Butyl acrylate porous polymer monoliths in fused-silica capillaries for use in capillary electrochromatography

Capillary electrochromatography incorporates features of both capillary electrophoresis and liquid chromatography. Butyl acrylate polymers, cast in-situ with heat initiated polymerization and no retaining frits have been made. Van Deemter plots of chrysene have been examined at a variety of operating temperatures to examine column behavior. Hmin moves to faster flow-rates and increases slightly in magnitude as temperature is increased. The longevity and reproducibility of the columns have been examined with a homologous series. Performance is very reproducible between two different columns of different diameters, operated on different systems and prepared from the same polymeriation batch. The relative standard deviation of retention factors is a maximum of 3.1% with most values calculated at less than 1%. The uniformity of the polymers as a function of length has also been studied with a series of polycyclic aromatic hydrocarbons, and the columns have proved to be very uniform across their length as measured by the consistency of retention factors with a maximum relative standard deviation of 3.4% and most values calculated between 1 and 2%. Plate numbers of between 65 000 and 80 000 plates/m have been attained for compounds with retention factors of 3 to 12. These columns have proved easy to make, are quite reproducible, and long lived.