Hirotaka Kakita1, Shouhei Seki2, Haruyoshi Ishijima2, Naoki Yanaoka1
1Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, 156-8550, Japan
2College of Humanities and Sciences, Nihon University, Tokyo, 156-8550, Japan
Algal alginates which consist of two uronic acids (i.e. D-mannuronate and L-guluronate) are important resources for a lot of industrial materials. The exact content of uronic acids and their oligomers is often an important feature in the study of their functional or biological properties. Uronic acid composition also influences the physical properties of polysaccharide preparations and gels in industry. Furthermore, the influences of the percentage and configuration of each uronic acid oligomer on biological and physiochemical properties of polysaccharides have also been reported. Therefore, a highly sensitive analytical technique for uronic acids and their oligomers would be useful for both biological studies and manufacturers’ quality control. The aim of this study was to develop a method for microanalysis of uronic acids and their oligomers in normal-phase partition chromatography (NPPC), with postcolumn fluorescence derivatization. NPPC columns were evaluated to determine a suitable column for the microanalysis. HPLC and fluorescence derivatization conditions were optimized for uronic acid microanalysis. Fluorescence measurement was performed at 288 nm for excitation and 470 nm for emission. A linear gradient elution system was found to be a suitable method for the simultaneous microanalysis of uronic acids and their oligomers. The proposed method was successfully applied to uronic acid composition microanalysis. The present method seems to be a useful for microanalysis of uronic acids and their oligomers.