title: Effect of alkali metal cationization and multiple alkali metal exchange on the collision-induced dissociation of loganic acid studied by electrospray ionization tandem mass spectrometry
abstract: Under electrospray ionization conditions loganic acid undergoes alkali metal (Li, Na and K) exchange and alkali metal cationization. Multiple exchanges of up to four alkali metal ions are observed. Different populations of metal exchanged species are produced during electrospray ionization. Collision-induced dissociation of ammonium cationized species is compared with that of metal cationized species to study the effect of metal cationization. Glycosidic cleavage and ring cleavages of aglycone and sugar moieties are the major fragmentation pathways observed during collision-induced dissociation. The fragmentations of the highly metal exchanged species indicate the opening of the pyran ring. Collision-induced dissociation of the various metal exchanged and metal cationized species also reveals the nature of the different populations. Copyright 2000 John Wiley & Sons, Ltd.
authors.affiliation: Central Drug Research Institute, Lucknow 226001, India.
authors.initials: KP
authors.lastname: Madhusudanan
authors.initials: K
authors.lastname: Raj
authors.initials: AP
authors.lastname: Bhaduri