High electrocatalytic oxidation of folic acid at carbon paste electrode bulk modified with iron nanoparticle-decorated multiwalled carbon nanotubes and its application in food and pharmaceutical analysis

A simple and rapid method was employed for the modification of carbon paste electrode with iron nanoparticle-decorated multiwalled carbon nanotubes (MCPE/Fe-MWCNTs). The synergistic effect of iron nanoparticle and multiwalled carbon nanotubes results in the electrocatalytic oxidation of folic acid (FA). MCPE/Fe-MWCNTs were characterized by FESEM by recording surface morphological images; the elemental analysis of the electrode was carried out by EDX and electrochemical impedance spectroscopy to investigate surface-interface properties between solid electrode surface and the solution. The electronic transitions during the electrochemical oxidation of FA were investigated using spectroelectrochemical data. Cyclic voltammetry and differential pulse voltammetric techniques were used for the qualitative and quantitative analysis of FA respectively at physiological pH. MCPE/Fe-MWCNTs produced a linear response to FA over a wide concentration range with a detection limit of 2.4 ± 0.9 nM (S/N = 3). The fabricated sensor was successfully utilized as an effective tool for the determination of FA in food samples, human blood serum, and pharmaceuticals.