Polystyrene-Based High Internal Phase Emulsion Polymer Monolithic Stationary Phase for Capillary Electrochromatography

A new macroporous poly(styrene-co-divinylbenzene)-based monolithic stationary phase for capillary electrochromatography (CEC) was prepared by using emulsion templating technique without using a charge bearing comonomer. In this preparation, styrene and divinylbenzene in the continuous phase of a high internal phase emulsion were copolymerized in the presence of 90 vol.% of internal aqueous phase. The resulting monolithic column had a well-defined interconnected open-cell structure with micro size spherical voids. It indicated an adequate electroosmotic flow (EOF) without any charge bearing monomer due to the presence of ionizable sulfate end groups formed by the initiator used in the polymerization. The effect of mobile phase composition (pH and acetonitrile content) and voltage on EOF mobility were examined. Furthermore, it was successfully used for the separation of alkylbenzenes with theoretical plate numbers up to 142 000 plates/m.