Publications scientifiques
Sarrah Sonita Poungoue Hanga
Arlette Danelle Djitieu Deutchoua
Autres affiliations : University of Douala
Morel Brinda Medonjeu Ntanhaning
Gustave Kenne Dedzo* (Auteur correspondant)
Electroanalysis
Considering the importance of antioxidants in food and medical industries, the accurate evaluation of their reactivity is of capital importance. In this work, a new electrochemical approach based on the cupric reducing antioxidant capacity (CUPRAC) is proposed for the accurate evaluation of antioxidant properties. The electrochemical behavior of the complex ([Cu(Nc) 2 ] 2+ ) obtained from the reaction between copper(II) and neocuproine (Nc) used in the CUPRAC method was studied to identify the ideal Cu/Nc molar ratio. The Cu/Nc ratio of 4/3, usually used in the CUPRAC method, was not suitable because of the partial reaction of Nc with Cu(II). A more appropriate Cu/Nc molar ratio of 1/7 was experimentally determined by voltammetry at a stationary or rotating electrode. With this molar ratio, [Cu(Nc) 2 ] 2+ presents a fast and monoelectronic system controlled by diffusion. This allowed antioxidant properties determination by chronoamperometry, by following the [Cu(Nc) 2 ] 2+ reduction current as a function of the tested antioxidant. Ascorbic acid and Trolox used in this study as model antioxidants showed inhibition concentrations values (IC 50 ) very close to the expected theoretical values. These results are proof that the developed electrochemical method is accurate and allows a fast and efficient evaluation of antioxidant properties while minimizing interferences encountered using spectrophotometric methods.
