I performed the total flavonoid content assay using sodium nitrite, aluminum chloride, and sodium hydroxide solutions. However, my extract has a strong inherent color (dark yellow and dark red), and I'm wondering whether I need to apply a blank correction.

To account for the background color, I prepared a blank by using the sample with all reagents except the aluminum chloride solution. However, the results appear unusual—my calculated flavonoid values are significantly higher than those obtained from the Folin–Ciocalteu assay for total phenolic content, which doesn't seem consistent or reasonable.

Please advise the correct approach for the blank correction and the appropriate way to perform this assay for my samples.

Thank you very much for your help.

Best regards,