Ion Mobility Study of Isomeric Carbohydrates as their Group I Metal Cation Adducts: Evidence for Isomer-Specific Conformations

摘要

Carbohydrates play numerous critical roles in biological systems. Characterization of oligosaccharide structures is essential to a complete understanding of their functions in biological processes; however, their structural determination remains challenging in part due to isomerism. Ion mobility spectrometry provides the means to resolve gas-phase ions based on their shape to charge ratios, thus providing significant opportunities for separation and differentiation of carbohydrate isomers. Here, we report the collisional cross sections for several groups of isomeric carbohydrates as their group I metal ion adducts. These data demonstrate that conformations assumed upon metal ion binding can in many cases be used to distinguish isomers. The influence of the carbohydrate structures and the ionic radii of the bound cations are both considered.