连翘酯苷A和连翘苷LTQ Orbitrap MS裂解途径

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。

LTQ Orbitrap MS on Fragmentation Pathways of Forsythoside A and Forsythin

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 C₉H₈O₄ (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 C₆H₁₀O₅ (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.