Electron-Activated Dissociation for Glycan Identification with Ion Mobility-Tandem Mass Spectrometry

Abstract

The structural complexity and diversity of glycans has limited the understanding of the roles that these essential biomolecules play in homeostasis and disease. Methods that fully characterize glycan structure have been lacking. Tandem mass spectrometry dissociates glycans into fragments, the mass of which provides information about the intact structure. Electron-activated dissociation (ExD) provides more informative fragmentation than conventional collision induced dissociation, but access to this technique is restricted. We describe the development of ExD for glycan analysis using a linear, non-trapping cell mounted in an ion mobility-quadrupole-time of flight instrument. This configuration performs ExD on ion mobility-quadrupole selected glycans and was applied to discriminate between five isomeric human milk oligosaccharides using glycosidic cleavages, cross-ring cleavages, and secondary fragmentation patterns. This work shows that ExD can provide an additional level of characterization that is rapid enough to be compatible with liquid chromatography and ion mobility spectrometry.