液相色谱- 串联质谱法同时测定蜂蜜中4种四环素族抗生素及其3 种差向异构体

采用液相色谱-质谱联用技术，建立同时测定蜂蜜样品中4种四环素族抗生素及其3种差向异构体的方法。蜂蜜样品中残留的药物用EDTA-McIlvaine缓冲液提取，提取液依次经OASIS HLB及羧酸弱阳离子柱固相萃取柱富集、净化后，用流动相洗脱。洗脱液经微孔滤膜过滤，用流动相甲酸水-乙腈梯度分离，电喷雾-串联质谱进行测定。在多反应监测模式下，22min内7种药物基本实现分离以及定性定量。样品在10～500μg/kg添加范围内，回收率均在64.9%～91.0%之间，相对标准偏差(RSD)不大于10.5%。土霉素及差向土霉素、四环素及差向四环素的检测限为1μg/kg，金霉素及差向金霉素、强力霉素的检测限为2μg/kg。本方法灵敏、可靠，可用于蜂蜜中7种四环素类抗生素的同时检测(其中包括3种毒性代谢产物)。

Simultaneous Determination of 4 Tetracyclines and 3 Epimers in Honey by HPLC Coupled with Tandem MS

A method for simultaneous determination of 4 tetracyclines and 3 epimers in honey samples was developed by high performance liquid chromatography coupled with tandem mass spectrometry. The residues in honey samples were extracted by EDTA-Mcllvaine buffer, and cleaned up and condensed by OASIS hydrophilic-liphophilic balance (HLB) column and weak cation exchange (WCX and carboxylic acid) sequentially. Sample solution eluted from the WCX SPE column by mobile phase was filtered by micro-pours membrane, separated by LC-MS/MS with gradient elution using acetonitrile-formic acid solution as mobile phase and then qualitatively and quantitatively analyzed by ESI-MS/MS in a MRM mode. Baseline separation of 7 target drugs was achieved within 7 min, and qualitative and quantitative analysis was completed. The recovery rates of the spiked samples at trace levels were in the range of 64.9% to 91.0% with the relative standard deviation (RSD) less than 10.5% (n = 7). The detection limits were 1μg/kg for oxytetracycline, tetracyclines, 4-epitetracycline, 4-epioxytetracycline and 2μg/kg for chlortetracycline, doxycycline and epichlortetracycline. The developed method was sensitive and reliable, and can be successfully applied to the simultaneous detection of 7 target tetracyclines residues including toxic metabolites in honey.