Abstract:A simple pesticide analysis method was developed for the determination of carbendazim， imidaclo－ prid， acetochlor and metolachlor in corns based on dispersive solid phase extraction procedure combined with liquid chromatography-positive mode electrospray ionization-tandem mass spectrometric （LC-MS/MS）. The analytes were extracted with acid acetonitrile and cleaned up by primary secondary amine（PSA） and octadecyl silane （C18）. Qualitative and quantitative analyses were carried out for four analytes under the positive scanning models after the chromatographic separation on reversed phase C18 column with an gradient elution program of acetonitrile and 0.1 % formic acid aqueous solution. The coefficient of determination（R） was > 0.995 within the calibration linearity range of 0.5 μg/kg-100 μg/kg for the four peaticides. The average recoveries of carbendaz－ im， imidacloprid， acetochlor and metolachlor in corn samples were in the range 88.0 %-112.0 %with associat－ ed RSDs （n=5）≤ 9.5 % at the three spiked level. The limits of detection （LOD）of four analytes were 0.025，0.15， 0.15 μg/kg and 0.025 μg/kg， respectively. The method could meet the determination requirements of these four pesticides in corns.