Protein-film voltammetry: A theoretical study of the temperature effect using square-wave voltammetry

Square-wave voltammetry of surface redox reactions is considered as an adequate model for a protein film voltammetric setup. Here we develop a theoretical approach to analyze the effects of temperature on square-wave voltammograms. The performed simulations address the surface redox reactions featuring slow, modest and fast electron transfer. The theoretical calculations show that the temperature affects the square-wave voltammetric responses in a complex way resulting in a variety of peak shapes. Temperature effects on the phenomena known as "quasireversible maximum" and "split SW peaks" are also analyzed. The simulated results can be used to analyze the redox mechanisms and kinetic parameters of electron transfer reactions in protein-film criovoltammetry and other surface-confined redox systems. Our analysis also shows how "abnormal" features present in some square-wave voltammetric studies can easily be misinterpreted by postulating "multiple species", "stable radicals", or additional processes. Finally we provide a simple algorithm to use the "quasireversible maximum" to determine the activation energy of electron transfer reactions by surface redox systems. (c) 2008 Elsevier B.V. All rights reserved.