Voltammetric Characterization of Carbon Paste Electrodes with a Nonconducting Binder. Part I: Evidence of the Influence of Electroactive Species Dissolution into the Paste on the Voltammetric Response

Abstract

The voltammetric characterization of ferrocene confined within a carbon paste electrode (CPE) with nonconducting binder (Nujol or silicon oil) was performed. The voltammetric behavior depends directly on the way in which the electroactive species were introduced into the paste: as a solid or previously dissolved into the binder. These two forms were found to contribute in the electrochemical process in a single voltammetric peak. Variations in the potential sweep rate , type of binder (meaning changes in ferrocene solubility), the amount of binder in the paste, and also the amount of the electroactive species affect the shape of the voltammetric curves obtained. This enables us to distinguish between the contributions of the solid and dissolved forms of ferrocene in the voltammetric response. From this study, it is established that the ferrocene oxidation in CPE was limited by diffusion, taking place in a layer beyond the electrode-electrolyte interface, resulting from the dissolution of ferrocene within the binder. The existing controversy reported for voltammetric studies of ferrocene in CPE could be explained by the presence of two different ferrocene species involved in the oxidation process.

On the electrochemistry of dopamine in aqueous solution. Part I: The role of [SDS] on the voltammetric behavior of dopamine on a carbon paste electrode

“…A typical three electrode cell was used where a carbon paste electrode, CPE, was the working electrode. The CPE was prepared as usual, by mixing the Johnson Matthey 1 lm, 99.9% graphite powder with nujol as indicated elsewhere, Ramírez-Silva et al [24,25]. A platinum wire (BAS MW-1032) was the counter electrode, while saturated Ag/AgCl (BAS MF-2052) was the reference electrode, against which all potentials (E) reported in this work were measured.…”

Taking advantage of CTAB micelles for the simultaneous electrochemical quantification of diclofenac and acetaminophen in aqueous media

“…Electric contact was attained soldering a Pt wire to an external Cu connector; further details can be found in Ramírez et al. 22,23 3 Results and discussion Fig. 1 shows a linear predominance zones diagram constructed following the methodology proposed by Rojas-Hernández et al, [24][25][26][27] for DCF, Fig.…”

Electrochemical Oxidation of 4-Chlorophenol Over a Carbon Paste Electrode Modified with ZnAl Layered Double Hydroxides

“…A typical three-electrode electrochemical cell was used, with either CPE or CPE/ZnAl-LDH as working electrode. The manufacture of the actual base of the working electrode fol-lowed the method published elsewhere by Ramírez-Silva et al [11,12]; a Pt wire served as counter electrode, while the usual Ag/AgCl/KCl(aq,sadt) served as reference electrode. The electrochemical oxidation of 4cp was analyzed out by means of cyclic voltammetry, CV, with KCl (Mallinckrodt 99.7%) as supporting electrolyte and the Potentiostat/Gavanostat PG-STAT 100 AUTOLAB.…”