Characterization of glucosamine and N‐acetylglucosamine oligomers by fast atom bombardment mass spectrometry

The oligomers of N‐acetylglucosamine [degree of polymerization (d.p.) 2–6] and of glucosamine (d.p. 3–9) were systematically studied by the fast atom bombardment technique. Positive‐ and negative‐ion detection were used successively in each case. The latter provided more information in respect of the number of fragmentation pathways. In addition to the classical fragmentations usually obtained with other oligosaccharidic chains, new species specific to these two series were observed. They depend mainly on the nature of the substituents located on the C(2) positions of the glucosidic units constituting the chain.