Iodide-induced adsorption of lead(II) ion on a glassy carbon electrode modified with ferroferric oxide nanoparticles

Spherical Fe3O4 nanoparticles (NPs) were prepared by hydrothermal synthesis and characterized by scanning electron microscopy and X-ray diffraction. A glassy carbon electrode was modified with such NPs to result in a sensor for Pb(II) that is based on the strong inducing adsorption ability of iodide. The electrode gives a pair of well-defined redox peaks for Pb(II) in pH 5. 0 buffer containing 10 mM concentrations of potassium iodide, with anodic and cathodic peak potentials at -487 mV and -622 mV (vs. Ag/AgCl), respectively. The amperometric response to Pb(II) is linear in the range from 0. 10 to 44 nM, and the detection limit is 40 pM at an SNR of 3. The sensor exhibits high selectivity and reproducibility. (author)