Thin-layer electrophoretic separation of monosaccharides, oligosaccharides and related compounds on reverse phase silica gel

Study of the enzymatic transformation of fluorescently labeled oligosaccharides in human epidermoid cells using capillary electrophoresis with laser-induced fluorescence detection

Isomeric oligosaccharides of both beta Gal(1-->3)beta GlcNAc (type I) series and beta Gal(1-->4)beta GlcNAc (type II) series were studied by using capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection. A mixture of phenylboronic acid and sodium tetraborate was used in the CE running buffers to improve the electrophoretic separation of the oligosaccharides. Both series of the tetramethylrhodamine (TMR)-labeled substrates [beta Gal(1-->3)beta GlcNAc-O-TMR and beta Gal(1-->4)beta GlcNAc-O-TMR) and their potential enzymatic products were baseline resolved using CE. The high resolution provided by CE and the excellent detection limit (8.10(-23) mol, or 50 molecules) by LIF allowed for the determination of minor enzyme products in the presence of excess unreacted substrate. The action of competing enzymes acting on the common type I sequence was monitored after the incubation of human epidermoid carcinoma cells (A431) with a fluorescent substrate (beta Gal(1-->3)beta GlcNAc-O-TMR). The CE-LIF analyses showed the formation of both synthetic and hydrolytic products, suggesting the actions of glycosyltransferases and glycosidases in the cells.

Capillary zone electrophoresis of p-aminobenzoic acid derivatives of aldoses, ketoses and uronic acids

Aldoses, ketoses and uronic acids were derivatized with p-aminobenzoic acid and separated as their borate complexes by capillary zone electrophoresis, using a capillary tube of fused silica containing 150 mM borate buffer, pH 10.0, as carrier. The electrophoretic mobilities of 22 carbohydrates were determined and found to increase with increasing stability of the borate complexes formed. Besides the number of hydroxyl groups and the presence of substituents, complex stability depended most strongly on the configuration of the three vicinal hydroxyl groups at C2, C3 and C4. On-column UV monitoring at 285 nm allowed the detection of glucose with a lower mass detection limit of 15 fmol and a concentration sensitivity of 4 microM. Reproducible quantification of carbohydrates was achieved at least in the concentration range of 0.1-10 mM in reaction solutions by the relative peak area method, using cinnamic acid as internal standard. The method was applied successfully to the determination of the monosaccharide composition of polysaccharides extracted from Radix althaeae.

Thin-layer electrophoresis of hydroxyethyl starches on a modified silica gel support

The recent developed thin-layer electrophoresis on modified silanized silica gel was applied to the separation of hydroxyethyl starches (HES) and glycogen and of HES with different degrees of substitution. This method permits a rapid qualitative and semi-quantitative determination of HES in animal tissues such as liver, lung, heart and kidney after their disintegration with alkali and precipitation with ethanol.