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 mu M) 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 2.88x10-6 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.