Electrochemical determination of cadmium ions in biological and environmental samples using a newly developed sensing platform made of nickel tungstate-doped multi-walled carbon nanotubes

Abstract

Simple and rapid analysis of cadmium ion in environmental and biological samples is of great importance due to the severe toxicity caused by this heavy metal. In the present work, nickel tungstate (NiWO4) dispersion was mixed with multi-walled carbon nanotubes (MWCNTs) to obtain a homogenous composite of (NiWO4/MWCNTs) which was assigned as carbon paste electrode modifier. The composite was fully characterized using various characterization techniques including X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Thermo-Gravimetric Analysis (TGA) and Fourier Transform InfraRed (FTIR). The electrochemical redox reactions of cadmium (II) ions at the modified electrode interface were investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and linear sweep voltammetry (LSV). Effective parameters on the electro-analysis assay performance including the electrode composition, types of electrolyte, scan rate and pH were tested to achieve the best effective optimum conditions. Accordingly, a linear relation of cadmium ions was achieved in the concentration range 50–450 µM with limit of detection of 0.12 µM. Besides, the proposed electrode was successfully used to monitor trace amounts of cadmium ions in various real samples.Graphical abstractSchematic illustration of synthesis process of NiWO4/MWCN nanocomposite and its application as high-performance cadmium ion sensors