中成药样品用丙酮作为溶剂进行超声波萃取,所得提取液在不超过50 ℃的水浴中加热减压蒸发至干.加入水-乙酸-乙腈(49+1+50)混合溶液2.0 mL溶解残渣,所得溶液供液相色谱-串联质谱(LC-MS/MS)分析用,上述混合溶液在以后分析中用作流动相.Kromasil C18柱用作色谱柱固定相,在MS/MS分析中,选择大气压化学电离为离子源,以正离子扫描,选择离子检测模式和二级选择反应检测模式对马兜铃酸A进行定量和定性检测.以[M+NH4]+(m/z 359)为母离子,选择其二级离子中信号较强的碎片离子[M-NO2+H]+(m/z 298)作为定量及定性离子,并以碎片离子[M-CO2+H]+(m/z 296)为辅助定性离子.测定马兜铃酸A的线性范围在0.2~10.5 mg·L-1之间,方法的测定下限(10S/N)为0.07 mg·L-1.在3种不同浓度水平的标准加入量的条件下进行回收试验,测得回收率在89%~95%之间,测定值的相对标准偏差(n=6)均小于5.5%.

Sample of the medicine was extracted with acetone ultrasonically,and the extract was evaporated to dryness heated at below 50 ℃ in a water bath under reduced pressure.The residue was dissolved in 2.0 mL of the mixture of H2O+acetic acid+acetonitrile (mixed in the ratio of 49+1+50),which was used as mobile phase later,and used for LC-MS/MS determination.The Kromasil C18 was used as stationary phase in liquid chromatography.In the MS/MS analysis,APCI was used as ion source,and modes of SIM and SRM with positive ion scanning were taken for the quantitative and qualitative testing of aristolochic acid A.The [M+NH4]+ (m/z 359) was taken as the mother ion,and the fragment ion [M-NO2+H]+ (m/z 298) was taken as quantitative and qualitative ion.The fragment ion [M-CO2+H]+ (m/z 296) was taken as auxiliary qualitative ion.Linearity range for determination of aristolochic acid A was found between 0.2 and 10.5 mg·L-1.The lower limit of determination (10S/N) found for the method was 0.07 mg·L-1.Test for recovery was made at 3 different concentration levels,values of recovery were found in the range of 89%-95%,with RSD′s (n=6) less than 5.5%.