液相色谱-串联质谱法快速测定猪肝脏中恩拉霉素残留量

建立了快速测定猪肝脏中恩拉霉素残留量的液相色谱-串联质谱(LC-MS/MS)分析方法。猪肝脏样品用0.1 mol/L盐酸-乙腈(3∶7,体积比)提取2次,离心收集上清液后,加入乙酸乙酯和正己烷液液萃取净化提取液,离心分层后吸取下层提取液经0.1%甲酸稀释定容后进行LC-MS/MS分析。采用Acquity BEH C18柱(100 mm×2.1 mm,1.7μm)进行色谱分离,以0.1%甲酸溶液-甲醇为流动相梯度洗脱;质谱采用电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式采集数据,基质校准外标法定量。恩拉霉素A和恩拉霉素B基质标准溶液在2.0~500μg/L质量浓度范围内与定量离子对峰面积呈良好的线性关系,方法检出限分别为3.0、4.0μg/kg,定量下限分别为10、12μg/kg,空白猪肝脏的加标回收率为80.8%~90.3%,批内相对标准偏差(RSD)为0.90%~4.5%,批间RSD为3.0%~4.3%。与已建立的方法比较,该方法简单快速,准确度和精密度均较好,能满足动物组织中恩拉霉素残留量分析的需要。

Rapid Determination of Enramycin Residues in Swine Liver by Liquid Chromatography-Tandem Mass Spectrometry

A rapid liquid chromatography-tandem mass spectrometric(LC-MS/MS)method was developed for the determination of enramycin in swine liver.The swine liver samples were extracted twice with 0.1 mol/L hydrochloric acid solution-acetonitrile(3∶7,by volume),then purified by liquid-liquid extraction with ethyl acetate and hexane after centrifugation,and finally analyzed by LC-MS/MS after dilution with 0.1%formic acid solution.The separation was performed on an Acquity BEH C18 column(100 mm×2.1 mm,1.7μm)with 0.1%formic acid solution-methanol as mobile phase by gradient elution.The LC-MS/MS analysis was in a positive electrospray ionization(ESI+)mode with multiple reaction monitoring(MRM)acquisition,and matrix-matched external standard method was used for quantitation.Results showed that there existed good linear relationships for enramycin A and enramycin B in the range of 2.0-500μg/L.The limits of detection for enramycin A and enramycin B were 3.0 and 4.0μg/kg,and the limits of quantitation for them were 10 and 12μg/kg,respectively.At the spiked levels of 15-60μg/kg,the recoveries ranged from 80.8%to 90.3%with intra-assay relative standard deviations of 0.90%-4.5%and inter-assay relative standard deviations of 3.0%-4.3%.Compared with the other LC-MS/MS methods,the method is more suitable for the determination of enramycin in animal liver tissues due to its simplicity and reliability.