A new voltammetric sensor for metronidazole based on electro catalytic effect of Al2O3 modified carbon graphite. Application. Urine, tap water and river water

Abstract Metronidazole is an anti-parasitic drug of the nitro-5-imidazole class, discovered in 1959. The objective of this research was to construct a highly sensitive sensor to detect Metronidazole in real samples. We elaborated a carbon paste electrode modified with Al2O3 microparticles that are hydrothermally formed on the graphite carbon sheet. As a working electrode, the different experimental parameters have been optimized. The electrochemical behavior of the antibacterial metronidazole was examined by the proposed sensor is perfectly irreversible. This device presents an excellent electro-catalytic activity for metronidazole reduction, as shown by a peak of maximum metronidazole reduction localized at the position of −0.61v /µAl2O3@CPE relative to Ag/AgCl. The pH effect of PBS shows that the number of protons and electrons was equal. The diffusion coefficient and the electro-catalytic rate constant were evaluated at 6.34x10-4 cm2/s and 3.4 cm3/mol/s respectively. The morphology and chemical composition of the prepared paste have been characterized by SEM, X-ray diffraction and IR, the size of Al2O3 microparticles is about 4.45 µm, the calibration curve has been plotted in the concentration range of 10−3 to 0.5 × 10−6 M using the Differential pulse voltammetry method. The limit of detection (LOD) and limit of quantification (LOQ) were calculated to be 0.253 × 10−6 M and 0.844 × 10−6 M, respectively. The applicability of our µAl2O3@CPE sensors in the determination of Metronidazole in real samples contaminated with the Metronidazole antibacterial, including tap water, river water and urine. The electro-analysis results obtained show a very satisfactory recovery rate of more than 94%.