Electrochemical sensor for the determination of ketoconazole based on gold nanoparticles modified carbon paste electrode

The present research work is devoted to a carbon paste electrode modified with gold nanoparticles for the detection of low concentration of ketoconazole (KCZ). A simple preparation procedure for gold nanoparticles (AuNPs) was employed, using an alkaline solution of Pamoic acid (PA) (4,4′-methylene-bis (3-hydroxy-2-naphthalene carboxylic acid)). Since PA is insoluble in water, it can only be dissolved in alkaline media to act as both a capping and reducing reagent to form the AuNPs. Thus, monodispersed, stable, carboxylate-functionalized AuNPs were synthesized without applying thiol derivatives. KCZ was electrochemically studied using differential pulse voltammetry, square wave voltammetry and cyclic voltammetry on the modified carbon paste electrode surface. Under optimized conditions, at pH 4.0 of 0.5 M phosphate buffer solution (PBS), a linear response range for ketoconazole from 1.0 to 80.0 μmol L⁻¹ was achieved with a detection limit (LOD) of 0.1 μmol L⁻¹.