Application of nanosized gold and graphene modified carbon ionic liquid electrode for the sensitive electrochemical determination of folic acid

Abstract In this study a new electrochemical folic acid (FA) sensor was proposed by using gold nanoparticles (AuNPs) and graphene (GR) modified carbon ionic liquid electrode (CILE) as the working electrode. GR and AuNPs were directly electroreduced on the surface of CILE to get the modified electrode, which exhibited excellent electrochemical performances due to the specific characteristics including higher conductivity and larger surface area. The modified electrode showed excellent electrocatalytic ability to the oxidation of FA with an irreversible oxidation peak appeared at + 1.05 V (vs. SCE) in pH 5.5 phosphate buffer solution. Electrochemical behaviors of FA on the modified electrode were carefully investigated with the electrochemical parameters calculated. Under the optimal conditions and by using differential pulse voltammetry, the oxidation peak currents were linear to FA concentration in the range from 0.01 μmol L − 1 to 50.0 μmol L − 1 with the detection limit as 2.7 nmol L − 1 (3σ). The proposed method was successfully applied to the FA tablet sample determination with satisfactory results.