CAPILLARY ZONE ELECTROPHORESIS OF NEUTRAL ORGANIC-MOLECULES IN ORGANIC - AQUEOUS-SOLUTION

Very good separations of non-ionic organic compounds have been achieve d by capillary zone electrophoresis (CZE) using a tetraheptylammonium salt as an additive in aqueous acetonitrile as solvent. A systematic s tudy was undertaken to determine the effect of experimental parameters on electroosmotic mobility and electrophoretic mobility. It was found that pH, acetonitrile concentration, and the type and concentration o f quaternary ammonium salt are important experimental variables. Under appropriate conditions, the separation window was enlarged and a broa d range of electrically neutral organics, including very hydrophobic c ompounds (e.g. polycyclic aromatic hydrocarbons) and fairly hydrophili c compounds were separated in a relatively short time. By adjusting th e separation conditions, high resolution CZE of a specific group of ne utral organic compounds could be achieved. A method for calculation of capacity factor was proposed and capacity factors for a variety of no n-ionic organic compounds were calculated.