VOLTAMMETRIC APPLICATION OF ELECTROMODULATED ELECTROREFLECTION ABSORPTION-SPECTROSCOPY - ELECTROREFLECTANCE VOLTAMMETRY AS AN INSITU SPECTROELECTROCHEMICAL TECHNIQUE

It has been demonstrated that the voltammetric in situ application of electromodulated UV-vis reflectance spectroscopy, electroreflectance (ER) voltammetry, is a powerful tool with which to analyze the electrode reaction of an adsorbed species on an electrode surface. The ER response, which in fact originates from the absorbance change with ac modulation of the electrode potential, was theoretically analyzed and simulated as a function of electrode potential. The results of the theory and simulation were compared to the electrode reaction of Nile Blue A adsorbed on a pyrolytic graphite electrode surface. The resulting ER voltammetry was responsive only to the faradaic processes of Nile Blue A adsorbed on a pyrolytic graphite electrode, and its turnover reaction rate was determined to be in the range of 60-120 s-1. It was revealed through ER measurements that the electronic structure as well as the redox reaction mechanism of the adsorbed Nile Blue A on a graphite electrode were significantly different from those of the native dye.