Abstract: An ultra performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantitative determination of four tetracycline residues in dairy products, including milk, yogurt and milk powder, has been established. In this method, the pretreatment and instrument operating conditions were optimized. Tetracycline residues were extracted into EDTA-Mcllvaine buffer and then cleaned up by an HLB solid-phase extraction cartridge. After the residues were eluted with a mixture of methanol and acetonitrile (1:9, V/V), the eluate was blown to dryness under nitrogen. The resulting residue was then redissolved. The analysis was carried out using positive ion electrospray ionization under the multiple reaction monitoring mode. The limits of quantification were 10 μg/kg for tetracycline, oxytetracycline, chlortetracycline and doxycycline in milk powder; the limits of quantification were 2 μg/kg in milk and yogurt. The recoveries of the tetracyclines fortified at levels from 2 to 100 μg/kg ranged from 63.1% to 100.6% with relative standard deviation of 1.8%–10.7%, and the matrix effects were 100.5%–122.1%. In conclusion, this method is accurate, rapid and highly sensitive and exhibits good repeatability and wide linearity. Thus it is suitable for the determination of tetracycline antibiotic residues in milk, yogurt and milk powder.

Key words: ultra performance liquid chromatography-tandem mass spectrometry; tetracyclines; veterinary residues; milk; milk powder

摘要： 建立超高效液相色谱-串联质谱法同时检测牛乳、发酵乳和乳粉3 种基质中4 种四环素类药物残留的检测方法。对前处理方法和仪器上机条件进行研究。以EDTA-Mcllvaine缓冲液进行提取，经HLB固相萃取柱净化，甲醇-乙酸乙酯（1∶9，V/V）洗脱，氮吹后复溶，采用电喷雾离子源正离子模式、多反应监测模式进行检测。结果表明：乳粉中四环素、土霉素、金霉素和强力霉素的定量限均为10 μg/kg；液态乳和发酵乳中4 种药物的定量限均为2 μg/kg；四环素类药物添加量为2～100 μg/kg时，回收率为63.1%～1

关键词: 超高效液相色谱-串联质谱；四环素类药物；兽药残留；牛乳；乳粉