A novel electrochemical sensor based on calixarene functionalized reduced graphene oxide: Application to simultaneous determination of Fe(III), Cd(II) and Pb(II) ions.

A glassy carbon electrode (GCE) modified by calixarene functionalized reduced graphene oxide (CA/RGO) has been fabricated and utilized in this study for simultaneous voltammetric detection of several metal ions, Fe(II), Cd(II) and Pb(II), in aqueous solution. The CA/RGO nanocomposite was characterized in surface and electrochemical properties using scanning electron microscopy (SEM), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Raman spectroscopy and electrochemical impedance spectroscopy (EIS). The CA/RGO coating significantly improves the sensitivity of electrochemical responses and separation of heavy metals. The electrochemical oxidation of Fe(III), Cd(II), and Pb(II) was performed by square wave voltammetry (SWV). The metal ions, Fe(III), Cd(II), and Pb(II), gave a linear relationship with their concentrations at 1.0×10-10 -1.0×10-8 M on the CA/RGO/GCE. The detection limits of the metal ions were found to be similar at 2.0×10-11 M. A good recovery was also obtained for practical use of the CA/RGO/GCE in pharmaceutical formulation.