Abstract:This study aimed to research the use and residues of eight pesticides，such as imidacloprid in leek，and evaluate the dissipation difference of procymidone in open field and facility leeks.Samples were extracted using acetonitrile，cleaned up with carbon/amino solid phase extraction（GCB/NH2-SPE）cartridge，and evaluated with ultra-high-performance liquid chromatography-tandem mass spectrometry，using a matrix-matched external standard method.The results showed that at three spiked concentration levels between 0.01 mg/kg to 0.5 mg/kg，the average recovery values of all pesticides were approximately 81.8%-96.6%，with relative standard deviation of 0.3%-12.3%.As the maximum recommended dosage（450 g ai/ha）of the 50% procymidone wettability powder was sprayed once，the dissipation of procymidone in the open field and facility leeks fits first-order kinetics，with the corresponding procymidone half-life values being 5.3 d and 9.6 d，respectively.The dissipation of procymidone in the open field leek was significantly faster than that in the facility leek.Pesticide residues in the leeks from large-scale production bases were significantly lower than those in the leeks from retail planting.Thus，the reasonable application of pesticides can effectively improve the safety and quality of agricultural products.