取粒径在0.18~0.25 mm的药材粉末于提取罐中,用水作提取剂,在110 ℃、压力为15 MPa、功率为780 W的条件下进行微波提取(PMAE) 5 min,经离心后取上清液为提取液。提取液经无水乙醇处理提纯后得到待测物的甲醇溶液,从中分取部分溶液按选定条件用液相色谱-质谱(LC-MS)联用做定性分析,用高效液相色谱(HPLC)做定量分析。LC-MS结果表明:提取液中含有氧化苦参碱、氧化槐果碱、槐定碱、苦参碱和槐果碱,与其它3种提取方法比较,PMAE的提取率高且提取时间短。HPLC定量时,采用C18色谱柱,以不同比例的甲醇、乙腈和0.1%氨水溶液(pH 10.3)的混合溶液作流动相进行梯度淋洗,可分离上述5种生物碱,以峰面积和浓度间的线性关系进行定量。5种生物碱的回收率在93.9%~101.0%之间,测定值的相对标准偏差(n=5)在0.53%~2.6%之间。

Sample of the crushed drug with sizes between 0.18-0.25 mm was placed in a closed extraction vessel and treated by microwave assisted extraction for 5 min with H2O at 110 ℃ under a pressure of 15 MPa, with microwave power of 780 W (PMAE). After centrifugation, the supernatant was collected as the extract. After purification by treatment with absolute alcohol, the analyte in methyl alcohol was used for analysis. Aliquots were taken for qualitative analysis by LC-MS, and for quantitative analysis by HPLC separately. Five alkaloids (i.e., oxymatrine, N-oxysophocarpine, sophoridine, matrine and sophocarpine) were identified by LC-MS. The method of PMAE, as compared with 3 other extraction methods, was proved to be more efficient by having high rate of extraction and requiring less time for extraction. In HPLC analysis, the 5 alkaloids were effectively separated by gradient elution with mobile phase of mixtures of methanol, acetonitrile and 0.1% ammonia solution (pH 10.3) of different ratios on C18 column. Linear relationships between peak area and concentration of the 5 alkaloids were used as basis for quantification. Results of recovery found were in the range of 93.9%-101.0% with RSD′s (n=5) in the range of 0.53%-2.6%.