Concentrations of electroactive solutes, during cyclic and other voltammetries, at points away from the electrode surface. 1. Fundamental relationships and their validation

There are circumstances in which it is useful to know the concentration, or its gradient, of an electroactive product or reactant at some distance fro m an electrode, Here it is demonstrated that this information is available, in principle, under conditions of semiinfinite planar diffusion, provided that the surface concentration and/or the current are known as functions of time. Several methods orf calculation are explored, using the example of l inear sweep voltammetry, Some of these methods rely on analytical formulati ons; others are purely numerical. Concordance of the results of the various methods provides validation of all, A method based on the convolution of t he current is especially versatile.