Electrochemical evaluation of total antioxidant capacity of beverages using a purine-biosensor

► Adenine and guanine were immobilized on glassy carbon electrode to develop a biosensor. ► Hydroxyl radical was used to promote oxidative damage on the purine-based biosensor. ► Antioxidants protect DNA bases from the damage. ► Antioxidant used were ascorbic acid, resveratrol, gallic, caffeic and coumaric acid. ► Biosensor was used for the evaluation of the antioxidant capacity of beverages.