Electrocatalytic effect of nano-wrinkled layer carbonaceous electrode: determination of folic acid by differential pulse voltammetry

Nano-wrinkled layer carbonaceous electrode materials were prepared from pyrolytic carbonization of different proportions of mixtures coal tar pitch (CTP) and polystyrene (PS) composite. The PS content in carbonaceous materials was in between 10% and 70% PS. The electrodes were characterized using scanning electron microscopy (SEM) and electrochemical methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CTP-PS4 (50% PS content) electrode was more reductant than the other electrodes. Similarly, electrocatalytic activity of CTP-PS4 for folic acid (FA) was higher than the other electrodes. The electrode was used in the determination of FA by differential pulse voltammetry (DPV). Under optimal conditions, the anodic current of FA was linear in the concentration range from 0.25 to 40 mu mol/L. The obtained linear range calibration plot of the concentration of FA vs. peak current resulted in two linear slope values. The first equation for FA was Ip(FA)=0.2476+3.9005 [FA] (R-2: 0.9970) with the linear range from 0.25 to 1.5mol/L (LOD: 0.011mol/L; S/N=3). The second linear equation was Ip(FA)=4.5377+1.2509 [FA] (R-2: 0,9957) with the linear range from 3.0 to 40mol/L (LOD=0.092mol/L; S/N=3). The proposed method was applied for the determination of FA in human serum with recovery rate from 97.3 to 101.3%.