2.6.6. FRAP Assay

To determine the antioxidant activity of SeNPs, FRAP (Ferric Reducing Antioxidant Power) assay was performed. Briefly, TPTZ (2,4,6-tripyridyl-S-triazine) solution (10 mmol/L) in HCl (40 mmol/L), FeCl₃ (20 mmol/L), and acetate buffer (0.3 mol/L, pH 3.6) were used in this assay. Acetate buffer, FeCl₃, and TPTZ were mixed before use. The mixture was then heated to 37°C. Twenty μL of each sample and 180 μL of FRAP reagent were mixed in a 96-well microplate reader (37°C for 10 minutes). The absorbance of the complex was measured at 593 nm [24].