Uronic acid and their oligomer microanalysis by normal-phase partition chromatography with fluorescence derivatization

Abstract

AbstractAlgal alginates, which consist of two uronic acids (i.e. D-mannuronate and L-guluronate), are important resources for a lot of industrial materials. The ratio of D-mannuronate to L-guluronate 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. To develop a fluorimetric high-performance liquid chromatography (HPLC) technique for microanalysis for uronic acid monomers and oligomers, a saline mobile phase and the postcolumn fluorimetric determination system of reducing saccharides with benzamidine were combined. 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 acid monomers and oligomers. The proposed method was successfully applied to uronic acid microanalysis and should prove useful for automated simultaneous microanalysis of uronic acid monomers and oligomers in alginate hydrolysates.