Effects of Cationizing Agents on DIOS Mass Spectra of Poly(ethylene glycol)s

Abstract

Desorption/ionization on silicon (DIOS)-mass spectrometry of poly(ethylene glycol)s (PEG) were investigated using binary mixtures of NaI and other alkali metal iodides (LiI, KI, RbI, and CsI). A linear correlation was found between the relative ion intensities and the concentration ratios of the alkali metal ions. The smaller size metal ion adducts of PEG molecules were observed more intensively in the spectra. These results suggest that the interaction between PEG molecules and cationizing agents is important for the cationization of PEG molecules in DIOS.