Studies of Post-source Decay of Carbohydrates and Their Structure Analyses

Abstract

When we analyze oligosaccharides by mass spectrometry, the fragment ions at glycosyl linkages show their sequences. However, it is difficult to distinguish between the linkage isomers or to analyze the types of glycosyl linkages. We have studied the post-source decay (PSD) of oligosaccharides in MALDI-MS, and we focused our attention on the abundance of the PSD ions to distinguish the linkage isomers. For example, the PSD ions produced by the cleavage of the α1→4 glycosyl linkage had higher abundance than those of α1→6 glycosyl linkage. The PSD ions produced by the cleavage of sialyl 2→3 linkages showed higher abundance than those of sialyl 2→6 linkages, and so on. These analyses of the linkage isomers of oligosaccharides have been performed systematically by MALDI-TOF mass spectrometry equipped with curved-field reflectron.