Use of a Schiff base-modified conducting polymer electrode for electrochemical assay of Cd(II) and Pb(II) ions by square wave voltammetry

The work herein describes the electrochemical detection of heavy metal ions, specifically cadmium and lead. The introduction and modification of functional groups such as Schiff bases leads 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 to detect cadmium(II) and lead(II) ions. The structures and morphologies of the polymer coatings were characterised via Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The electrochemical synthesis and redox state response in monomer-free synthesised films have been studied via 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 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 mu g L-1 and 1.84 mu g L-1, respectively. These findings revealed that modified films can be considered good candidates for application in electrochemical detection devices.

Automated summary

The work discusses the electrochemical detection of heavy metal ions, particularly cadmium and lead, by modifying a platinum electrode with PEDOT/Schiff base polymer coatings. The study investigates the structures and morphologies of the coatings, electrochemical synthesis, redox state response, and the effect of scan rate on the modified electrodes. Results show that the modified films have good potential for use in electrochemical detection devices, with detection limits of 0.95 μg/L for cadmium(II) and 1.84 μg/L for lead(II).