A highly sensitive electrochemical sensor for Cr6+ ions detection using Ag NPs/rGO/quercetin modified glassy carbon electrode for water applications

Abstract

Heavy metals possess some serious hazardous influence on the environment as well as on human health. Monitoring of Cr6+ ions using the electrochemical sensing method proves to be an effective analytical tool and has an edge over the other conventional technologies. The glassy carbon electrode used in this study has its surface modified with highly sensitive silver nanoparticles, conductive 2-dimensional carbon material, and a metal chelating bio-compound prepared to significantly impact the selectivity and sensing of metal ions in the electrochemical determination. Applying the green chemistry principle, Graphene Oxide is reduced and functionalized simultaneously using a natural flavonoid called quercetin. Turkevich method was used to synthesis Silver nanoparticles. A novel composite is prepared by taking these compounds in a 1:1:2 ratio. The working electrode's surface was modified using this Ag NPs/Q-rGO composite and used in the analysis of Cr6+ ions. The physio-chemical characterization of the synthesized Ag NPs/quercetin-rGO composite was carried out. The surface morphology of the novel composite was observed. The cyclic voltammetry technique was used for electrochemical characterization. The monitoring of the Cr6+ metal ions using the Ag NPs/Q-rGO electrode was done with differential pulse voltammetry technique. The cyclic voltammogram for the Ag NPs/Q-rGO showed two anodic peaks at Epa1 = 0.28 V, Epa2 = 0.38 V, and one cathodic peak was seen at Epc = 0.14 V. Analytical parameters like the effect of electrolytes and the effect of pH were optimized. The results obtained from DPV experiments showed that the Ag NPs/Q-rGO electrode is efficient enough to sense the Cr6+ ions. Interpretation from the Linear plot helped in determining the LOD and LOQ of Cr6+ ions in the system which was found to be 0.07 μgL−1 and 0.224 μgL−1 respectively.