A study on the condition for differential electrophoretic transport at a channel entrance

J. Rafael Pacheco, Kangping Chen, Mark Hayes

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Electrophoretic differential transport of ionic species in a solution moving from a large reservoir into a small channel is investigated numerically. The system setup is similar to the experiments of Polson, Savin, and Hayes (J. Microcol. Sep. 2000, 12, 98), where the bulk flow into a fused-silica capillary was driven by a pressure differential. A critical condition for achieving the defined differential transport near the channel entrance is found and this condition is solely determined by a dimensionless parameter when the geometry of the system is prescribed. This dimensionless parameter is the ratio between the electrophoretic migration velocity of the species based on the apparent electric intensity and the centerline fluid velocity of the fully developed channel flow. Species concentration distributions are also computed for various conditions. A separation technique can be derived from the experimental condition where a targeted division of species can be created at the channel entrance.

Original languageEnglish (US)
Pages (from-to)1027-1035
Number of pages9
Issue number7
StatePublished - Apr 2007


  • Electrokinetics effects
  • Electrophoretic focusing
  • Low reynolds number flow

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Clinical Biochemistry


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