Effects of precursor salt on colloidal cobalt oxyhydroxides composition and its application in non-enzymatic glucose electrooxidation

• Published in: South African journal of chemistry 2017-01, Vol.70 (1), p.137-144
• Main Authors: Anaissi, Fauze J., Mariani, Filipe Q., Stadnik, Andreia
• Format: Article
• Language: English
• Subjects: Colloidal cobalt; Electrooxidation; Low glucose concentration; Salt inorganic
• ISSN: 0379-4350
• DOI: 10.17159/0379-4350/2017/v70a20

Colloidal cobalt oxyhydroxide [CoO(OH)] has been prepared fromprecursors cobalt acetate and cobalt nitrate. The cobalt colloids (Co.Acetate and Co.Nitrate) were characterized by simultaneous thermogravimetric/differential thermal analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy, Fourier transform infrared and electronic spectroscopy. Characterization data indicated the presence of counter ions (CH3COO– and NO3–), likely intercalated within the structure of the colloidal cobalt. The platinum working electrode chemically modified with cobalt colloid was studied by cyclic voltammetry in alkaline solution [0.5 M, NaOH], which revealed differences in the reproducibility and stability of the electroactive material. The colloidal Co.Nitrate modified electrode was applied to the non-enzymatic glucose (Glu) electrooxidation in the concentration range from 7.2 to 21.9 × 10–8 mol L–1. The limits of detection (5.87 × 10–8 mol L–1) and quantitation (1.96 × 10–7 mol L–1) calculated suggest that colloidal Co.Nitrate has the potential to be used as a sensor for low glucose concentration.