Rapid, fully automated flow injection antioxidant capacity assay

Area of Science:

• Analytical Chemistry
• Biochemistry

Background:

• Assessing antioxidant capacity is crucial for understanding the health benefits of various substances.
• Existing methods can be costly or time-consuming.
• A need exists for rapid, affordable, and reliable antioxidant capacity assessment techniques.

Purpose of the Study:

• To develop and validate a low-cost, laboratory-made flow injection analysis (FIA) system for antioxidant capacity determination.
• To evaluate the performance of the developed FIA method in terms of speed, precision, and detection limits.
• To assess the applicability of the method to real-world samples like wines and honeys.

Main Methods:

• A flow injection method was designed using a laboratory-made analyzer.
• A small sample volume (30 microL) was injected into an acetate buffer stream (pH 4.6) merging with ABTS radical cation (ABTS*(+)) reagent.
• Absorbance was measured at 414 nm to quantify antioxidant capacity.

Main Results:

• The method achieved a high sample throughput of up to 120 samples per hour.
• A detection limit of 1.3 microM trolox was obtained, with precision better than 5% relative standard deviation.
• The linear range was 4-100 microM trolox, expandable to 250 microM using concentration gradients.
• The method showed good correlation with phenolic content in wine (r=0.94-0.96) and honey (r=0.89).

Conclusions:

• The developed low-cost FIA method provides a rapid, precise, and sensitive approach for antioxidant capacity assessment.
• The system is suitable for analyzing pure compounds and complex matrices such as wines and honeys.
• The method offers valuable insights into reaction kinetics from a single injection, enhancing its utility.