Study of Cobalt Nanoparticle Modified Gold Electrode

Abstract

Phosphate detection using Cobalt nanoparticle modified gold electrode has been carried out. Cobalt oxide nanoparticles were produced by mixing a solution of cobalt chloride with 10 % glycerol and adding Ammonium hydroxide solution with stirring for 2 hours at 50  C using a magnetic stirrer. The solution was then allowed to stand for 12 hours. The precipitate obtained was filtered and calcined at 700  C for one hour. The obtained cobalt nanoparticles are mixed with nafion, then attached to a gold wire to form a modified cobalt nanoparticle electrode. The performance of this electrode was tested against a phosphate solu-tion using a three-electrode system of the Autolab Metrohm type AUT 84948. Measurements were made by immersing a modified cobalt gold electrode connected to the Metrohm Autolab three-electrode system. All phosphate measurements were carried out in KHP and KCl buffer solutions. Voltammograms of KHP did not show peaks of anodic and cathodic currents but in phosphate solution (10 ppm NaH 2 PO 4 ) showed peaks of cathodic currents at a potential of – 1.009 V. This indicated that the electrode was sensitive to phosphate ion solutions. The cathodic current increases with the phosphate concentration. The measurement detection limit is 0.47 ppm.