Electrochemical behavior and voltammetric determination of antibiotic drug Nifuroxazide in the pharmaceutical formulation at boron-doped diamond electrode surface

In this work, the electrochemical sensing of Nifuroxazide (NFX) was assessed utilizing a boron- doped diamond (BDD) electrode that underwent electrochemical pretreatment, enhancing its surface activity. Cyclic voltammograms of NFX revealed single, well-defined, irreversible peaks at 0.94 V (vs. Ag/AgCl) in a 0.04 M Britton-Robinson (BR) buffer solution at pH 6.0. The oxidation peaks of NFX were found to be pH-dependent across a range from 2.0 to 12.0. Introducing the cationic surfactant cetyltrimethylammonium bromide (CTAB) into the supporting electrolyte increased the anodic peak currents of NFX. Under optimized conditions, a linear relationship was established for NFX quantification in 0.04 M BR buffer solution (pH 6.0) containing 2×10-4 mol L-1 CTAB at +1.02 V (vs. Ag/AgCl), using an open-circuit condition during a 30-second accumulation step. The linear range spanned from 0.05 to 2.0 μg mL-1 (1.8×10-7 – 7.2×10-6 mol L-1 ), with a detection limit of 0.013 μg mL-1 (4.7×10-8 mol L-1 ). This method was successfully applied to determine the NFX concentration in its commercial pharmaceutical formulation.