Study of the Fragmentation Patterns of Nine Fluoroquinolones by Tandem Mass Spectrometry

Fluoroquinolones (FQs) are a group of structurally related antibacterial agents, the fragmentation patterns of which are poorly investigated. This work reports a systematic study on the fragmentation pattern of a group of related FQs by electrospray ionization with multistage mass spectrometry (ESI-MSn) in positive mode. Potential dissociation pathways for the seven 7-piperazidine FQs and two 7-piperidine FQs are proposed and discussed. First, the loss of the peripheral groups was observed. Second, further steps involve the rearrangement of heterocyclic ring. In addition, the loss of CO2 or H2O in different pathways was observed. These fragmentation patterns provide important information for the determination of these compounds by liquid chromatography (LC)-MS.