Moment theory of affinity capillary electrophoresis for analysis of reaction kinetics of intermolecular interactions

A theoretical basis for affinity capillary electrophoresis (ACE) was systematically developed by applying the moment theory to the study on intermolecular interactions between solute (S) and ligand (L) molecules to form complex (X). Moment equations were developed for both complete filling and partial filling ACE systems, in which SL_m or S_nL forms as X. They are effective for the determination of equilibrium and kinetic constants of association between S and L and dissociation of X from the first absolute and second central moments of elution peaks measured by ACE. In order to demonstrate their effectiveness, simulative calculations of partial filling ACE behavior was conducted by assuming the stoichiometry of 1:1 between S and L. Because partial filling ACE systems are classified into five categories based on experimental conditions, calculation results for all the five cases are explained. The combination of ACE and moment theory is effective because there are some advantages concerning the accurate analysis of intermolecular interactions. The results of this study provide an opportunity for the study on intermolecular interactions to many researchers because CE is already versatile.