Ultra-selective detection of Cd2+ and Pb2+ using glycine functionalized reduced graphene oxide/polyaniline nanocomposite electrode

Abstract

An efficient electrochemical sensor with high sensitivity, selectivity and fast detection ability was developed for the trace level detection of Cd2+ and Pb2+ using glycine functionalized reduced graphene oxide/ polyaniline nanocomposite as a recognition layer. The morphological and structural studies of synthesized receptor nanocomposites were verified via X-ray diffraction, Fourier transform infrared spectroscopy, UV/Visible spectroscopy, Raman studies, SEM analysis and BET studies. Electrochemical features were explored via electrochemical impedance spectroscopy and cyclic voltammetry whereas the stripping voltammetric behavior of modified electrodes was analyzed by utilizing square wave anodic stripping voltammetry. The chemical and electrochemical parameters which influence the performance of modified sensors towards the accumulation and stripping of metal ions, for instance, pH of the medium, accumulation potential, scan rate, stripping medium and foreign species were carefully studied to achieve best sensing response. The designated sensor exhibited the excellent sensing properties towards heavy metal ions with quite low limit of detection 0.07 nM for Cd2+ and 0.072 nM for Pb2+ respectively. The proposed methodology allowed a robust and sensitive inspection of Pb2+ and Cd2+ in tap water, making this novel platform a promising candidate for field applications to monitor heavy metal contaminants. Most significantly, this methodology can be applicable for the ultrasensitive detection of other noxious pollutants due to excellent properties of receptor species such as fast electron transfer kinetics, broad surface area, wide conduction path, and exceptional electro-catalytic properties.