An electrochemical detection of cadmium (II) and lead (II) ions using a polymer-modified electrode with a Schiff base by square wave voltammetry

Abstract

The work herein concentrates on the electrochemical detection of heavy metal ions, specifically cadmium and lead ions. The introduction and modification of functional groups such as Schiff bases had led to an enhanced sensitivity of the electrode to analytes. In this study, a platinum electrode has for the first time been modified with poly(3,4- ethylenedioxythiophene) (PEDOT/Schiff base) in CH2Cl2 containing Bu4NPF6 for use to detection cadmium (II) and lead (II) ions. The structure and morphology of the polymer coatings were characterised by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), respectively. The electrochemical synthesis and redox state response in monomer-free synthesised films have been studied by cyclic voltammetry. Moreover, the effect of scan rate on the electrochemical behaviour of the modified electrodes was also studied. The voltammetric findings have been used to calculate the surface coverage required for the polymer films and the stability of polymer electrodes in the monomer-free solutions. Square wave voltammetry (SWV) was applied for the determination of cadmium (II) and lead (II) ion concentrations and to assess the effects of pH on aqueous samples. The limits of detection for the modified electrode for cadmium (II) and lead (II) were found to be 0.95 μg L-1 and 1.84 μg L-1, respectively. These findings revealed that modified films can be considered good candidates for application in electrochemical detection devices