液相色谱串联质谱法快速测定猪肉中克伦特罗残留量

摘要

A method was developed for determining residual clenbuterol in pork by liquid chromatography with tandem mass spectrometry. Five grams of pork samples were extracted with ethyl acetate under basic condition. Then, clenbuterol was extracted from the extract using formic acid solution. After defatting with hexane, the extract was directly used for determination of clenbuter by liquid chromatography with tandem mass spectrometry (LC-MS-MS) on an Acquity BEH C18 column with a mixture of 0.1% formic acid solution and methanol as the mobile phase under gradient elution conditions. The mass spectrometer was operated in multiple reaction monitoring (MRM) mode using positive electrospray ionization. The analyte was quantiifed with the isotope dilution and internal standard methods. Good linearity was obtained for clenbuterol in the concentration range of 0.05–10.0μg/L with correlation coefifcient more than 0.999. The recoveries of pork samples were 95.9%–101.5%at fortiifed levels of 0.25–0.75μg/kg. The proposed method exhibited a limit of detection of 0.10μg/kg and a limit of quantitation of 0.25μg/kg for clenbuterol. The relative standard deviations of intra-assay and inter-assay precision were between 3.3% and 4.6%, and between 4.1% and 5.1%, respectively. The method is demonstrated to be suitable for the fast determination of clenbuterol in pork.%建立快速测定猪肉中克伦特罗残留量的液相色谱串联质谱分析方法。猪肉样品在碱化的条件下用乙酸乙酯提取，提取后用甲酸溶液进行反萃取，萃取液经正已烷脱脂后直接进行液相色谱串联质谱（liquid chromatography with tandem mass spectrometry，LC-MS/MS）分析。采用Acquity BEH C18色谱柱分离，用0.1%甲酸溶液-甲醇作为流动相进行梯度洗脱，电喷雾正离子（ESI＋）模式电离，多反应监测（multiple reaction monitoring，MRM）模式检测，同位素稀释内标法定量。克伦特罗在0.05～10.0μg/L范围内建立的曲线相关系数大于0.999；方法检测限为0.10μg/kg，定量限为0.25μg/kg。克伦特罗在猪肉中的添加量为0.25、0.50、0.75μg/kg时，平均回收率在95.9%～101.5%之间，批内相对标准偏差（relative standard deviation，RSD）在3.3%～4.6%之间，批间RSD在4.1%～5.1%之间。该方法能满足猪肉中克伦特罗残留量快速分析的要求。