Determination of phenols in environmental samples

Benefit description

The determination of total phenols in environmental samples such as water, soils, sediments, or pore water is carried out using the Folin-Ciocalteu reagent. This reagent consists of a mixture of molybdenum and tungsten salts that, in an alkaline medium (pH ~10), are reduced by the hydroxyl groups of the phenols, forming a blue complex (mixed oxides). The reading must be taken between 750 and 765 nm (the absorption maximum of the reduced complex). Based on the ISO 14502-1:2025 standard, Determination of substances characteristic of green and black tea — Part 1: Content of total polyphenols in tea — Colorimetric method using Folin-Ciocalteu reagent, an adaptation is made for the determination of phenols in other matrices, whether in water, sediments, or soil. Sample collection must be done in airtight containers (anoxia) and must be kept cold or frozen and in total darkness. Once in the laboratory, solid-phase extraction of the phenols will be performed prior to their spectrophotometric determination.