Derivatization of Carbohydrates

The monosaccharides comprise a number of isomers and homologues having very similar structures, basically composed of hydroxymethylor hydroxymethine groups linked to each other. In reducing monosaccharides the hemiacetal group is at the reducing ends inaddition to these polyhydroxylated basal structures. There are other series of monosaccharides with the ketal or carboxylgroup instead of or in addition to the hemiacetal group. Substitution of the hydroxyl group by the hydrogen atom or the aminogroup produces the deoxy sugar or the amino sugar, respectively. All these functional groups give monosaccharides hydrophilicproperties. With the exception of monosaccharide residues containing a carboxyl group, detection of these compounds followingchromatographic and electrophoretic separation is rendered difficult owing to their inherent lack of chromophores in the ultraviolet(UV) and visible spectrum regions. Obviously, oligosaccharides and polysaccharides composed of these monosaccharide unitshave a similar shortcoming with respect to their detection.