Development of a conductivity-based photothermal absorbance detection microchip using polyelectrolytic gel electrodes

Honggu Chun, Patty J. Dennis, Erin R. Ferguson Welch, Jean Pierre Alarie, James W. Jorgenson, J. Michael Ramsey

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4 Citations (Scopus)


The development and application of polyelectrolytic gel electrodes (PGEs) for a microfluidic photothermal absorbance detection system is described. The PGEs are used to measure changes in conductivity based on heat generation by analytes absorbing light and changing the solution viscosity. The PGEs are suitable for direct contact conductivity measurements since they do not degrade with exposure to high electric fields. Both a 2-electrode system with DC voltages and a 3-electrode system with AC voltages were investigated. Experimental factors including excitation voltage, excitation frequency, laser modulation frequency, laser power, and path length were tested. The limits of detection for the 3-electrode and 2-electrode systems are 500. nM and 0.55. nM for DABSYL-tagged glucosamine, respectively. In addition, an electrokinetic separation of a potassium, DABSYL-tagged glucosamine, Rhodamine 6G, and Rhodamine B mixture was demonstrated.

Original languageEnglish
JournalJournal of Chromatography A
Publication statusAccepted/In press - 2017



  • Label-free detection
  • Microfluidics
  • Photothermal absorbance detection
  • Polyelectrolytic gel electrode

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

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