Abstract: [Objective] Develop a technology for the precise detection of nitroimidazole drug residues in goat milk using ultra-performance liquid chromatography-tandem mass spectrometry （UHPLC-MS/MS）,including metronidazole,dimetridazole,ronidazole and tinidazole,etc.[Method] The Goat milk samples were extracted with acetonitrile and citric acid buffer solution,and then purified by MCX cation exchange solid-phase extraction column and PEP-2 polymer solid-phase extraction column.After the nitrogen purge eluent was nearly dry,it was made up to 1 mL with a water-methanol containing 0.1% formic acid, and eluted gradually with 0.1% formic acid aqueous solution and acetonitrile in the flow phase. Chromatographic separation was accomplished on a BEH C18 column（2.1 mm×100 mm,1.7 μm chromatographic column） . The mass spectrometer conducted real-time detection through the positive ion multiple reaction monitoring（MRM）mode and completed quantitative analysis by external standard method combined with the matrix-matched standard curve.[Result] Within the concentration range of 1~80 ng/mL,the four nitroimidazole drugs had a good linearity,with correlation coefficients（r）were all greater than 0.998.The average recovery rate was 83.2%~106.8% at three spiked levels（1.0 μg/kg,2.0 μg/kg and 10.0 μg/kg）,the relative standard deviation（RSD）was 1.8%~20.1%.The detection limit of the method 1 μg/kg.[Conclusion] This method is simple to operate,sensitive and accurate,and is suitable for the detection of nitroimidazole drugs（metronidazole,tinidazole,dimedinidazole,ronidazole） residues in goat milk.

Key words: goat milk, nitroimidazole drug, ultra-performance liquid chromatography-tandem mass spectrometry