雷公藤二萜内酯的电喷雾及电子轰击质谱裂解规律研究

Study on the Diterpenoids of Tripterygium wilfordii by Electrospray Ionization Tandem and Electron Impact Mass Spectrometry

目的:研究雷公藤二萜内酯的质谱裂解规律。方法:采用电喷雾质谱(ESI-MS)和电子轰击质谱(EI)对雷公藤二萜内酯类化合物雷公藤甲素、雷公藤内酯酮以及雷酚内酯进行研究,对正离子扫描模式下雷公藤二萜内酯的主要特征碎片离子进行解析。结合文献报道的雷公藤二萜内酯质谱数据,总结归纳其ESI及EI质谱裂解规律。结果:电喷雾离子肼质谱[ESI-Trap-MS(+)]:[M+H]+准分子离子主要发生取代基断裂失去H2O、CH2CHCH3、CO以及CH2CO等中性分子,雷公藤甲素、雷公藤内酯酮和雷酚内酯形成m/z 197、183、169系列特征碎片离子。电喷雾飞行时间质谱[ESI-TOF-MS(+)]:[M+H]+准分子离子主要发生取代基断裂失去H2O、CO等中性分子以及发生环断裂失去中性碎片,形成m/z 277、185、93系列特征碎片离子。EI-MS:分子离子主要发生9(10)和5(6)位开环以及取代基断裂失去H2O、CO、CH4等中性分子和异丙基等自由基,形成m/z 149、105、91、71、55、43系列特征碎片离子。结论:首次报道了雷公藤二萜内酯的ESI及EI质谱裂解规律,根据质谱裂解特征碎片离子可对雷公藤二萜内酯进行快速、在线鉴别。

Objective： To study the diterpenoids of Tripterygium wilfordii by electrospray ionization tandem （ESI） and electron impact （El） mass spectrometry and establish the methods for quickly and on line identification of these diterpenoids. Methods： The diterpenoids were analyzed by ESI-MS and EI-MS under positive ion model. Results： In ESI-Trap-MS （ ＋ ） model, the quasi-molecu-lar ions [ M ＋ H]^＋ of the diterpenoids took place bond cleavage and generally lost neutral molecules such as H2O, CH2CHCH3 , CO and CH2CO, then generated characteristic fragment ion series （m/z 197, 183, 169）. In ESI-TOF-MS （ ＋ ） nlodel, the quasi-molec-ular ions [ M ＋ H ]^＋ of the diterpenoids took place bond cleavage and generally lost neutral molecules such as H2 O, CO, then genera- ted characteristic fragment ion series （m/z 277, 185, 93）. In EI-MS model, the molecular ions of the diterpenoids took place bond cleavage and generally lost neutral molecules such as H2 O, CO, CH4 , and isopropyl radical, then generated characteristie fragment ion series （m/z 149, 105,91,71, 55,43）. Conclusion： The ESI-MS and EI-MS characteristics of diterpenoids of Tripterygium wilfordii are reported for the first time. Based on these characteristics, the methods for quickly and on line identification of diterpenoids are es- tablished.