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.

No abstract

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.

This work presents the thermal, physical and chemical characterization of Coffee canephora, from littoral region of Cameroon, for their use as reinforcement for polymeric materials. The infrared of coffee hulls shows the presence of a large peak intensity at 3299 cm −1 that can be attributed to O-H stretching group of alcohol (cellulose content in coffee pulp). The intensity 2926 cm −1 can be attributed to C-H stretching group of alkanes or the vibration of methoxy group of lignin. Thermo gravimetric analysis shows that around 440˚C, the biomass has been completely consumed; the temperature profiles show a peak at 86˚C that could correspond to the loss of water as evaporation at a percentage of 8%; the peak at 321˚C is accompanied by a water loss of 64.50%; this temperature is assimilated to the degradation of hemicelluloses; the temperature range from 321˚C to 401˚C is accompanied by a loss of mass of 22.80%, which would be due to the degradation of cellulose. SEM images of the surface of raw coffee hulls, coffee hulls treated with caustic soda respectively clearly reveal gaps between the fibers. The results showed that the incorporation of coffee hulls fiber in LLDPE matrix might result in composites with suitable property application for various industrial fields; especially those that were mechanical features are crucial, such as the replacement of engineering plastics.

In this work fibers derived from coffee, hulls have been incorporated into Linear Low Density Polyethylene (LLDPE). The influence of the filler content on the thermal and physicomechanical properties of the composites obtained was assessed. The results showed that the incorporation of fibers was able to improve the thermostability of LLDPE/Coffee hulls fibers; comparing the treated fiber composite with untreated fiber composites, the chemical treatment reduces by 58.3% the water absorption, while increasing the elongation and tensile strength by about 48% and 17% respectively. Moreover, due to better interfacial interaction induced by MAPE, the corresponding composite exhibited better properties compared to the untreated fiber composite. Results are indicative of the fact that both mercerization and MAPE (coupling agent) have significant positive effects on the fiber-matrix interaction in terms of adhesion, wetting and dispersion, this treatment produced a better fiber distribution and consequently a more uniform composite morphology without voids and gaps between the fibers and the matrix, allowing the possibility to use higher fiber contents (up to 30% wt.) with acceptable mechanical properties.