Development of Electrochemical Sensors for Diclofenac Monitoring: A Study of ZnO/BTS Composites

Abstract

Electrochemical sensors (ECS) are increasingly recognized for their exceptional ability to detect and monitor environmental pollutants, offering distinct advantages over traditional analytical methods. By modifying bare electrodes, the key performance attributes of ECS such as selectivity, sensitivity, response time, and portability can be significantly enhanced. Researchers have explored a variety of materials, including noble metals, metal oxides, polymers, and various carbon-based substances, to optimize these sensors for improved analytical performance. This advancement is especially crucial for detecting diclofenac, a widely used anti-inflammatory drug known to pose risks to aquatic ecosystems and human health. In this context, zinc oxide and barium titanate stannate (ZnO/BTS) composites were synthesized through microwave processing of a precipitate to modify the electrode and test its effectiveness as an electrochemical sensor for diclofenac (DCF) detection. Cyclic voltammetry (CV) was employed for the electrochemical quantification of DCF in a three-electrode system consisting of a glassy carbon electrode as the working electrode, a saturated calomel electrode (SCE) as the reference electrode, and a platinum foil as the counter electrode. The ink was prepared by mixing 10 mg of synthesized particles (ZnO/BT, ZnO/BTS5, and ZnO/BTS10) with 1.5 mg of carbon black, 40 μL of 5% Nafion solution, 225 μL of ethanol, and 225 μL of water. CV measurements were conducted in 25 mL of phosphate buffer (0.1 M, pH 7.0), with incremental additions of diclofenac infusion solution (75 mg DCF / 3 mL, Galenika a.d.) ranging from 1 μL to a final volume of 12 μL. All measurements were performed within a potential range of 0.2 to 1 V vs. SCE, at a scan rate of 20 mV⋅s−1.