中药川芎超临界CO_2提取液的液相色谱-电喷雾多级质谱研究

Identification and Characterization of Supercritical Fluid Extracts of Rhizoma Chuanxiong by High Performance Liquid Chromatography-Ion Trap Mass Spectrometry

采用HPLC-MSn技术分析和鉴定了中药川芎超临界CO2提取液中的主要成分:洋川芎内酯A、Z-藁本内酯、新蛇床内酯、3-丁基苯酞和苯酞二聚体。液相色谱-离子阱质谱联用在正离子电喷雾电离、自动多级质谱模式下进行分析。样品在ECLIPSE XDB C18色谱柱上以含0.25%乙酸水溶液和含0.25%乙酸甲醇梯度洗脱分离。对藁本内酯等苯酞内酯电喷雾电离后的碰撞裂解机理进行了探讨。Z-藁本内酯的碰撞裂解的两个主要途径为:侧链断裂脱烯和开环脱水再脱羰。实验中没有观察到孤立的脱羰过程。而这些主要成分的加钠离子的碰撞裂解过程完全不同。

Main constituents, senkyunolide A, Z-ligustilide, neocnidilide, 3-butylphthalide, and ligustilide dimers, in supercritical CO2 fluid extracts of Rhizoma Chuanxiong, a popular Chinese traditional medicine, have been identified and characterized by high performance liquid chromatography -ion trap mass spectrometry. Separations were carried out on an ECLIPSE XDB C18 column by gradient elution with 0. 25% acetic acid and methanol（containing 0. 25% acetic acid）. An Agilent 1100 series LC/ MSD XCT system was operated under positive ESI and auto MS^n modes for mass spectrometric analysis. Collision-induced dissociation（CID） fragmentation of these phthalides was investigated and elucidated. Phthalides primarily underwent two ESI CID pathways： side-chain cleavage with losses of alkenes and ring-opening with elimination of H2O followed by losses of CO. Direct neutral loss of CO was not observed. Sodium adduct ions demonstrated completely different CID pathways.