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

Independent control of electroosmosis is important for separation science t echniques such as capillary zone electrophoresis and for the movement of fl uids on microdevices. A capillary electrophoresis microdevice is demonstrat ed 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 co mpared to tens of kilovolts) still effectively altered electroosmosis. The efficiency for the control of electroosmosis by the applied external held i s improved by approximately 40 times over published values.