Adsorption and Voltammetric Determination of Gallic Acid at the Surface of Alginate/Aminated Carbon Nanoparticles bilayer in Some Herbs

In this study, layer-by-layer deposition method by sodium alginate polymer and carbon nanoparticles were used for modification of glassy carbon electrode surface. The modified electrode surface was studied by using scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The SEM images has been utilized to estimate the size of carbon nanoparticles on electrode surface which is approximately 47-57 nm. Gallic acid and ascorbic acid the antioxidant compounds naturally present in foods were determined with modified glassy carbon electrode using differential pulse voltammetry technique. The effect of. scan rate and pH parameters were optimized. In optimal conditions, using differential pulse voltammetry, the linear range for the concentration of gallic acid and ascorbic acid are 0.1-100.0 and 1.0-1000.0 µM and the limit of detection equal to 0.057 and 0.368 µM is estimated respectively. Finally, Gallic acid was determined in some herbs such as marjoram, thyme and mallow.