Chronoamperometric Curves Obtained from Optical Absorption Signals

A novel method of obtaining double potential-step chronoamperometric (DSAmp) curves from optical absorption signals was developed. For this purpose, the double potential-step chronoamperometry was used to investigate the first redox processes of genistein on a graphite-wax electrode in a long optical-path thin-layer spectroelectrochemical cell. Double potential-step chronoabsorptometric (DSAbs) data were recorded at the characteristic absorption wavelengths of this system, 259 and 286 nm, respectively. According to the DSAbs data, two DSAmp curves were derived using a self-developed computer program, which represented the transient reaction currents of genistein and its oxidation product in free solution, respectively. Compared with the measured DSAmp curve, the reconstructed DSAmp curves excluded not only the contribution from the species pre-adsorbed on the electrode surface but also the charging current. Accordingly, the contributions of the species in free solution and in adsorbed state to the total redox currents during the potential perturbations can be distinguished.