Electroanalytical Behavior of Gallic and Ellagic Acid Using Graphene Modified Screen-Printed Electrodes. Method for the Determination of Total Low Oxidation Potential Phenolic Compounds Content in Cork Boiling Waters

New electroanalytical methods have been proposed for the estimation of the total content of phenolic compounds of low oxidation potential in cork boiling water, expressed as gallic acid equivalent/g dry cork, by using screen-printed electrode modified with graphene. The results obtained have been compared with spectrophotometric method (Folin-Ciocalteau) and a good correlation has been found between them. The detection limits obtained by Winefordner-Long and Clayton methods were 0.04 and 0.06 ppm for ellagic acid (EA), and 0.05 and 0.09 ppm for gallic acid (GA), respectively. The sensitivity, simplicity, selectivity, fast and low cost of the developed methodologies is also demonstrated.