Anomeric Memory of the Glycosidic Bond upon Fragmentation and its Consequences for Carbohydrate Sequencing

En route for de novo sequencing of underivatized oligosaccharides !
Carbohydrates and glycoconjugates are especially challenging to analyze due to their high stereochemical diversity which means it is difficult to distinguish between them and fully characterize using standard techniques and methods. Emerging technologies are beginning to address these issues such as Ion Mobility Mass Spectrometry (IM-MS) and the combination of 3 gas phase techniques : IR spectroscopy with IM-MS in-vitro enabling high-throughput with higher sensitivity, small samples, and analysis of mixtures to provide structural detail for each component. A hybrid analytical approach integrating molecular spectroscopy with mass spectrometry provides an adequate metric to resolve carbohydrate isomerisms, i.e the monosaccharide content, anomeric configuration, regiochemistry and stereochemistry of the glycosidic linkage. On the basis of the spectroscopic discrimination of MS fragments, the conservation of the anomeric memory of the glycosidic bond upon fragmentation is unambiguously demonstrated.