[Journal of Chromatography A] Development of a conductivity-based photothermal absorbance detection
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.
Honggu Chuna, b, Patty J. Dennisa, Erin R. Ferguson Welcha, Jean Pierre Alariea, James W. Jorgensonc, J. Michael Ramseya, , a Department of Chemistry, University of North Carolina at Chapel Hill, Chapman Hall, CB#3216, Chapel Hill, NC 27599, United States b Department of Biomedical Engineering, Korea University, Hana Science Hall 466, Seoul, 02841, Republic of Korea c Department of Chemistry, University of North Carolina at Chapel Hill, Kenan Laboratories, CB#3290, Chapel Hill, NC 27599, United States Received 2 April 2017, Revised 15 June 2017, Accepted 16 June 2017, Available online 22 June 2017 Show less https://doi.org/10.1016/j.chroma.2017.06.053