OBSERVATION OF INTERNAL MONOSACCHARIDE LOSSES IN THE COLLISIONALLY ACTIVATED DISSOCIATION MASS-SPECTRA OF ANTHRACYCLINE AMINODISACCHARIDES

The loss of internal monosaccharide residues from anthracycline aminod isaccharides has been studied using high and low energy collisionally activated dissociations (CAD). The mass spectra and low energy CAD spe ctra obtained using electrospray ionization on a quadrupole mass spect rometer 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 deuter ated 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. (C) 1998 American Society for M ass Spectrometry.