Electroosmotic flow control of fluids on a capillary electrophoresis microdevice using an applied external voltage

Independent control of electroosmosis is important for separation science techniques such as capillary zone electrophoresis and for the movement of fluids on microdevices. A capillary electrophoresis microdevice is demonstrated which provides more efficient control of electroosmosis with an applied external voltage field. The device is fabricated in a glass substrate where a 5.0 cm separation channel (30 mu m wide) is paralleled with two embedded electrodes positioned 50 mu m away in the substrate. With this structure, greatly reduced applied external potentials (less than or equal to 120 V compared to tens of kilovolts) still effectively altered electroosmosis. The efficiency for the control of electroosmosis by the applied external held is improved by approximately 40 times over published values.