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Bipolar Electrode Focusing: The Effect of Current and Electric Field on Concentration Enrichment
Analytical Chemistry (2009)
  • Robbyn K Perdue, University of Texas at Austin
  • Derek R. Laws, University of Texas at Austin
  • Dzmitry Hlushkou
  • Ulrich Tallarek
  • Richard M. Crooks, University of Texas at Austin

Bipolar electrode focusing at discontinuous bipolar electrodes (BPEs) provides new insight into the faradaic current and electric field characteristics associated with the technique and allows for the controlled transport of a focused anionic tracer in a microfluidic channel. The findings corroborate our previously reported simulation results, which describe the formation of an extended electric field gradient leading to concentration enrichment. This gradient has been attributed to the passage of faradaic current through a BPE affixed to the floor of the microchannel. Our results demonstrate that the onset of faradaic current is coincident with the onset of concentration enrichment. Utilizing an array of microband electrodes, the tracer may be passed from one stationary position to another by rapidly relocating the BPE. However, the tracer movement is limited to one direction, confirming that the electrophoretic velocity of the analyte exceeds the electroosmosis-driven bulk fluid flow velocity at only the cathodic edge of the BPE.

Publication Date
November, 2009
Publisher Statement
Reprinted (adapted) with permission from Analytical Chemistry 81 (2009): 10149, doi:10.1021/ac901913r. Copyright 2009 American Chemical Society.
Citation Information
Robbyn K Perdue, Derek R. Laws, Dzmitry Hlushkou, Ulrich Tallarek, et al.. "Bipolar Electrode Focusing: The Effect of Current and Electric Field on Concentration Enrichment" Analytical Chemistry Vol. 81 Iss. 24 (2009)
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