Theoretical evaluation of capillary electrophoresis performance

An analytical model (Datta and Kotamarthi, 1990) for the electrokinetic dispersion coefficient in capillary electrophoresis (CE), for the case of low zeta-potential, that accounts for the effects of pressure-driven and/or electroosmotic flow of the elutant, is utilized here to theoretically explore the performance of CE in terms of plate height, plate number, peak resolution, resolving power, and the time of analysis. Practical operating conditions for the voltage gradient and Poiseuille flow fraction, v, are explored that optimize CE column performance. The implications of the results in the rational design of CE columns are discussed. It is also shown that the superposition of Poiseuille flow on the natural electroosmotic flow, while allowing greater freedom in the choice of elutant velocity, does not always cause increased dispersion.