Ion-imprinted polyaniline-based polymer for selective electrochemical detection of cadmium

An electrochemical sensor based on ion-imprinted functionalized polyaniline has been fabricated and tested for the electrochemical sensing of cadmium in aqueous solution. The synthesis of the polymer was started by copolymerizing anthranilic acid and 2-(1H-benzimidazol-2-yl) aniline in the presence of Cd2+ ions as the target analyte and followed by acid leaching out the analyte to obtain the ion-imprinted polymer (IIP). The synthesized IIP was examined for its structural, crystallographic and morphological cha­racteristics using Fourier-transform infrared spectroscopy, X-ray diffraction analysis and field-emission scanning electron microscopy. The IIP has been used to modify a carbon paste electrode (CPE), and the IIP-modified CPE was tested for the sensitive and selective detection of Cd2+ ions in aqueous solution. The key electrode preparation parameters, i.e. Cd deposition potential, pH of deposition solution, deposition time, and thickness of active layer, were optimized using pulse voltammetric stripping analysis to achieve maximum performance. Electrochemical investigations with the optimized IIP-modified CPE revealed a high sensitivity for Cd2+ ions as well as a high selectivity in the presence of potentially interfering ions. Reproducibility and repeatability of the electrode were assessed and found to be satisfactory.