FIG. 4.

Effect of electric field magnitude on the electrokinetic separation of 5 μm and 15 μm particles in the bifurcating microchannel: the DC voltage applied to the inlet reservoir is 600 V (a), 800 V (b), and 1000 V (c), respectively, for the three columns from left to right. The correspnding electric fields in the main-branch are approximately 390 V/cm, 520 V/cm, and 650 V/cm. The four panels from top to bottom in each column show the supperimposed images at the bifurcation and at the exit of one side-branch, the experimentally determined PDF of the separated particles, and the predicted particle trajectories (blue and red lines are for 5 μm and 15 μm particles, respectively) at the exit of the side-branch. The scale bars represent 100 μm.