Minimizing Dispersion Introduced by Turns on Microchips

Abstract

For electrophoretic separations on microchip devices the introduction of turns into the separation channel often creates a geometrical contribution to analyte dispersion in addition to the dispersion generated from analyte diffusion and the injection plug length. We have developed a one-dimensional model which predicts the amount of geometrical dispersion introduced by turns. This model accounts for the migration length and field strength differences experienced by the individual molecules in the analyte band as they traverse the turn. It also accounts for the effects of transverse diffusion which occurs across the width of the channel as the analyte band migrates through the turn. The model describes the experimental data well.