This work describes the preparation and characterization of size-controlled zinc hexacyanoferrate (III) nanoparticles (ZnH). They were prepared using different proportions of water/formamide in the complexation reaction of Zn 2+ with [Fe III (CN) 6 ] 3À. The materials were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Ultraviolet-Visible Spectroscopy (UV-vis), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Cyclic Voltammetry (CV). The cyclic voltammograms of the modified graphite paste electrode with ZnH-1, ZnH-2, ZnH-3 and ZnH-4 showed a well-defined redox couple with formal potential (E u 0) = 0.94 AE 0.01 V (n=20 mV s À1 ; KCl 1.0 M)) attributed to the redox process [Fe II (CN) 6 ]/[Fe III (CN) 6 ] in the presence of Zn 2+. The dependence of particle size on the detection of sulfite was verified.