Rapid, fully automated flow injection antioxidant capacity assay

J Agric Food Chem. 2005 Jun 1;53(11):4341-6. doi: 10.1021/jf050106j.

Abstract

A flow injection method for antioxidant capacity assessment based on a low-cost laboratory-made analyzer is reported. A sample of 30 microL is injected in acetate buffer stream, pH 4.6, that converges with ABTS*(+) reagent stream. Detection is achieved by monitoring absorbance at 414 nm. The proposed method achieves a sample throughput of up to 120 samples h(-1), the detection limit being 1.3 microM trolox. Precision was better than 5% relative standard deviation (n = 4) and the linear range was 4-100 microM, expanded to 250 microM trolox utilizing concentration gradients formed along the injected sample bolus. Information on reaction kinetics is obtained through a single injection. The method was applied to pure compounds and wine and honey samples. Good correlation was found between antioxidant capacity assessed through the proposed method and phenolic content: r = 0.94 for red wines, r = 0.96 for white and rose wines, and r = 0.89 for honeys.

MeSH terms

  • Antioxidants / analysis*
  • Autoanalysis / methods
  • Benzothiazoles
  • Flow Injection Analysis / methods*
  • Honey / analysis
  • Hydrogen-Ion Concentration
  • Indicators and Reagents
  • Sensitivity and Specificity
  • Sulfonic Acids
  • Wine / analysis

Substances

  • Antioxidants
  • Benzothiazoles
  • Indicators and Reagents
  • Sulfonic Acids
  • 2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid