USE OF PLATE NUMBERS ACHIEVED IN CAPILLARY ELECTROPHORETIC PROTEIN SEPARATIONS FOR CHARACTERIZATION OF CAPILLARY COATINGS

The number of theoretical plates achievable in capillary electrophoresis has been proposed for the characterization of the quality of capillary coatings. It is shown that, as predicted by theory, the efficiency is independent of capillary inner diameter and increases with increasing field strength as long as dispersive effects can be neglected. On the other hand, in contrast to chromatography, there is no linear range within which the plate numbers are independent of the amount or volume of sample injected (from aqueous solutions). By optimization of the injection technique (use of dilute aqueous protein solutions, electrokinetic injection techniques, short injection times), up to 3 . 10(6) theoretical plates can be achieved. The plates generated by injection of similar amounts of sample from buffer solutions are lower by a factor of 20.