Determination of substrate/ligand binding constants from electromotrive force measurements

摘要

An equation, which relates the variations of the standard formal potentials of a redox couple in the presence of variable concentrations of a substrate, S, to the Gibbs energies of binding (to the substrate) of the two forms of the couple, has been obtained. The results have been checked using the data corresponding to the [Fe(CN)(5)4-CNpy](2-/3-) couple in CTACl micellar solutions. It is observed that K (red)< K (ox), in spite of the higher charge of the reduced form. This fact has been explained through consideration of the dielectric saturation at the micelle/water interface.