Differential Pulse Voltammetric Determination of Folic Acid in the Presence of Ascorbic Acid using A Glassy Carbon Electrode Modified with Reduced Graphene Oxide

Reduced graphene oxide was estimated for the modification of a glassy carbon electrode. The fabricated electrode was employed for folic acid determination in 0.1 M KCl solution (pH 14) using cyclic, linear sweep, differential pulse voltammetric and chronoamperometric techniques. The modified sensor exhibits a high electro-catalytic activity towards FA oxidation in the presence of ascorbic acid. The anodic peak current (IP) of FA increased linearly with an increase in pH (12.6–14) and scan rate (20–500 mV/s) at the ERGO/GCE. Good linearity was obtained between IP and FA concentrations (3.01–7.23 μM) with the detection (LOD) and quantification (LOQ) limits are 4.68 and 15.6 nM, respectively. Under diffusion control, the diffusion coefficient was estimated to be 2.88×10−6 cm2/s at the ERGO/GCE. The fabricated sensor gives high selectivity, good sensitivity and excellent reproducibility. Thus, the proposed method could be applied to detect FA in pharmaceutical formulations and urine samples.