DERIVATIVE LINEAR SWEEP AND DERIVATIVE CYCLIC VOLTABSORPTOMETRY OF THE LONG-PATH-LENGTH SPECTROELECTROCHEMICAL CELL - THE SINGLE REVERSIBLEELECTRODE-REACTION

This paper presents the theory of derivative linear sweep and derivati ve cyclic voltabsorptometry (DLSVA and DCVA) of the long-path-length s pectroelectrochemical (SEC) cell for the single reversible electrode r eaction. Assuming that only the oxidized species (Ox) absorbs at the m easurement wavelength initially, the first- and second-derivative opti cal responses for two cases, i.e. thin layer diffusion for Ox + ne- ha lf arrow right over half arrow left Red (reduced species) or Red half arrow right over half arrow left Ox + ne- and semi-infinite diffusion for Ox + ne- half arrow right over half arrow left Red or Red half arr ow right over half arrow left Ox + ne-, have been discussed via digita l simulation, etc. All types of theoretical behaviour have been compar ed with that of the optically-transparent electrode (OTE). The results show that DLSVA and DCVA of the long-path-length SEC cell are more se nsitive (by several decades or more) than those of the OTE. The theore tical results are verified experimentally by the well-characterized re versible electrochemical system Fe(CN)63-/Fe(CN)64- in 0.5 M HNO3 + 0. 5 M glycine buffer.