Counterflow in isotachophoresis: Computer simulation and experimental studies

Abstract

A computer model has been developed to predict the effects of co- and counter-current flows on electrophoretic transport. Model predictions are compared with experimental data obtained with the large-scale recycling isotachophoresis apparatus, recently developed in our laboratory. There were no significant changes in the steady state properties or the transient development of the Kohlrausch-adjusted profiles with and without flow. The application of counterflow in free flow isotachophoresis in early stages, before a steady state is achieved, can result in selective wash-out of slower sample components. Thus, the magnitude of counterflow can be used as a variable in optimizing separations. The characteristic features of the model render it also suitable for the simulation of electroosmotic flow in capillary electrophoresis in open tubes, where plug-type flow prevails.