Electrochemical sensor based on lead ion-imprinted polymer particles for ultra-trace determination of lead ions in different real samples

Abstract

In this paper, a self-manufactured lead(II)-selective electrode, which was based on the use of lead(II) ion imprinted polymer particles (IIPs) to detect lead ions, was studied using differential pulse voltammetry. The synthesis and preparation of the IIPs was by precipitation polymerization with methacrylic acid (function monomer and lead-binding ligand), ethylene glycol dimethacrylate (the cross-linker) 2,2-azobisisobutyronitrile (the initiator) and lead ions (the template ion) in an acetonitrile solution. The IIPs were prepared to establish the electrochemical sensor by leaching out the lead(II) from the imprinted polymer particles, and a carbon paste electrode was modified with lead(II) IIPs. There is a distinct difference in the response between the electrodes modified with IIPs and the electrodes modified with NIPs, which included the open circuit sorption of Pb²⁺ on the electrode and its reduction to its metallic form. The influence factors on the response behavior of the electrodes were investigated and optimized. The results show the introduced sensor was linear from 1.0 × 10⁻⁹ to 7.5 × 10⁻⁷ mol L⁻¹, and the limit of detection (LOD) was 1.3 × 10⁻¹¹ mol L⁻¹ (S/N = 3). Finally, the sensor was successfully applied to the trace determination of lead ions in various real samples.