The aim of this work is to prepare and characterize a carbon-clay paste electrode doped with Titanium Oxide (CPEA/TiO 2 ). This electrode is used to study the electrochemical behavior of drugs such as Chloroquin, Azithromycin and Hydroxychloroquin. The morphological, structural and functional characteristics of this electrode were carried out using X-ray diffraction (XRD), selected area electron diffraction (SAED), scanning electron microscopy (SEM), Fourrier transform infrared spectroscopy (FTIR). The electrochemical characterization was made by Cyclic Voltammetry (CV) in the potential range [-0.1V; 0.9V], in a phosphate buffer solution (0.1M; pH = 6.4); focused on the detection of an inorganic complex (ion [Fe(CN) 6 ] 3-(1mM)). The application was made focused on the detection of organic macromolecules such as azithromycin (AZI), chloroquin (CHL) and hydroxychloroquin (HYC). CPEA/TiO 2 was then subjected to electroanalysis in the same concentrations of the combinations AZI+CHL and AZI+HYC. However, in the presence of analyte the phenomena are irreversible with a dominance of oxidation phenomena. The electroactivity of the drugs used initially concerns the hydroxyl groups, observed around 0.050V (oxidation potential of the hydroxyl function in an intermediate form) and 0.560V (oxidation potential of the intermediate and in the carbonyl group). Secondly, the electro activity of the tertiary amine is highlighted by the potential value of 0.690V (attributable to the oxidation of the tertiary amine into an ammonium hydroxyl derivative). Current densities are more pronounced, which suggests a new molecule with significant electro activity. The oxidation mechanism is proposed. The electroactivity of the excipients (Lactose and Starch) used in these drugs is not negligible and evolves when going from one drug to two. However, the excipients are less noticeable in the AZI+HYC combination than in AZI+CHL.

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Calcinated and acidified clay modified carbon graphite electrode was deployed in the simultaneous evaluation of traces of Pb2+ and Cd2+ in solution. After 5 minutes of accumulation in the circuit, the sensitivity of the electrode was evaluated in a solution of Na2SO4 (0.1 M) by square wave voltammetry on the one hand with Pb (II) and on the other hand with Cd (II). Several experimental conditions such as the composition of the carbon clay paste, the effect of preconcentration time, the sweeping speed, concentration effect, media pH, and interference ionic response to the electrochemical response of the working electrode were examined. It was observed that, after 5 minutes of preconcentration, detection limits of 0.15513 μmol·L−1 and 0.24227 μmol·L−1 were obtained for Pb2+ and Cd2+ in the electrolyte solution and 0.08438 μmol·L−1 and 0.46522 μmol·L−1, respectively, when tap water was used. The detection was effective by square wave voltammetry with a more intense current density with respect to lead.