title: Batch-injection analysis with amperometric detection of the DPPH radical for evaluation of antioxidant capacity.
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 1h 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.
authors: Instituto de Química, Universidade Federal de Uberlândia, Av. João Naves de Ávila, 2121, Uberlândia, MG, Brazil.
authors: Gracy K F
authors: GK
authors: Oliveira
authors: Instituto de Química, Universidade Federal de Uberlândia, Av. João Naves de Ávila, 2121, Uberlândia, MG, Brazil.
authors: Thiago F
authors: TF
authors: Tormin
authors: Instituto de Química, Universidade Federal de Uberlândia, Av. João Naves de Ávila, 2121, Uberlândia, MG, Brazil.
authors: Raquel M F
authors: RM
authors: Sousa
authors: Instituto de Química, Universidade Federal de Uberlândia, Av. João Naves de Ávila, 2121, Uberlândia, MG, Brazil.
authors: Alberto
authors: A
authors: de Oliveira
authors: Instituto de Química, Universidade Federal de Uberlândia, Av. João Naves de Ávila, 2121, Uberlândia, MG, Brazil.
authors: Sérgio A L
authors: SA
authors: de Morais
authors: Instituto de Química, Universidade Federal de Uberlândia, Av. João Naves de Ávila, 2121, Uberlândia, MG, Brazil.
authors: Eduardo M
authors: EM
authors: Richter
authors: Instituto de Química, Universidade Federal de Uberlândia, Av. João Naves de Ávila, 2121, Uberlândia, MG, Brazil. Electronic address: raamunoz@iqufu.ufu.br.
authors: Rodrigo A A
authors: RA
authors: Munoz
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000032:analysis*; D002084:Butylated Hydroxytoluene / Q000032:analysis; D004566:Electrodes; D005609:Free Radicals / Q000032:analysis*; D005707:Gallic Acid / Q000032:analysis; D010084:Oxidation-Reduction; D010851:Picrates / Q000032:analysis*
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D005609:Free Radicals; D010851:Picrates; D002084:Butylated Hydroxytoluene; D005707:Gallic Acid; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: Amperometry; Antioxidant; BIA; DPPH(); Plant extracts