A RESOLUTION EQUATION FOR ELECTROKINETIC CHROMATOGRAPHY BASED ON ELECTROPHORETIC MOBILITIES

A resolution equation for electrokinetic chromatography (EKC) was developed starting from the resolution equation for electrophoresis. The equation was used to predict the influences of the migration window and partitioning on resolution in EKC. It is theoretically shown that the migration window can have a dramatic effect-on resolution in EKC. Using a novel chiral surfactant, the influences of the migration window and partitioning on the separation of benzoin enantiomers were experimentally determined. The results obtained agreed with predictions based on the equation. The ability to obtain very high resolution values by migration window manipulation was demonstrated for the separation of N-methylpseudoephedrine enantiomers (alpha = 1.3). Specifically, the resolution was 2.4 under conditions of robust electroosmotic now (EOF) but increased to 11 when conditions of low EOF were employed.