POLY(ETHYLENE-PROPYLENE GLYCOL)-MODIFIED FUSED-SILICA COLUMNS FOR CAPILLARY ELECTROPHORESIS USING EPOXY-RESIN AS INTERMEDIATE COATING

An epoxy resin was used for fused-silica capillary column pretreatment before coating with a hydrophilic polymer for capillary electrophores is. The unique properties of the epoxy resins allow the deposition of a dense polymer layer on the column surface using the dynamic coating method. By using a free-radical cross-linking initiator, a hydrophilic polymer coating can be subsequently immobilized over the resin covere d surface. The coating is of sufficient thickness and hydrophilicity t o reduce protein adsorption and minimize electro-osmotic flow. Basic p rotein separations were achieved with high efficiency and reproducibil ity; one thousand consecutive runs on a single column gave an R.S.D. v alue of less than 2% in migration time. The coating was stable through out the pH range 4-11. The coating provides a simple, stable, and repr oducible means for deactivation of fused-silica columns for capillary electrophoresis.