Monosaccharide Analysis by Capillary Electrophoresis

In carbohydrate analysis efficient separation is indispensable, because a sample is usually accompanied by analogous compounds having very similar structures and properties. All carbohydrates contain hydroxyl group and most of them in addition have a characteristic functional group, such as the hemiacetal (aldoses), keto (ketoses), and carboxyl (aldonic and saccharic acids) groups. There are also compounds having two or more of such functional groups (e.g., uronic acids having the hemiacetal and carboxyl groups; sialic acids having the keto and carboxyl groups). Alditols are exceptional in having no such functional groups. In deoxy sugars a part of the hydroxyl group is eliminated, and in amino sugars, aminocyclitols, muramic acid, and sialic acids, it is substituted by the amino or acylamino group. Each of the aforementioned groups comprises homologues having different numbers of carbon atoms. The homologues composed of carbon atoms more than five have ring structures and have various epimers based on configurational differences. Thus, the number of possible monosaccharide species will reach almost an astronomical figure.