Monosaccharides, separation from disaccharides

The separation of disaccharides and higher oligomers is not essentially different from the separation of monosaccharides, except that the volatility rapidly decreases with increasing molecular weight. Oligosaccharides may be transformed into volatile derivatives, commonly the trimethylsilyl ethers, either directly or after reduction. Other derivatives, such as trifluoroacetates, have been used, but the acetates have low volatility. Oligosaccharides are not usually converted into their methyl glycosides prior to trimethylsilylation. Detailed examples are listed in Table VII (see p. 130). 

D.P. 1-5) and peracetylated gluco- and xylo-oligosaccharides have been separated on Sephadex LH-20 eluted with DMF. Synthetic acetylated 3-()-linked disaccharides, obtained by Koenigs-Knorr procedures, were well separated from acetylated monosaccharide... 

Dipole moment (/i) (Section 1.9) The product of the amount of charge separation in a molecule times the distance of the charge separation. Disaccharide (Section 25.6) A carbohydrate formed from two monosaccharide units tliat are connected by a glycosidic bond. 

There are many publications and comprehensive handbooks on the thin-layer chromatography (TLC) of carbohydrates (e.g., Refs. 1 and 2). The reason is their great importance in life science and the great diversity of cases monosaccharide, disaccharide, trisaccharide, oligosaccharide, polysaccharide, aldose, ke-tose, triose, tetrose, pentose, hexose, as well as reducing and nonreducing sugars. In addition, when extracted from natural products or produced by fermentation, carbohydrates are accompanied by many impurities. That is why separation methods are used predominantly for their analysis. 

Starch is a macromolecule and would be excluded. It is followed by the oligosaccharides in decreasing degree of polymerization. Maltose is a disaccharide the other compounds are monosaccharides or small sugar alcohols. Fractions 8 and 9 are impossible to resolve because their masses are too similar. The elution order partly differs from the ion-exchange separation, and some compounds cannot be separated at all due to equal size. 

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