Abstract: [Objective] To establish a rapid method for ultra-high performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） detection of amphenicol antibiotic residues in milk. The method should be capable of simultaneously detecting chloramphenicol,thiamphenicol,florfenicol and its main metabolite,florfenicolamine,and should have a relatively low limit of detection（LOD）. [Method] The milk was precipitated with trichloroacetic acid to remove proteins,extracted with ammoniated ethyl acetate,purified by MCX solid-phase extraction column,and re-solubilized in a methanol-water solution,separated on a Waters ACQUITY UPLC HSS T3 column（2.1 mm×100 mm,1.8 μm）,and eluted with a gradient of 25% methanol（channel A）and 75% water[containing 100 μL of ammoniated methanol（5%）in 200 mL water,channel B]. Mass spectrometry analysis was performed using multiple reaction monitoring（MRM）,and quantification was determined by external standard method. [Result] This method could complete the detection of 4 amphenicol compounds within 5 minutes. The recovery rates of the 4 amphenicol compounds at the added levels of 0.3,0.6,1.5 μg/kg was 77.3% to 106.4%,with the relative standard deviation ranging from 1.6% to 11.8%（n=6）. The LOD of the method was 0.1 μg/kg and the limit of quantification（LOQ）was 0.3 μg/kg. [Conclusion] This method was comprehensive,rapid,highly accurate,highly sensitive and stable,making it suitable for the detection of four amphenicol antibiotic residues in milk.

Key words: milk, chloramphenicol, thiamphenicol, florfenicol, florfenicol amine, ultra performance liquid chromatography-tandem mass spectrometry