Development of an Electroanalytical Method for Ronidazole Determination in Environmental and Food Matrices Using Boron-Doped Diamond Electrode

A novel electroanalytical approach is presented for the determination of ronidazole in environmental and food matrices by applying a cathodically pretreated boron-doped diamond electrode and the square-wave adsorptive cathodic stripping voltammetry technique. From the studies of cyclic voltammetry to investigate the electroactivity of the ronidazole molecule, the occurrence of an irreversible cathodic process was verifed, which was more effciently detected using the cathodically pretreated boron-doped diamond electrode compared to the anodically pretreated electrode. Still on the electrochemical response of ronidazole, the effects of pH and scan rate were studied and, its apparent diffusion coeffcient was determined by chronoamperometry (8.20 × 10-⁶cm²s^-1). Under optimal experimental conditions, the analytical curve obtained for ronidazole was linear in two concentration ranges (12.70 to 63.40 µmol L^-1 and 76.04 to 126.2 µmol L^-1), with a limit of detection of 2.55 µmol L^-1. For intra- and inter-day repeatabilities, relative standard deviations of only 2.7 and 3.5% were verifed, which demonstrated the stable analytical response of the electrode. Recovery percentages ranging from 96 to 100% were achieved in the analysis of natural water and whole milk samples. Therefore, the proposed electroanalytical method shows satisfactory analytical performance towards ronidazole determination in varied matrice samples.

Keywords:
emerging contaminant; square-wave voltammetry; nitroimidazoles; boron-doped diamond electrode; water samples; milk analysis