Improved FIA-ABTS method for antioxidant capacity determination in different biological samples

Area of Science:

• Biochemistry
• Analytical Chemistry
• Food Science

Background:

• Accurate measurement of total antioxidant activity (TAA) is essential for evaluating foods, beverages, and biological samples like plasma.
• Existing TAA assays often lack reproducibility with plasma due to interfering substances and masking effects.
• The ABTS method is a widely used assay for TAA but requires optimization for complex matrices.

Purpose of the Study:

• To enhance the reproducibility and reliability of total antioxidant activity (TAA) measurements, particularly in plasma.
• To investigate the impact of critical parameters like temperature and reaction time on TAA assay performance.
• To develop a rapid, repeatable method for screening TAA in diverse samples, including chemical products and beverages.

Main Methods:

• Improvement of the ABTS assay using a Flow Injection Analysis (FIA) system.
• Strict control of temperature and dispersion of sample and reagent within the FIA system.
• Evaluation of reaction time effects on TAA measurements for different substances.

Main Results:

• Temperature was identified as a critical factor influencing plasma TAA measurements, less so for simpler samples.
• Reaction time significantly impacts TAA results depending on the sample's chemical nature.
• The improved method confirmed high TAA in a methylsalicylate mouthrinse and low TAA in chlorhexidine mouthrinse, with notable TAA in white wine (Verdicchio).

Conclusions:

• The enhanced FIA-ABTS method provides a robust and repeatable assay for determining TAA in plasma and other complex biological mixtures.
• The optimized method allows for rapid screening without sample dilution and with minimal handling.
• This improved assay is valuable for accurately assessing the antioxidant capacity of various substances and biological fluids.