Identification of phenol oxidation products

When phenol is treated with sodium hydroxide and oxygen (in the form of air), the salts of organic acids are formed. These acids cannot be analysed by gas chromatography, since the acids are unstable and decompose. Liquid chromatography is a practicable alternative for analysis. Paired ion chromatography has been found to be the best method for the analysis of this mixture of acids, using reversed phase partition chromatography. The acids identified were oxalic, acetic, propionic, croconic, and rhodizonic acid.