An Electrochemical Method for Sensitive Determination of Antioxidant Capacity

A simple and sensitive electrochemical method for the determination of antioxidant capacity has been Studied. 4-hydroxybenzoic acid (4-HBA) was used as a trapping agent for photogenerated (OH)-O-center dot radicals, leading to 3,4-dihydroxybenzoic acid (3,4-DHBA). Square-wave voltammetry was used to quantify the amount of 3,4-DHBA formed from the reaction between 4-HBA and (OH)-O-center dot. Addition of antioxidants induced the competition between 4-HBA and antioxidants toward (OH)-O-center dot elimination, resulting in a decrease of the measured current. The IC50 for different standard antioxidants was calculated and expressed in Trolox equivalent antioxidant capacity (TEAC). The proposed method was successfully compared to a fluorimetric one.