Cyclic and Square Wave Voltammetry Analysis of MTZ Using Reactive Electrode Based on Montmorillonite and Na-Alginate

This work describes the elaboration and the electroanalytical tests of a new electrode based on a mixture of graphite and biopolymer-modified montmorillonite nanocomposite. Initially, the nanocomposite was synthesized using sodic montmorillonite (NaMT) and sodium alginate (Naalg) extracted from Tunisian algae. The resulting nanocomposite was characterized by X-ray diffraction (XRD), infrared spectroscopy (UATR), and differential scanning calorimetry (DSC). XRD analysis revealed an increase in the basal spacing d001 and the appearance of reflections (020) and (220) of guluronan groups. Infrared spectra showed characteristic polymer bands such as symmetric and antisymmetric stretching vibrations of the carboxylic group in the nanocomposite spectra indicating the modification. Thermal analysis displayed a shift in the temperature of Naalg decomposition to a higher temperature in the nanocomposite thermogram. The obtained nanocomposite was then used in the development of an electrode. The resulting hybrid electrode was tested for metronidazole (MTZ) analysis using cyclic voltammetry (CV) and square wave voltammetry (SWV). Various parameters including pH, scan rate, MTZ concentration, frequency, etc., were investigated. The results revealed the irreversibility of the studied molecule and indicated that the reduction mechanism involves both diffusion and adsorption behaviors. SWV showed a better sensitivity to detect MTZ than the CV technique. Promising results were obtained, suggesting prospects for this new hybrid electrode.