samples were extracted with acetonitrile, clean up by GCB-SPE column, detected by ultra liquid chromatography-mass spectrometry under multiple reaction monitoring mode, and quantitated with external standard method by matrix-match standard solution. [Results] With the addition concentration of 0.01-0.1 mg/kg, the average recoveries of the insecticides ranged from 73.8-106.7% with the relative standard deviation was 2.7-15.9%. The limit of detection for these four pesticides was 0.003 ng, and the limit of quantification was 0.01 mg/kg. [Conclusions] The method is simple and reliable, which met the requirement of pesticide residues analysis, and could be applied for determination of imidacloprid, phoxim, chlorpyrifos and cypermethrin in leek samples.