Sensitive electrochemical sensor based on hybrid material F-doped carbon quantum dots (Cdots) and NiO nanoparticles: detection of ketoconazole in pharmaceutical formulations and tap water samples.

This study presents a novel electrochemical sensor for ketoconazole determination, developed using an advanced hybrid material composed of fluorine-doped carbon quantum dots (F-Cdots) and nickel oxide nanoparticles (NiONPs) to modify a glassy carbon electrode (GCE). The redox behavior of the modified electrode was evaluated using cyclic voltammetry, revealing an irreversible oxidation peak at 0.59 V, associated with the transfer of a single electron. The modified sensor exhibited a performance approximately 50% higher than that of the unmodified GCE. Square wave voltammetry was optimized for quantification, with the best results obtained in 0.1 M phosphate buffer solution (PBS) at pH 9. The sensor exhibited a low detection limit of 7.12 nmol L⁻¹ and a quantification limit of 23.49 nmol L⁻¹. A strong linear response (r = 0.999) was observed over a ketoconazole concentration range from 0.037 to 11.13 µmol L⁻¹. Its wide linear range represents a key advantage, increasing practical applicability and versatility in various analytical scenarios compared to previous methods. The sensor was successfully applied to pharmaceutical formulations and tap water samples, achieving recovery rates between 88.8 and 103.6%. Furthermore, it demonstrated minimal interference from other compounds, highlighting its high selectivity and robustness for real applications in pharmaceutical quality control and environmental monitoring.