The synthesis of silver microparticles with surface film of silver sulfide mixed with graphite powder has yielded an electrochemical sensor capable of detecting cyanide with good sensitivity. silver and silver sulfide microparticles was characterized by cyclic voltammetry (CV), X-ray diffraction (XRD), X-ray Fluorescence (XRF), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometry X-ray (EDX). Potentiometric assays were performed to determine the selectivity coefficient of the sensor