Capillary electrophoretic determination of the component monosaccharides in hemicelluloses

This study describes the precolumn derivatization of carbohydrates with p-aminobenzoic acid and their efficient separation as borate complexes by means of capillary zone electrophoresis, using a capillary tube of fused silica containing 150 mmol/L borate buffer, pH 10.0, as carrier. On-column UV-monitoring at 285 nm allowed the detection of aldoses and uronic acids in the lower femtomole range. Reproducible quantification of carbohydrates was achieved at least in the concentration range of 0.1–10 mmol/L by the relative peak area method, using cinnamic acid as internal standard. The method was successfully applied to the determination of the monosaccharide composition of both commercially obtained xylans as well as of hemicelluloses obtained by hydrothermal degradation of biomass.