Electrochemically Activated Screen-Printed Graphene Electrochemical Sensor for Daidzein Determination in Edible Peanut Oils

In this work, we designed a novel and simple electrochemical approach for the determination of daidzein antioxidant (Dz) in peanut oil samples. The Dz determination was based on anodic stripping linear voltammetry using screen-printed graphene electrodes (SPGEs) activated in acidic media, where a strong adsorption of Dz on activated graphene was obtained. In this regard, electroanalytical parameters such as the scan rate, supporting electrolyte, pH, and accumulation step were optimized to ensure the best conditions for the selective and sensitive Dz quantification. The electrochemical method developed for the determination of Dz exhibits a linear behavior of the anodic peak current in the concentration range from 0.05 to 1 μM, with a limit of detection of 0.012 μM. The electrochemical sensor demonstrated to the capacity to quantify Dz in peanut oil samples at low concentrations without the necessity of an extensive sample pretreatment. Therefore, the electrochemical method proposed can be used as a new portable analytical tool for the in situ quality control of peanut oil samples.