The antioxidant activity of teas measured by the FRAP method adapted to the FIA system: optimising the conditions using the response surface methodology
| Autor: | Vitor C. Almeida, Jesuí Vergílio Visentainer, Lais Bukman, Alessandro C. Martins, Alexandro M.M. Vargas, Érica Oliveira Barizão, Juliana C.G. Moraes |
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| Rok vydání: | 2011 |
| Předmět: |
Flow injection analysis
Chromatography Antioxidant Ferric Compounds Tea Chemistry medicine.medical_treatment Analytical chemistry Oxidation reduction General Medicine Antioxidants Chemistry Techniques Analytical Analytical Chemistry Volumetric flow rate Volume (thermodynamics) Reagent Flow Injection Analysis medicine Response surface methodology Oxidation-Reduction Food Science |
| Zdroj: | Food chemistry. 138(1) |
| ISSN: | 1873-7072 |
| Popis: | This study proposes a FRAP assay adapted to FIA system with a merging zones configuration. The FIA system conditions were optimised with the response surface methodology using the central composite rotatable design. The optimisation parameters studied were: the carrier flow rate, the lengths of the sample and reagent loops, and reactor length. The conditions selected in accordance with the results were: carrier flow rate of 1.00 ml/min, length of the loops 18.2 cm and length of the reaction coil 210.1 cm. The detection and quantification limits were, respectively, 28.6 and 86.8 μmol/l Fe(2+), and the precision was 1.27%. The proposed method had an analytical frequency of 30 samples/h and about 95% less volume of FRAP reagent was consumed. The FRAP assay adapted to the FIA system under the optimised conditions was utilised to determine the antioxidant activity of tea samples. |
| Databáze: | OpenAIRE |
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