Rapid sensing of antioxidant capacity based on electrochemiluminescence induced by electrochemically generated reactive oxygen species

A simple and rapid electrochemiluminescence (ECL) method for the measurement of antioxidant capacity using a portable ECL device with a screen-printed electrode is described. The ECL method is based on the luminous reaction of reactive oxygen species (ROS), luminol radicals and antioxidants. ROS are generated by the electrochemical reduction of dissolved oxygen and competitively react with the luminol and antioxidants. The ECL intensity depends on the antioxidant capacity because the radicals are neutralized by the antioxidants, suppressing the luminous reaction. An antioxidant standard curve was generated using different concentrations of known amounts of Trolox by ECL measurement and the detection limit for antioxidant capacity was found to be 0.06 mM of Trolox. An antioxidant capacity of beverages (22 types) was evaluated by comparing with the standard curve of Trolox. The time necessary for the ECL measurement of antioxidant capacity is only two minutes after combining the sample solution with luminol on a screen-printed electrode.