Pseudo-electrokinetic packing of high efficiency columns for capillary electrochromatography

An improved and easy electrokinetic packing procedure is presented for the production of stable capillary columns suitable for capillary electrochroma tography (CEC). In pseudo-electrokinetic packing a high electric field is u sed in conjunction with a hydrodynamic flow. The packing of silica-based re versed-phase columns can be achieved with basic, commercially available cap illary electrophoresis (CE) equipment in approximately 15 min. The procedur e is robust and a high success rate is achieved. No steps which might damag e the stationary phase are involved and only a minimum amount of packing ma terial is required. Columns packed according to the developed procedure are operated at high electric field strengths during the CEC separation, witho ut the application of a stabilising pressure. Columns are stable for at lea st hundred runs and were tested using mixtures of polycyclic aromatic hydro carbons and positively charged drugs. Separations were performed in a relat ively high conducting ammonium acetate buffer, with efficiencies of up to 2 83 000 plates/m. (C) 2000 Elsevier Science B.V. All rights reserved.