Anodic Adsorptive Stripping Voltammetric Determination of Rafoxanide on Glassy Carbon Electrode

Abstract

Background: Rafoxanide (RFX) is an active agent against Fasciola hepatica, but it is prohibited for treatment of dairy animals whose milk is provided for human consumption. Objective: A reliable, fast, and simple method needs to be developed to monitor RFX residues in milk samples before distribution to consumers. Methods: In this work, the electrochemical oxidation of RFX was studied at glassy carbon electrodes (GCE) in Britton-Robinson buffer (BR) solutions over the pH range 2.0-12.0 using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The oxidation of the drug was accomplished in a single irreversible, adsorption-controlled step within the pH range 4.0-9.0. Therefore, the application of GCE for a sensitive and selective quantification of RFX by adsorptive stripping voltammetry was reported. The accumulation of the analyte was performed in Britton–Robinson buffer (pH 5.0) at a potential of -0.3 V (vs. Ag-AgCl-KClsat) for 300 s and the measurement was carried out, after medium exchange, in BR solution of pH 7.0 using DPV. Result and Conclusion: This format was satisfactorily applied for the determination of RFX in bovine milk. Limit of detection (LOD) of 1.25 µg kg -1 of milk and mean recoveries of 97.8 to 107.5% were achieved.