Processes during anodic stripping voltammetry determination of lead in the presence of copper on a solid electrode modified with 2,2′-bipyridyl in polyaniline

Preparation of nano-sized Pb2+ imprinted polymer and its application as the chemical interface of an electrochemical sensor for toxic lead determination in different real samples

In this work, a new nano-structured ion imprinted polymer (IIP) was synthesized by copolymerization of methacrylic acid-Pb(2+) complex and ethylene glycol dimethacrylate according to the precipitation polymerization. Methacrylic acid acted as both functional monomer and complexing agent to create selective coordination sites in a cross-linked polymer. A carbon paste electrode modified with IIP-nanoparticles was used for fabrication of a Pb(2+) sensitive electrode. Differential pulse stripping voltammetry method was applied as the determination technique, after open circuit sorption of Pb(2+) on the electrode and its reduction to metallic form. The IIP modified electrode showed a considerably higher response, compared to the electrode embedded with non-imprinted polymer (NIP). This indicated that the suitable recognition sites were created in the IIP structure in the polymerization stage. Various factors, effective on the response behavior of the electrode, were investigated and optimized. The introduced sensor showed a linear range of 1.0 × 10(-9) to 8.1 × 10(-7)M and detection limit of 6.0 × 10(-10)M (S/N=3). The sensor was successfully applied for the trace lead determination in different samples.

Square wave anodic stripping voltammetric determination of Pb2+ using acetylene black paste electrode based on the inducing adsorption ability of I−

Herein, a sensitive and simplified electrochemical method was proposed for the determination of trace levels of Pb2+ by anodic stripping voltammetry (ASV) based on the inducing adsorption ability of I- toward Pb2+. In the presence of low concentration of I-, Pb2+ was induced to accumulate onto the acetylene black (AB) paste electrode surface, and then reduced at -0.90 V. During the following square wave sweep from -0.90 to -0.30 V, the reduced Pb was oxidized, resulting in a sensitive and well-shaped stripping peak at -0.56 V. Further studies indicate that low concentration of I- significantly enhances the sensitivity of determination of Pb2+. After all the experimental parameters were optimized, a novel and sensitive method was developed for the electrochemical determination of Pb2+. The linear range is found to be from 2.0 x 10(-8) to 4.0 x 10(-6) mol L(-1), and the lowest detectable concentration is estimated to be 6.0 x 10(-9)mol L(-1). This newly proposed method was finally demonstrated with water samples. Otherwise, the anodic stripping responses of Pb2+ on AB paste electrode and graphite paste electrode were compared.