Electrochemical Oxidation of the Paracetamol in its Commercial Formulation on Platinum and Ruthenium Dioxide Electrodes

Pt and RuO2 electrodes have been prepared thermally at 400 degrees C on titanium substrates. The physical and electrochemical characterization showed that the surface of the platinum electrode is smooth, compact and almost homogeneous and that of RuO2 is rough with a mud cracked structure. The voltammetric investigations revealed that the oxidation of the paracetamol occurs on both the prepared electrode. That organic oxidation occurs via a process that involves a direct electron transfer at the surface of the electrode and by an indirect oxidation process via species and possibly via other in situ redox species. On both the electrodes, the paracetamol oxidation process is diffusion controlled. In the presence of Cl-, NO3-, or PO43- the oxidation of paracetamol still occurs via a direct electron transfer in the water stability domain and via an indirect oxidation routes in the higher potential domain by oxidative species resulting from the oxidation of Cl-, NO3-, or PO43-. The addition of such ions in the electrolyte increases the kinetic of the paracetamol oxidation. This increase is low for all the ions on RuO2 electrode but it is high with Cl- or NO3- on Pt and low with PO43-. pH studies have revealed that the protonation form of the molecule undergoes a rapid oxidation than the deprotonated form on Pt. On RuO2, the pH influence is very low compared to platinum electrode.