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Label-Free Electrochemical Monitoring of Concentration Enrichment during Bipolar Electrode Focusing
Analytical Chemistry (2011)
  • Eoin Sheridan, University of Texas at Austin
  • Dzmitry Hlushkou
  • Robbyn K. Anand, University of Texas at Austin
  • Derek R. Laws, University of Texas at Austin
  • Ulrich Tallrek
  • Richard M. Crooks, University of Texas at Austin
Abstract

We show that a label-free electrochemical method can be used to monitor the position of an enriched analyte band during bipolar electrode focusing in a microfluidic device. The method relies on formation of a depleted buffer cation region, which is responsible for concentration enrichment of the charged analyte. However, this depletion region also leads to an increase in the local electric field in the solution near a bipolar electrode (BPE), and this in turn results in enhanced faradaic reactions (oxidation and reduction of water) at the BPE. Therefore, it is possible to detect the presence of the concentrated analyte band by measuring the current passing through the BPE used for concentration enrichment, or the concentrated band can be detected at a secondary BPE dedicated to that purpose. Both experiments and simulations are presented that fully elucidate the underlying phenomenon responsible for these observations.

Disciplines
Publication Date
August, 2011
Publisher Statement
Reprinted (adapted) with permission from Analytical Chemistry 83 (2011): 6746, doi:10.1021/ac201402n. Copyright 2011 American Chemical Society.
Citation Information
Eoin Sheridan, Dzmitry Hlushkou, Robbyn K. Anand, Derek R. Laws, et al.. "Label-Free Electrochemical Monitoring of Concentration Enrichment during Bipolar Electrode Focusing" Analytical Chemistry Vol. 83 Iss. 17 (2011)
Available at: http://works.bepress.com/robbyn_anand/4/