电喷雾离子阱质谱检测升麻素苷的正离子裂解途径

Fragmentation Pathways of Prim-O-glucosylcimifugin Revealed by Ion Trap Mass Spectrometry in Positive Mode

目的:采用电喷雾离子阱(ESI-MS)质谱技术对升麻素苷的结构和裂解途径进行研究。方法:采用蠕动注射泵直接进样,ESI-MS正离子模式检查,流速0.3 mL/h,毛细管电压为4 500 V,雾化器压力,干燥器流速和干燥器温度分别为10 psi,5 L/min和350℃,质量扫描范围m/z 100～800。结果:采用ESI-MS获得了m/z 469[M+H]+,采用ESI-MS2获得了m/z 397和307碎片离子,而采用ESI-MS3主要获得了m/z 365,289,259,235,211,219,205和177等碎片离子。ESI-MS产生分子离子峰稳定,主要碎片离子m/z 307为二氢呋喃色原酮碎片离子,归属了其主要特征碎片离子,分析和讨论了该化合物的结构和质谱特征。结论:ESI-MS正离子模式下适用于检测升麻素苷各级碎片裂解,归属了主要的碎片裂解途径,其方法快速,简便,可为进一步研究升麻素苷的体内代谢过程与结构修饰提供实验依据。

Objective The structure and fragmentation pathway of prim-O-glucosylcimifugin were elucidated by electron spray ionization-ion trap mass spectrometry(ESI-MS).Methods A syringe pump was used for the direct loop injections of reference compound.The ESI source was used and operated in negative ion mode,and the flow rate was set at 0.3 mL/h.Typical operating conditions were described as follows: drying gas(N2) temperature of 350 ℃,10 L/min drying gas flow,40 psi nebulizer gas(N2) pressure,and 4,500 V of capillary voltage.The full-scan MS spectra were obtained by scanning from m/z 100-800.Results Quasi-molecular ion peak m/z 469 + and the fragment ion of m/z 397 and 307 were detected by ESI-MS and ESI-MS2,respectively,and the main fragment ions of m/z 365,289,259,235,211,219,205 and 177 were found by ESI-MS3.The molecular ion fragment m/z 469 was stable and the major product ion at m/z 307 belongs to dihydrofurochromone.The characteristics of the fragment routes were discussed on the basis of ESI mass spectra.Conclusion It is suitable for determination the fragmentation and investigation of the fragmentation pathways of prim-O-glucosylcimifugin by ESI-MS in positive mode.The method is rapid and simple;it can provide the experimental data for studying pharmacokinetics in vivo and modifying structure for prim-O-glucosylcimifugin.