液相色谱-电喷雾串联质谱法测定动物肌肉组织中的氯霉素残留

Determination of Chloramphenicol Residues in Animal Muscles by Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry

建立了动物肌肉组织中氯霉素残留检测的液相色谱-串联质谱确证方法.样本用乙腈-醋酸缓冲液(pH=5.0)(体积比80:20)匀质提取,乙酸乙酯液-液分配净化,以甲醇-水溶液(体积比40:60)作为流动相经反相色谱柱分离后进行质谱分析.采用负电喷雾电离源,在多反应监测模式下进行信号采集.定性诊断离子对为m/z 320.9/257.0,320.9/152.0和320.9/194.0;m/z 320.9/152.0用于外标法定量.空白样品及其添加实验表明,与标准CAP溶液相比,特征离子相对强度比值吻合、稳定,无基质成分的干扰,结合保留时间可实现准确定性.方法的检出限(S/N=3)和定量下限(S/N=10)分别为0.03和0.1μg/kg.不同肌肉基质样本添加水平在0.1～1.0μg/kg时,平均回收率为77%～90%,日内和日间相对标准偏差小于15%.该方法前处理简单、灵敏、回收率高、精密度好,符合残留的确证分析方法要求,已应用于日常工作中CAP残留的定性和定量分析.

A confirmatory method based on HPLC-MS-MS analysis was established for the determination of chloramphnicol(CAP)residues in animal muscles.The sample was homogenized in acetonitrile-0.1mol/L pH5.0acetate buffer(80∶20by volume)and was cleaned up byethyl acetate liquid-liquid extraction.Fol-lowing reverse-phase HPLC separation,the tandemmass spectral acquisition was done in the negative electro-spray ionization utilizing multiple reaction monitoring of three parent-daughter ion pairs:m/z320.9/257.0,320.9/152.0and320.9/194.0.The ion pair of m/z320.9/152.0was also used for quantitation.Analysis of blank and fortified samples showed that there was no matrix interference with these diagnostic ion pairs.The relative intensity of the CAP identification ion pairs in various matrices was stable and consistent withthe standard CAPsolution.Combiningwithretentiontimes,the method could be used for accurate qualita-tive analysis.The LOD(S/N=3)and LOQ(S/N=10)was0.03and0.1μg/kg,respectively.Atthe spik-ing levels of0.1-1.0μg/kg for various muscle matrices,the average recoveries were between77%-90%,and the intra-day and inter-day RSD were under15%.The method met the confirmatory analysis re-quirement for the forbidden drug residues,and has been used routinely for CAP qualification and quantifica-tion analysis.