Batch-injection analysis with amperometric detection of the DPPH radical for evaluation of antioxidant capacity. (1st February 2016)

• Record Type: Journal Article
• Authors: Oliveira, Gracy K.F.; Tormin, Thiago F.; Sousa, Raquel M.F.; de Oliveira, Alberto; de Morais, Sérgio A.L.; Richter, Eduardo M.; Munoz, Rodrigo A.A.
• Is Part Of: Food chemistry. Volume 192(2016)
• Page Start: 691
• Page End: 697
• Publication Date: 2016-02-01
• Subjects: Amperometry -- Antioxidant -- BIA -- DPPH -- Plant extracts; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2015.07.064
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Batch-injection analysis (BIA) with amperometric detection of DPPH consumption. Antioxidant capacity measurement (EC50 value) based on DPPH consumption. BIA and spectrophotometry methods agree statistically for antioxidants. BIA method provided comparable EC50 measurements to plant and tea samples. Abstract: This work proposes the application of batch-injection analysis with amperometric detection to determine the antioxidant capacity of real samples based on the measurement of DPPH radical consumption. The efficient concentration or EC50 value corresponds to the concentration of sample or standard required to scavenge 50% DPPH radicals. For the accurate determination of EC50, samples were incubated with DPPH radical for 1 h because many polyphenolic compounds typically found in plants and responsible for the antioxidant activity exhibit slow kinetics. The BIA system with amperometric detection using a glassy-carbon electrode presented high precision (RSD = 0.7%, n = 12), low detection limit (1 μmol L −1 ) and selective detection of DPPH (free of interferences from antioxidants). These contributed to low detection limits for the antioxidant (0.015 and 0.19 μmol L −1 for gallic acid and butylated hydroxytoluene, respectively). Moreover, BIA methods show great promise for portable analysis because battery-powered instrumentation (electronic micropipette and potentiostats) is commercially available.