Analyzing a mixture of disaccharides by IMS-VUVPD-MS

Comparative analyses utilizing collision-induced dissociation (CID) and vacuum ultraviolet photodissociation (VUVPD) for seven isobaric disaccharides have been performed in order to differentiate the linkage type and anomeric configuration of the isomers. Although an individual CID spectrum of a disaccharide ion provides information related to its structure, CID does not sufficiently differentiate mixture components due to the identical mass-to-charge values of most of the intense fragments. In contrast to the ambiguity of the CID analyses for the disaccharide mixture, VUVPD (157 nm) generates unique fragments for each disaccharide ion that are useful for distinguishing individual components from the mixture. When combined with a gas-phase ion mobility separation of the ions, the identification of each component from the mixture can be obtained.

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► Both CID and VUV photodissociation provide information of linkage type and anomeric configuration of isobaric disaccharides.
► Compared to CID, VUV photodissociation generates additional fragments that are helpful to distinguish each component from a mixture of disaccharide isomers.
► Extracted fragment ion mobility distributions reveal precursor ion mobilities from a mixture.