Electrochemically Reduced Graphene Oxide Pencil-Graphite in situ Plated Bismuth-film Electrode for the Determination of Trace Metals by Anodic Stripping Voltammetry

摘要

An electrochemical platform was developed based on a pencil-graphite electrode (PGE) modified withelectrochemically reduced graphene oxide (ERGO) sheets and in conjunction with an in situ platedbismuth-film (ERGO-PG-BiE). The ERGO-PG-BiE was used as a sensing platform for determining2+ 2+ 2+ Zn , Cd and Pb by square wave anodic stripping voltammetry (SWASV). ERGO sheets weredeposited on to pencil-graphite electrodes by cyclic voltammetric reduction from a graphene oxide(GO) solution. The GO, with flake thicknesses varying between 1.78 to 2.10 nm (2 sheets) wascharacterized using FT-IR, HR-SEM, HR-TEM, AFM, XRD and Raman spectroscopy. Parametersinfluencing the electroanalytical response of the ERGO-PG-BiE such as, bismuth-film concentration,deposition potential, deposition time and rotation speed were investigated and optimized. The ERGO- -1 -1 PG-BiE gave well-defined, reproducible peaks with detection limits of 0.19 g L , 0.09 g L and-1 2+ 2+ 2+ 0.12 g L for Zn , Cd and Pb respectively, at a deposition time of 120 seconds. For real sampleanalysis, the enhanced voltammetric sensor proved to be suitable for the detection and quantitation of-1 -1 heavy metals below the US EPA prescribed drinking water standards of 5 mg L , 5 g L and 15 g-1 2+ 2+ 2+ L for Zn , Cd and Pb respectively.