A new strategy for preparing modified carbon nanotubes paste electrode was suggested. A selective ionophore was chemically grafted onto SiO 2 /Fe 3 O 4 nanoparticles, as a modified core/shell structure, for the potentiometric detection of Pb2+ ion. The surface morphology and electrical properties of the prepared electrode were characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The results indicated a remarkable increase in the performance in terms of Nernstian slope, selectivity, detection limit, dynamic concentration range and lifetime with high stability in the potential responses for Pb2+ ion, in comparison with the other conventional electrodes. The presence of Schiff base/SiO 2 /Fe 3 O 4 in multi-walled carbon nanotubes/ionic liquid matrices of sensor leads to exhibit linear ranges of 2.50 × 10−9 –1.00 × 10−1 mol L−1 with a detection limit of 10−9.02 mol L−1 for Pb2+. The suggested sensor was successfully applied to the highly sensitive determination of trace amounts of Pb2+ in various water, petrochemical waste water and biological samples with satisfactory results.
