Mathematical Modeling of Capillary Electrophoresis in Rectangular Channels

Electroosmotic flow in rectangular channels with nonequal zeta potentials of the walls was studied. It was shown that in such channels the electroosmotic flow velocity profile may deviate substantially from the usual plug flow profile. This nonuniformity of electroosmotic flow leads to the Taylor dispersion and decreases in the efficiency and resolution of capillary electrophoresis in rectangular channels. Even the 10% difference in the values of the zeta potentials of the opposite walls of the channel leads to the loss of resolution. Thus these effects must be carefully taken into consideration when capillary zone electrophoresis (CZE) is realized in the rectangular channels, especially in the case of micro-CZE.