ESI-Q-TOF-MS/MS用于碳青霉烯类抗生素及其中间体质谱裂解机理研究

Fragmentation pathways of carbapenems antibiotics and their intermediates using electrospray ionization quadrupole time-of-flight mass spectrometry

采用电喷雾-四极杆-飞行时间串联质谱(ESI-Q-TOF-MS/MS),在正离子模式下,对美罗培南等碳青霉烯类抗生素及其合成中间体共8种化合物的裂解规律进行了探讨.实验结果显示碳青霉烯类抗生素在该质谱条件下易形成[M+H]^+离子,其合成中间体则易观察到[M+Na]+离子.该8种化合物裂解途径相似,主要为分子内脱羧基反应、四元内酰胺环裂解反应及侧链结构中C—S键的裂解反应.

The fragmentation pathways of carbapenem antibiotics and their intermediates were investigated by electrospray ionization quadrupole time-of-flight tandem mass spectrometry（ESIQ-TOF-MS/MS）in positive mode.The experimental results showed that carbapenem antibiotics gave the prominent[M＋H]＋ions,while the intermediates yielded prominent[M＋Na]＋ions.All the eight compounds shared similar cleavage pathways,which involved the decarboxylation reaction,[2,2]-trans-Diels-Alder cleavage within the quaternary lactam ring,and the carbonsulphur bond cleavage reaction.