Oxygen electrode as a new tool to evaluate hydroxyl radical-scavenging ability

An oxygen electrode was applied to determine hydroxyl radical ((OH)-O-center dot) levels for the first time. The method is based on the determination of (OH)-O-center dot generated by the Fenton reaction using the reaction of (OH)-O-center dot with a scavenger and the resulting radical consuming an oxygen molecule stoichiometrically. Thus, the (OH)-O-center dot-scavenging abilities of antioxidant reagents, as well as the concentration of (OH)-O-center dot, can be determined by the measurement of consumption of dissolved oxygen using an oxygen electrode. A good correlation between the present method and conventional colorimetry was obtained for the estimation of the (OH)-O-center dot-scavenging activities of antioxidants. Furthermore, the results correlated with the (OH)-O-center dot-scavenging rate constants of the reagents evaluated by a "cupric ion reducing antioxidant capacity (CUPRAC)" assay. We applied the present method to estimate the (OH)-O-center dot-scavenging abilities of commercially available alcoholic drinks.