Ion intensity analysis of post-source decay fragmentation in curved-field reflectron matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of carbohydrates: for structural characterization of glycosylation in proteome analysis.

The various kinds of oligosaccharides were analyzed by using post-source decay (PSD) fragmentation method of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Since the curved field reflectron MALDI-MS can record all fragment ions in a single measurement, we can discuss the fragment ion intensity in PSD mass spectrum more accurately. The intensities of the PSD fragment ions indicate the fine structure of the saccharide chains. The type of glycosyl linkages could be determined by the ion intensity analysis, and the stereo isomers of monosaccharides were distinguished by the MALDI-PSD fragment ion analysis. The linkage isomers and structural isomers were also distinguished by this method. The ion intensity analysis of curved-field reflectron MALDI-MS could be a powerful tool for glycosylation analysis.