Electrokinetic Particle Migration in Heterogeneous Electrolyte Systems

This paper presents a preliminary evaluation of an electrokinetic process for the buffer transfer and stacking of charged colloidal particles in solution. The mechanism exploits the effects of particle stacking across stacking across streamlines in a flow with electrical conductivity gradients transverse to the flow direction. Particle velocity fields and particle concentration measurements in a T-shaped microchannel system are presented. Upon application of an electric field, negatively charged particles are extracted from a low conductivity stream and stacked into a high conductivity stream. A simplified numerical model of the process with a commercial software code captures the generation of a transverse electric field.