Fast separation of underivatized carbohydrates by coelectroosmotic capillary electrophoresis

A method for the rapid quantitative analysis of underivatized acidic sugars, monosaccharides and disaccharides using coelectroosmotic capillary electrophoresis was developed. Indirect UV detection at 254 nm using sorbate as background electrolyte was employed for monitoring the analytes. A highly alkaline pH value of the electrolyte system was chosen in order to achieve an electrophoretic mobility of the saccharides towards the anode. A dynamic reversal of the electroosmotic flow and, by this means, a codirectional movement of the negatively charged analytes and the electroosmotic flow is accomplished by employing a polycationic surfactant (hexadimethrine bromide), which is added to the background electrolyte. To further improve the resolution of specific carbohydrates, acetone is used as organic modifier. A practical application of the developed method for the fast determination of fructose, glucose, and sucrose in various soft drinks is provided.