连翘酯苷A和连翘苷LTQ Orbitrap MS裂解途径

LTQ Orbitrap MS on Fragmentation Pathways of Forsythoside A and Forsythin

目的:对连翘酯苷A和连翘苷的电喷雾质谱裂解途径进行研究。方法:使用LTQ-Orbitrap高分辨质谱仪,采用蠕动注射泵直接进样的方法,在正离子扫描模式下,分析连翘酯苷A和连翘苷的一级和多级质谱图。结果:连翘酯苷A的[M+Na]+准分子离子峰容易失去碎片C6H10O4(鼠李糖)或C9H8O4(咖啡酸),并在MS3谱中发现同时有两种不同来源的m/z321的离子,推断是由m/z 501与m/z 467离子分别丢失咖啡酸或鼠李糖的裂解而来。连翘苷的[M+Na]+准分子离子峰容易失去碎片C6H10O5(葡萄糖);同时在多级碎裂时,容易失去H2O,推断与分子结构中的酯键和糖苷键以及羟基有关。结论:本文首次使用LTQ-Orbitrap高分辨质谱仪报道连翘酯苷A和连翘苷的质谱裂解途径,根据高分辨特征碎片离子可对其进行快速在线鉴别,同时也为进一步研究连翘酯苷A和连翘苷的体内代谢过程与结构修饰提供数据支撑。

Objective： To study the fragmentation pathways of forsythoside A and forsythin by electrospray ionization mass spectrometry. Method： A syringe pump was used for the direct roop injections of reference compounds. Forsythoside A and forsythin were analyzed using LTQ orbitrap MS in positive ion mode. The first and multi-stage mass spectrum diagrams of forsythoside A and forsythin were obtained. Result： These were the fragmentation characteristics in the positive LTQ orbitrap MS. Forsythoside A was easy to lose C6H10O4 （rhamnose） or C9H804 （caffeicacid） , in the MS3 spectra there were two kinds of different sources of m/z 321 ion at the same time, We inferred that fragment ions were from m/z 501 or m/z 467 ion respectively losing caffeic acid or rat lee sugar cracking. Forsythin was easy to lose C6H1005 （glucose） , in multi-stage fracture it was easy to lose H2O. We inferred that ester and glycosidic bond and hydroxyl may contribute to it in the molecular structure. Conclusion： It first reported the fragmentation pathways of forsythoside A and forsythin by LTQ Orbitrap-high resolution mass spectrometer in positive ion mode. The characteristic fragment ions were can be recognized as a rapid identification features of these compounds. Meanwhile, the study can provide accurate data support for further research of metabolites and modifying structure of these compounds.