Miniaturized Methodologies for Determining the Total Phenol and Flavonoid Concentrations and the Antioxidant Activity

The present study describes the miniaturization of the conventional methodologies for determining the total phenol and flavonoid concentrations and the antioxidant activities using DPPH, ABTS, and ferric reducing antioxidant power (FRAP) methods. The amount of reagents used was reduced 25, 5.0, 3.6, 3.0, and 3.3 times relative to the conventional methodologies, representing a 67-96% reduction in the analysis costs. The miniaturized and conventional methodologies presented similar linearity in the same concentration range, with the determination and correlation coefficients greater than 0.99. The accuracy of the methodologies was evidenced by the relative standard deviations, which remained below 3%. The 38 samples comprising alcoholic beverages, teas, spices, jams, energy drinks, honey products, and grape derivatives analyzed using the two methodologies (miniaturized and conventional) presented similar average values. Therefore, the miniaturized methodology is proposed as an efficient, safe, and economical alternative to the conventional methods for determining the total phenol and flavonoid concentrations and the antioxidant activities using DPPH, ABTS, and FRAP methods in various matrices.

Automated summary

The study miniaturized conventional methodologies for determining total phenol and flavonoid concentrations and antioxidant activities, reducing analysis costs by 67-96%. The miniaturized methods showed similar accuracy and efficiency as the conventional ones.