In-beam EI Mass Spectrometry of Monosaccharides-Appearance of Peaks above the Protonated Molecular Peak Originated from Fragmentation of the Protonated Dimer

Abstract

In-beam EI spectra of monosaccharides exhibited many peaks in the higher mass region than the protonated molecular peak. Those peaks are accounted for in terms of successive loss of water molecules from [2M+1]⁺, [2M+1-30]⁺ and [2M+1-60]⁺ ions. The intensities of those peaks increased with an increase in temperature of the sample heater. In-beam EI spectra of sucrose were also observed and turned out to be very similar to those of glucose.