Simultaneous Determination of Thiamethoxamand Clothianidin in Leek by UPLC-MS/MS

[Aims] Ananalytical method for simultaneously detecting thiamethoxam and clothianidin residue in leek samples was established. [Methods] The sample was extracted by acetonitrile, cleaned by ENVI-Carb SPE column, separated by ultra performance liquid chromatography, detected by triple quadrupolemass spectrometry in multireaction monitoring model and quantitative with external standard method by matrix-match standard solution. [Results] Average recoveries of the method ranged from 72.4-98.6%, the relative standard deviation was 2.9-7.1%. The lowest detectable concentration of thiamethoxam and clothianidin in leek samples were 0.01 mg/kg, respectively. [Conclusions] The method was simple and reliable, met with the requirement of pesticide residues analysis, and could be applied for determining thiamethoxam and clothianidin residue in leek samples.