Quantitative Analysis of Pb(II) Based on Differential Pulse Anodic Stripping Voltammetry and IIP-Carbon Paste Electrodes

It is well known that Pb(II) is considered a highly toxic metal. The slight difference between toxic and permissible levels in drinking water is a matter of concern; therefore, highly sensitive and selective techniques have been proposed for quantification, such as the electrochemical ones. In this work, an easy, simple, low-cost, and high selective sensor based on carbon paste electrodes (CPE) and ion-imprinted polymers (IIP) is proposed for Pb(II) analysis in real water samples. Recognition cavities, selective to Pb(II), were synthesized based on a cross-linked polymer using vinyl pyridine. A modified CPE was constructed by a mixture of graphite powder, IIP, and paraffin oil. By voltammetry studies, a notable difference was observed in the electrochemical response of the electrodes modified with IIP and those with non-imprinted polymer (NIP), confirming the existence of the recognition cavities in the IIP. The construction and analysis parameters related to the analytical response of Pb(II) (anodic current intensity of stripping voltammetry), were optimized; the selectivity was also studied considering potential interference ions. A linear concentration range from 3.3 mg l(-1) to 33 mg l(-1) and a limit of detection of 0.99 mg l(-1) were achieved. Pb(II) was successfully quantified in real complex samples without previous treatment.