Determination of Association and Dissociation Rate Constants in an Inclusion Complex System between Thymol and Sulfated-β-cyclodextrin by Moment Analysis - Affinity Capillary Electrophoresis

Abstract

Abstract The combination of moment analysis (MA) theory with affinity capillary electrophoresis (ACE) leads to a new method (MA-ACE) for the kinetic study of intermolecular interaction. The reaction rate constants, i.e., association (ka) and dissociation (kd) rate constants, can be analytically determined by the MA theory from the first absolute and second central moments of the elution peaks measured by ACE. In order to verify the validity of the MA-ACE method, the values of ka and kd were analytically determined for the formation and dissociation of the inclusion complex between thymol and sulfated-β-cyclodextrin. The resulting values of ka and kd were comparable with those in our previous study, which were determined by chromatographic capillary electrophoresis with the MA theory. It was demonstrated that the MA-ACE method was effective for the kinetic study of intermolecular interactions. The rate constants can be analytically determined with no immobilization and no chemical modification, i.e., fluorescence labelling, of solute and ligand molecules.