MicroScale thermophoresis (MST) is a rapidly developing bioanalytical technique used routinely for the examination of ligand-target affinity. It has never been used so far for the analysis of acid-base dissociation and the determination of pKa constant. This work is the-proof-of-concept of this new idea. It demonstrates that the pKa values obtained from the thermophoretic data are consistent with the reference methods. As a result, the analytical potential and utility of the MST technology can become even greater, especially if the new detection system of thermophoretic movement will be developed in the future. Even now, taking into account the necessity to use fluorescence, the proposed method may be useful in many respects.
Keywords: MicroScale thermophoresis; acid-base equilibrium; fluorescein isothiocyanate; fluorescence; thermal diffusion; thermodynamics.