Structural studies on the reducing-end sugar residues of polysaccharides by GLC and mass spectrometry

The reducing-end sugar residues of pachyman, amylose, dextran, and cold water-insoluble laminaran were isolated from the polymers as penta-O-methylhexitols or penta-O-ethylhexitols by treatment with a strongly basic anion-exchange resin (OH-form) after reductjion, alkylation, and acid hydrolysis. The penta-O-alkylhexitols obtained were analyzed by GLC and combined GLC-mass spectrometry as acetates and found to be in accord with expectations based on the known structures of the polysaccharides. 3- and 4-mono-O-acetyl-penta-O-alkylhexitols, which have the same substitution pattern, were easily distinguishable on the mass spectograms, using sodium borodeuteride for reduction.