Synthesis, characterization and application of novel lead imprinted polymer nanoparticles as a high selective electrochemical sensor for ultra-trace determination of lead ions in complex matrixes

Abstract

We report on the design of a lead(II)-selective electrode based on the use of lead(II) imprinted polymer nanoparticles (IP-NPs), and its application for the differential pulse voltammetry determination of lead ions. The IP-NPs were obtained by precipitation polymerization of 4-vinylpyridine (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2’-azobisisobutyronitrile (the initiator), 4-(2-pyridylazo)resorcinol (the lead-binding ligand), and lead ions (the template ion) in acetonitrile solution. After polymerization, the Pb(II) in the polymer nanoparticles were leached out with dilute hydrochloric acid to create cavities for hosting Pb(II). The new sensor showed high selectivity for lead ions in the presence of common potential interferences according to the specific recognition nature of the synthesized material. A carbon paste electrode was modified with the IP-NPs, and differential pulse stripping voltammetry was applied as the detection technique after open-circuit sorption of Pb(II) ions and its reduction to the metallic form. An explicit difference in the response was observed between the electrodes modified with IP-NPs and electrodes modified with non-IP-NPs. The modified electrode responds to Pb(II) was linear in the 0.1nM to 10nM (with sensitivity of 49.179nA/nM) and in the 10nM to 10μM (with sensitivity of 30.305μA/μM) concentration range. The limit of detection (LOD) of the sensor was 30 pM (at S/N =3). The sensor was successfully applied to the trace determination of Pb(II) in spiked environmental water samples.