Use of the ferrocene oxidation process to provide both reference electrodepotential calibration and a simple measurement (via semiintegration) of the uncompensated resistance in cyclic voltammetric studies in high resistance organic solvents

Because of its presumed ideal reversible behavior, the oxidation of ferroce ne is widely used in cyclic voltammetric studies in highly resistive organi c solvents as a means of reference electrode potential calibration. In this study, it is shown that a good estimate of the uncompensated resistance va lue, needed for reference potential correction and also frequently an input parameter in simulation of the theory, can be obtained simultaneously with the ferrocene reference potential measurement using a simple analysis base d on the semiintegral, Application to cyclic voltammetric oxidation of ferr ocene in dichloromethane (0.1 M NBu4PF6), under conditions where uncompensa ted resistances of similar to 2.5 k Omega are encountered, is used to illus trate the fidelity of the semiintegral method of analysis. Inclusion of thi s estimated resistance value as the input parameter in a commercially avail able digital simulation package confirms that the oxidation of ferrocene in dichloromethane represents a close-to-ideal diffusion-controlled reversibl e process. However, use of the semiintegral method of data analysis also en ables detection of subtle forms of nonideality encountered with the ferroce ne oxidation process in other media where kinetically controlled adsorption of the ferricenium cation may occur.