Halim-mediated zinc oxide electrochemical sensor for copper detection in aqueous solution

• Published in: Journal of materials science. Materials in electronics 2024-05, Vol.35 (15), p.1029, Article 1029
• Main Authors: Vijayalakshmi, K., Radha, S., Muthumeenakshi, K., Sreeja, B. S.
• Format: Article
• Language: English
• Subjects: Aqueous solutions; Bismuth; Characterization and Evaluation of Materials; Chemical sensors; Chemistry and Materials Science; Copper; Correlation coefficients; Crystallites; Electrodes; Electrolytic analysis; Field emission microscopy; Graphite; Materials Science; Optical and Electronic Materials; Potassium chloride; Scanning electron microscopy; Scanning transmission electron microscopy; Sensors; Synthesis; Transmission electron microscopy; Voltammetry; Water sampling; Zinc oxide; Zinc oxides
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-024-12819-7

In this novel effort, electroanalysis of copper ions in water samples was successfully achieved by employing a green, sustainable, and low-cost synthesis method using zinc oxide (ZnO) nanoparticles synthesized with Halim seed extracts, which were drop-casted on a graphite electrode. The seed extract acts as an eco-friendly, non-toxic reducing and capping agent, providing a facile synthesis process. The crystallite structure, morphological structure, elemental mapping, and composition were investigated and confirmed using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), and Energy dispersive X-ray microanalysis (EDX). The modified graphite electrode sensing behavior was examined using cyclic voltammetry (CV) in the presence of potassium chloride (KCl) solution. The sensor was subjected to differential pulse voltammetry (DPV) for copper quantification in water. Optimized result was achieved at pH = 7.5. The limit of detection (LOD) of 80 ppb and limit of quantification (LOQ) of 200 ppb were ascertained from the calibration plot of DPV analysis. The sensor was able to adsorb copper ions selectively in the presence of cations such as zinc, lead, cadmium, bismuth, and nickel and anions such as chloride, sulfate, and hydroxide ions. The green sensor exhibited a linearity from 0 to 1 ppm with correlation coefficient of 0.99. The stability of the sensor ensures feasibility of fabrication for real-time analysis.