Analytical Sciences

Abstract − Analytical Sciences, 32(2), 135 (2016).

Low-interferences Determination of the Antioxidant Capacity in Fruits Juices Based on Xanthine Oxidase and Mediated Amperometric Measurements in the Reduction Mode
Madalina-Petruta BUCUR, Maria-Cristina RADULESCU, Bogdan BUCUR, and Gabriel Lucian RADU
Centre of Bioanalysis, National Institute of Research and Development for Biological Sciences, 296, Splaiul Independentei, Bucharest 060031, Romania
A low-interferences enzymatic sensor for evaluating the antioxidant capacity was developed. Xanthine oxidase was used to produce superoxide radicals that spontaneously dismutate to hydrogen peroxide. Low xanthine concentrations were used to minimize the rapid dismutation of the superoxide radical before its fast reaction with antioxidants. The sensor operates in the reduction mode, and evaluations with low interferences of the antioxidant capacity are based on the detection of remaining hydrogen peroxide using Prussian blue electrodes at low potentials. The linear calibration graph is between 2 – 10 μM ascorbic acid. No interferences were observed from easily oxidisable substances including uric acid, which is produced in the enzymatic reaction or other substances usually found in foods. The method was used to evaluate the antioxidant capacity in different real juice samples.