Analysis of chitin oligosaccharides by capillary electrophoresis with laser-induced fluorescence

A method, using capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection for analyzing chitin oligosaccharides is described. Chitin oligosaccharides were derivatized with 9-aminopyrene-1,4,6-trisulfonate (APTS) via reductive amination at 37 °C for 16 h (optimized conditions). The APTS–chitin oligosaccharides were analyzed using either an acidic citric acid–phosphate buffer or an alkaline borate buffer. The effects of buffer types, buffer pH values, and buffer concentrations on the separation were examined. The analytes were successfully separated by using a pH 4.6 citric acid–phosphate within 19 min. The APTS-derivatized chitin monosaccharide (d-glucosamine) migrated first. The analytes were also completely separated by using a pH 9.0 borate buffer within 24 min. Moreover, the specificity of enzyme digestion on chitin polysaccharides using the optimized APTS labeling procedure and the CE–LIF method was demonstrated.