Electrochemical determination of mangiferin using glassy carbon electrodes modified with carbonaceous nanomaterials

The mangiferin molecule (MG) is a c-glucosyl xanthone present in the mango tree. Its structure contains polyphenolic groups which are responsible for its antioxidant properties. These properties make this natural molecule, an attractive additive for pharmaceutic products and functional food. In this work, we report on an investigation of the electrochemical behavior of mangiferin upon bare and carbonaceous nanomaterials-modified glassy carbon electrodes (GCEs). The electrodes modification was made with graphene oxide (GO), multi-walled carbon nanotubes (MWCNT) or single-walled carbon nanotubes (SWCNT) suspended in water or in Nafion® ion exchanger. The data obtained show that the mangiferin's oxidation process is governed by a mixed mechanism of diffusion and adsorption. By implementing the electrodes modification, it was determined that, not only the sensitivity increases in the oxidation signal of MG, but also the adsorption of the oxidized product is lower, allowing the execution of several successive measurements without the need to polish the electrode. Calibration curves were performed for all three systems (GCE-GO, GCE-MWCNT, and GCE-SWCNT); the obtained correlation coefficients were higher than 0.9940 with detection limits of 0.063 μM, 0.189 μM, and 0.476 μM respectively. These results make the developed material a viable option for direct determination of mangiferin.