Fabrication of Ni0.5Mg0.5Fe2O4/Reduced Graphene Oxide Based Electrochemical Sensor for the Detection of Lead

Abstract

Lead (Pb) is considered as one of the main toxic heavy metal that causes environmental contamination and certain severe problems to the human health. Therefore, trace level detection of lead in the environment is very much required. In this work, a highly sensitive sensor based on interdigitated electrode modified by sensing materials like Ni0.5Mg0.5Fe2O4 ferrites, graphene oxide and Ni0.5Mg0.5Fe2O4/rGO nanocomposite have been successfully fabricated for the detection of Pb. Scanning electron microscopy and X-ray diffraction characterization techniques have been performed for the morphological and structural studies of the sensing materials. SEM results show that the average particle size to be 20nm with no agglomeration and XRD results justify the formation of required sensing materials as all the relevant peaks are present. Linear sweep voltammetry, cyclic voltammetry and electrochemical impedance spectroscopy techniques have been used to observe the electrochemical response of fabricated sensor towards Pb2+ ions. Results reveal that IDEs modified by Ni0.5Mg0.5Fe2O4 ferrites show very low response towards Pb2+ ions while graphene oxide and Ni0.5Mg0.5Fe2O4/rGO nanocomposite modified IDEs show higher response when exposed to Pb2+ ions. Among the three sensing materials used, Ni0.5Mg0.5Fe2O4/rGO nanocomposite modified IDEs has higher sensitivity. The sensitivity achieved by using Ni0.5Mg0.5Fe2O4/rGO nanocomposite as a sensing element is 0.000389 μA ppb-1 and limit of detection (LOD) obtained is 7.06 ppb, which is much below the threshold limit (10ppb) set by the world health organization (WHO).