Mass spectrometry of partially methylated alditol acetates derived from hydroxyethyl starch

The degradation and derivatization of hydroxyethyl starch to partially meth ylated alditol acetates (PMAAs) allows its detection by gas chromatography/ mass spectrometry, The derivatization was performed by permethylation of th e carbohydrate, hydrolysis of the permethylated polysaccharide, reduction o f the resulting monosaccharides to alditoles and finally acetylation. A clo se similarity in the fragmentation of the PMAAs obtained mas observed in bo th electron ionization (EI) and chemical ionization (CI) mass spectra owing to the comparable structures of the derivatives. CI measurements permitted the recognition of introduced hydroxyethyl groups in the glucose residues by detection of [M+ + 1] - 60 signals. Investigations concerning the EI fra gmentation schemes allowed secure determinations of monohydroxyethyl monosa ccharides and differentiations between the possible positions (C-2, C-3 and C-6) of the substituted hydroxyethyl groups. Proposed generations of the m ain fragment ions are presented. Copyright (C) 2000 John Wiley & Sons, Ltd.