Abstract: The author established a kind of method to check the residues of simetryn,chloroxuron,simazine,atrazine,acetochlor,butachlor in milk. The samples were extracted by acetonitrile,purified by solid phase extraction,and were determined by an ACQUITY UPLCTM BEH C₁₈ column with gradient elution using acetonitrile and water (containing 0.1% formic acid) as mobile phase. The mass spectrometric acquisitions were carried out by means of multiple reaction monitoring (MRM) in electrospray positive ionization mode. The detection limits of simetryn,chloroxuron,simazine,atrazine,acetochlor,butachlor were 0.1,1.0,0.2,0.1,4.0 and 4.0 μg/L. The calibration curves were liner from 1.0～50.0,10.0～500.0,1.0～50.0,1.0～50.0,20.0～1000.0 and 20.0～1000.0 μg/L.The results showed that this method had specific, sensitive,and suitable for determination on simetryn,chloroxuron,simazine,atrazine,acetochlor,butachlor in the milk.

Key words: ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS); pesticide; milk