Separation of simple saccharides

The term simple saccharide is used in the present context to refer to molecules consisting of between 1 and 6 saccharide units and thus 

Chemically modified alkylamine columns are the most widely used stationary phase for saccharide separations and are generally eluted with mobile phases consisting of acetonitrile-water mixtures. This mixture has been found to be far superior to others such as methanol-water (Rabel et al., 1976) and ethyl acetate-ethanol-water (Binder, 1980). It has been observed that as the water content of the mobile phase is increased the retention of saccharides is decreased. The columns are usually stable for periods of up to 3 months but 

An analysis of chicory root extract clearly demonstrates the usefulness of chemically modified alkylamine columns for the separation of saccharides according to their degree of polymerisation (Fig. 11.4.2). By changing the ratio of acetonitrile and water in the solvent from 60 40 to 75 25 these columns show considerable versatility in the separation of individual food saccharides (Fig. 11.4.3). Using a very similar column and eluent, monosaccharides from storage cell walls have been successfully separated and therefore this type of analysis can be used to monitor relative nutritional value it was also noted that the often problematical separation of galactose from glucose was achieved with this system (Barton et al., 1982). The combination of chemical modification (substituted oximes with UV detection) and a 

A dual column system has been described in which a complex mixture of saccharides from cell wall hydrolysates were separated on a chemically bonded amine colunm (Blaschek, 1983). The saccharides in the unresolved peaks were then further resolved by using cation-exchange chromatography which facilitated a baseline separation of all the carbohydrate components present in the extract. 

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Fig. 11.4.5. Separation of simple saccharides. Chromatographic conditions column, LiChrosorb Si 60 (5 jam) (250x4.0 mm) mobile phase, acetonitrile-water (75 25) containing 0.01% amine modifier flow rate, 3.0 ml/min detection, refractive index. Peaks Ri, ribose X, xylose F, fructose G, glucose S, sucrose Ma, maltose L, lactose Mb, melibiose Mt, maltotriose. Reproduced from Wight and Van Niekerk (1983b), with permission.

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