Equation for the description of the resolution of charged solutes in micellar electrokinetic capillary chromatography

The migration behaviour of charged solutes in micellar electrokinetic capillary chromatography is affected by both the electrophoretic properties of the solute and its interaction with the micelles. Both must therefore be considered to obtain an adequate description of the migration behaviour and thus resolution. A novel equation is presented, in which the resolution is expressed as a function of the micellar interaction (capacity factor for charged solutes) and the electrophoretic mobility (free zone migration time) of the charged solute. Simulations reveal the dependence of the resolution of two closely migrating solutes on both distinct interactions, which is clearly different as compared to the separation of neutral solutes and general guidelines with respect to better separation are deduced. Experimental data illustrate that this equation can be used to gain more insight in the corresponding migration mechanisms. Furthermore, using this knowledge, it is possible to adjust the experimental parameters to achieve better resolution.