HIGH-SPEED SEPARATION OF CARBOXYLIC ACIDS BY CO-ELECTROOSMOTIC CAPILLARY ELECTROPHORESIS WITH DIRECT AND INDIRECT UV DETECTION

摘要

The separation of saturated and unsaturated mono- and dicarboxylic acids which are intermediates and reaction products in the conversion pathway of citric acid and itaconic acid in hot, compressed liquid water and supercritical water is performed with co-electroosmotic high-performance capillary electrophoresis. Both direct as well as indirect photometric detection can be carried out at a wavelength of 185 nm. Co-electroosmotic separation conditions are set up by adding 1,5-dimethyl-1,5-diazaundecamethylene polymethobromide (hexadimethrine bromide; HDB; polybrene) as an electroosmotic flow modifier to achieve fast separations in the range of minutes and below. The quantitative results achieved with direct and indirect UV detection are in good comparison with the values of published HPLC data. Using this method, process control is possible by fast component monitoring of the reaction solutions.