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

The separation of saturated and unsaturated mono- and dicarboxylic aci ds which are intermediates and reaction products in the conversion pat hway of citric acid and itaconic acid in hot, compressed liquid water and supercritical water is performed with co-electroosmotic high-perfo rmance capillary electrophoresis. Both direct as well as indirect phot ometric detection can be carried out at a wavelength of 185 nm. Co-ele ctroosmotic 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 separati ons in the range of minutes and below. The quantitative results achiev ed with direct and indirect UV detection are in good comparison with t he values of published HPLC data. Using this method, process control i s possible by fast component monitoring of the reaction solutions.