A new technique is described for the concentration and separation of ionic species in a microchannels. Concentration is achieved by balancing the electrophoretic velocity of an analyte against the bulk flow of solution in the presence of a temperature gradient. With an appropriate buffer, the temperature gradient can generate a corresponding gradient in the electrophoretic velocity, so that the electrophoretic and bulk velocities sum to zero at a unique point, resulting in analyte focusing. The technique for a variety of analytes including, amino acids, DNA, proteins, and particles, is shown to be capable of greater than 10000-fold concentration.
Citation: Analytical Chemistry
Issue: No. 11
Pub Type: Journals
focusing, microfluidics, preconcentration