Folin–Ciocalteu reagent

The Folin- Ciocalteu reagent (FCR), is a mixture of molybdophosphoric acid and tungstophosphoric acid. It is used for the colorimetric determination of phenolic and polyphenolic antioxidants. However, with this reagent can be not the total phenols specific measure because it also reacts with other reducing substances. Therefore, the total antioxidant capacity of the sample is determined, not only the proportion of phenolic components.

It is named after its developers Otto Folin and Ciocalteu Vintila, which it presented in an article for the determination of tyrosine and tryptophan in proteins 1927.

An article from 1951 entitled Protein measurement with the Folin phenol reagent was 187 652 with citations of the most cited articles in the period 1945-1988.