Structural Analysis of Oligosaccharides by In-source Decay/Post-source Decay Experiments and Relative Ion Abundance Analysis of MALDI-MS

Abstract

Lewis-type trisaccharides were analyzed by MALDI-MS. The post-source decay spectra of Lewis^x(Le^x) and Lewis^a (Le^a) trisaccharides differed each other because of the β-elimination at C-3 in the N-acetyl glucosamine of the reducing-end of Le^x. The mechanism of the β-elimination in N-acetyl glucosamine of Le^x was analyzed by combined in-source decay/post-source decay (ISD/PSD) measurements. The combined ISD/PSD measurements were powerful tool for the fine analysis of the mechanism of the post-source decay of the oligosaccharides. ISD/PSD measurements were also useful for the assignments of the chemical species of PSD ions.