Determination of methyl-substituted phenols in water by gas chromatography with preliminary iodination

A procedure is developed for determining phenol; 2-, 3-, and 4-methylphenols, and 2,4- and 2,6-dimethylphenols in aqueous media, which consists in the synthesis of iodine derivatives, their extraction with toluene, and determination by gas chromatography with electron-capture detection. The optimal conditions for the iodination of phenols in water are found; also the extraction and gas chromatography behavior of methylphenols and their iododerivatives are investigated. To make the identification of iododerivatives of methylphenols more reliable, they are subjected to acylation with acetic anhydride in the extract. The analytical range of phenols in water is 0.01–10 μg/L, the relative standard deviation is 2–6%, and the duration of analysis is up to 40 min.