目的建立测定血清中依那普利及其代谢物依那普利拉的液相色谱-串联质谱(LC-MS/MS)方法。方法血清样品中加入内标(酚妥拉明),甲醇直接沉淀。色谱柱为Varian Polaris C18-Ether(50mm×2.1mm,5μm),流动相为甲醇∶0.5%甲酸水溶液(40∶60,V/V)。流速为0.3mL·min-1。扫描方式为正离子多离子反应监测(MRM),依那普利、依那普利拉和内标的离子选择通道分别为m/z377.2→234.1、m/z349.3→206.1和m/z282.4→211.8。结果依那普利、依那普利拉的线性范围均为0.25～200μg·L-1,定量下限为0.25μg·L-1,提取回收率均大于90%,批内、批间RSD均小于10%。结论本方法操作简便,特异性强,灵敏度高,取血量少,符合生物样品的分析要求,可以用于依那普利及其代谢物依那普利拉的药动学研究。 Objective To establish a liquid chromatography-tandem mass spectrometry (LC-MS / MS) method for the determination of enalapril and its metabolite enalaprilat in serum. Methods Serum samples were added with internal standard (phentolamine), methanol precipitation. The column was a Varian Polaris C18-Ether (50 mm × 2.1 mm, 5 μm) with a mobile phase of methanol: 0.5% formic acid in water (40:60, V / V). The flow rate was 0.3 mL · min-1. Scanning mode was positive ions MRM, ion channel of enalapril, enalaprilat and internal standard were m / z377.2 → 234.1, m / z349.3 → 206.1 and m / z282 .4 → 211.8. Results The linear range of enalapril and enalaprilat was 0.25 ~ 200μg · L-1, the lower limit of quantification was 0.25μg · L-1, the recoveries were both higher than 90%. The intra-assay and inter-assay RSD were less than 10%. Conclusions This method is simple, specific, sensitive, and has low blood loss. It meets the requirements of biological samples and can be used for the pharmacokinetics study of enalapril and its metabolite enalaprilat.