: The electrochemical behavior of a Nafion-1,10-phenanthroline-modified carbon paste electrode (CMCPE:
Chemically Modified Carbon Paste Electrode) immersed in a supporting electrolyte 0.1 mol.L-1 acetate buffer solution
(pH 4.5) containing iron(II) metal ion has been studied, using cyclic voltammetry, differential-pulse voltammetry and
impedance spectroscopy. Optimal analytical parameters (preconcentration potential and time, pH, electrode rotation) for
iron(II) metal ion determination have been established and correlated with the surface morphology of the CMCPE
surface, the chemical composition analysis of the surface and the impedance measurements of the CMCPE immersed in
the supporting electrolyte. Assuming a simple approach based on a redox polymer-modified electrode, the experimental
impedance values were fitted to an equivalent circuit model. It was shown that among various potentials used for
iron(II) accumulation in the Nafion-film, the potential of +1.3 V vs. Ag/AgCl/3 mol. L-1 KCl allowed a better
differential-pulse determination of the examined iron(II) metal ion in the supporting electrolyte. The work was
expanded to real applications with the determination of iron(II) metal ion in groundwater samples collected in a village
located at the outskirts of Ouagadougou, the Capital of Burkina Faso.

Keywords: Iron(II) metal ion; Nafion-1,10-phenanthroline-modified carbon paste electrode; Differential-pulse
voltammetry; Impedance measurements.

Iron(II) metal ion; Nafion-1