For each redox couple, the response obtained in cyclic and square wave voltammetries can be fitted satisfactorily with the four-parameter asymmetric MH model. From the fitting of the voltammograms the values of the kinetic parameters are extracted and analyzed in terms of physical properties of the electroactive species. A comparison of the asymmetric model against the simpler, phenomenological Butler-Volmer (BV) approach is discussed, as well as a possible physical interpretation for the BV transfer coefficient.