We explore the capability of SLIM-based IMS for isomer selectivity in combination with cryogenic, messenger-tagging IR spectroscopy.

Despite the essential role that glycans play in many biological processes, their isomeric complexity makes their structural determination particularly challenging. Tandem mass spectrometry has played a central role in glycan analysis, and recent work has shown that fragments generated by collision-induced dissociation (CID) of disaccharides can retain the anomeric configuration of the glycosidic bond. If this result proves to be general, it would provide a powerful new tool for glycan sequencing. In this work, we use messenger-tagging infrared (IR) spectroscopy to investigate the generality of anomer retention in CID by exploring different fragmentation channels in glycans of increasing complexity. Our results demonstrate that anomericity seems to be retained irrespective of fragment size and branching.