CAPILLARY ELECTROPHORESIS AND ELECTROCHEMICAL DETECTION OF UNDERIVATIZED OLIGOSACCHARIDES AND POLYSACCHARIDES WITH SURFACTANT-CONTROLLED ELECTROOSMOTIC FLOW

Complex polysaccharide mixtures were analyzed directly without derivat ization by capillary zone electrophoresis in strongly alkaline solutio ns and electrochemical detection at a Cu electrode. The positively cha rged surfactant cetyltrimethylammonium bromide was included in the ele ctrophoresis medium in order to reverse the electroosmotic flow and pe rmit elution to be in order of increasing polysaccharide size. Carbohy drate samples analyzed by this approach included linear maltoses, enzy matically hydrolyzed starch, and commercially available dextrans of up to an average molecular weight of 18300. Detection by constant-potent ial oxidation at a Cu electrode was very sensitive, with detection lim its for individual carbohydrates generally below the femtomole level.