应用超高效液相色谱-四极杆飞行时间质谱建立了牛奶中28种兽药残留的快速筛查分析方法.牛奶样品经含体积分数0.2％甲酸的乙腈溶液提取,采用Oasis PRiME HLB固相萃取小柱净化.目标化合物经Agilent Eclipse Plus C18色谱柱(2.1 mm×l00 mm,3.5 μm)分离,以甲醇-甲酸水溶液为流动相进行梯度洗脱,使用电喷雾离子源,在正负离子模式下进行全扫描,可在20 rin内实现对28种兽药的良好分离.结果表明,牛奶中28种兽药的定量下限(LOQ,S/N=10)在1 ～10 μg/kg,平均回收率在68.9％～102.0％之间,相对标准偏差在4.30％～11.5％.%An analytical method was established for the simultaneous determination of 28 veterinary drugs in milk by ultra performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF-MS).The analytes in milk samples were extracted with aeetonitrile containing 0.2％ formic acid.The extract solution was purified by the solid phase extraction cartridge with Oasis PRiME HLB.The target compounds were separated on an Agilent ZORBAX Eclipse Plus C 18 column by gradient elution using methanol-0.1％ formic acid solution as mobile phase.And detected by MS in ESI and ESI-mode.The 28 compounds could be separated in 20 min.As a result,the limits of quantitation (LOQ,S/N=10) of 28 compounds were 1～10μg/kg in milk.The average recoveries of 28 compounds spiked at three concentration levels in the range of 68.9％ ～ 102.0％ with relative standard deviations of 4.30％-11.5％.The accurate mass databases of 28 compounds were established.
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