Observation of Internal Monosaccharide Losses in the Collisionally Activated Dissociation Mass Spectra of Anthracycline Aminodisaccharides

Abstract

The loss of internal monosaccharide residues from anthracycline aminodisaccharides has been studied using high and low energy collisionally activated dissociations (CAD). The mass spectra and low energy CAD spectra obtained using electrospray ionization on a quadrupole mass spectrometer were consistent with a structure in which positions of the two monosaccharide residues were reversed. Key fragment ions observed in the product ion spectra of the peracetylated derivative and the deuterated analog were used to provide evidence that a rearrangement process had occurred. Mass-analyzed ion kinetic energy spectrometry data were also consistent with a rearrangement.