Cross-linked poly(vinyl alcohol) as permanent hydrophilic column coating for capillary electrophoresis

A fast method for the generation of permanent hydrophilic capillary coating s for capillary electrophoresis (CE) is presented. Such interior coating is effected by treating the surface to be coated with a solution of glutarald ehyde as cross-linking agent followed by a solution of poly(vinyl alcohol) (PVA), which results in an immobilization of the polymer on the capillary s urface. Applied for capillary zone electrophoresis (CZE) such capillaries c oated with cross-linked PVA exhibit excellent separation performance of ads orptive analytes like basic proteins due to the reduction of analyte-wall i nteractions. The long-term stability of cross-linked PVA coatings could be proved in very long series of CZE separations. More than 1000 repetitive CE separations of basic proteins were performed with stable absolute migratio n times relative standard deviation (RSD > 1.2%) and without loss of separa tion efficiency. Cross-linked PVA coatings exhibit a suppressed electroosmo tic flow and excellent stability over a wide pH range.