Voltammetry of heterogeneous labile metal-macromolecular systems for any ligand-to-metal ratio - Part II. Obtaining the binding curve from the normalised limiting currents

This paper discusses the determination of the binding curve from limiting c urrents. Recently, an analytical approximation for the limiting current in terms of the bulk complex concentration has been proposed. This expression is so simple that it can be easily inverted allowing the computation of the binding curve from normalised limiting currents corresponding to the titra tion of a fixed amount of ligand with metal. Different complexation models with discrete or continuous affinity spectra are analysed. An affinity wind ow associated with a given titration is recognised and it is shown that an accurate binding curve can be obtained by combining the meaningful affinity windows of several titration experiments with different amounts of ligand. The global aim of the paper is to enhance the possibilities of binding stu dies from voltammetric limiting currents providing some criteria to succeed in this analysis. (C) 2001 Elsevier Science B.V. All rights reserved.