HYDROPHILIC POLYMER-MODIFIED POLYPROPYLENE HOLLOW FIBERS WITH CONTROLLABLE ELECTROOSMOTIC FLOW FOR CAPILLARY ELECTROPHORESIS

Fused-silica capillaries often lack long-term stability and control of electroosmotic flow in capillary electrophoresis owing to the reactiv ity of the bulk silica structure in aqueous solutions of high or low p H. Polypropylene hollow fibers, an alternative to fused silica, have b een chemically modified to control the electroosmotic Bow. Ionic funct ional groups were used to vary or change the direction of electroosmot ic flow. Polymeric surface coatings containing sulfonic acid and quate rnary amine functionalities, and a novel polyphosphazene were bonded t o the polypropylene surface and evaluated for electrophoresis and elec troosmotic flow control. Varying magnitudes of electroosmotic flow wer e obtained with different concentrations or mixtures of these coatings . The resultant columns were successfully used for small-molecule sepa rations, such as substituted pyridines and DNA bases. (C) 1997 John Wi ley & Sons, Inc.