建立了同时检测猪肉中18种苯二氮卓类药物残留的液相色谱-串联质谱(LC-MS/MS)分析方法。样品中的苯二氮卓类药物残留在pH 5.2的乙酸铵缓冲溶液中酶解后,用氨水调节pH值大于9.5,经乙酸乙酯-异丙醇(体积比5∶1)提取,正己烷去脂,MCX离子交换柱净化,采用电喷雾正电子模式电离,多反应监测模式检测,同位素内标法定量。结果表明:在0.5～50.0μg/L范围内18种苯二氮卓类药物的线性相关系数均大于0.999 0,检出限(S/N≥3)范围为0.01～0.13μg/kg,定量限(S/N≥10)范围为0.04～0.45μg/kg。添加浓度水平为1.0,2.0和5.0μg/kg时,平均回收率范围为76.0%～107.2%,相对标准偏差(RSD)范围为2.3%～9.1%。

A sensitive liquid chromatography-tandem mass spectrometric(LC-MS/MS) method has been developed for simultaneous determination of 18 benzodiazepines in pork sample.The sample was hydrolysised by enzyme in pH 5.2 ammonium acetate buffer followed by adjustment of pH value more than 9.5 with ammonium hydroxide.The benzodiazepines residues were extracted by aceticether-isopropol(5∶1,v/v),defatted by hexane and cleaned up by MCX solid phase extraction column.The analytes were detected by positive electrospray ionization tandem mass spectrometry in the multiple reaction monitoring(MRM) mode,and quantified by isotope internal standard method.Good linear correlations were found between the peak areas and concentration in 18 benzodiazepines in the range of 0.5-50.0 μg/L,the correlation coefficients were all above 0.9990.The limits of detection(LOD) of these 18 benzodiazepines were in the range of 0.01-0.13 μg/kg,limits of quantification(LOQ) were in the range of 0.04-0.45 μg/kg.The average recoveries of benzodiazepines were 76.0%-107.2%,at spiked levels of 1.0,2.0 and 5.0 μg/kg,the relative standard deviation(RSD) of the method was between 2.3% and 9.1%.