An HPLC assay of hydroxyl radicals by the hydroxylation reaction of terephthalic acid

Abstract An HPLC assay for hydroxyl radicals is described. The hydroxyl radical was trapped by terephthalic acid (non‐fluorescent), and 2‐hydroxyl terephthalic acid (fluorescent) was quantitated by HPLC‐fluorescence detection. At a terephthalic acid concentration of 4.25 mmol/L, the hydroxyl radical formed in the Fenton reaction was successfully assayed in the concentration range of hydrogen peroxide of 2.5–50 µmol/L, where the concentration of Fe(II) was 50 µmol/L. The fluorescence of 2‐hydroxy terephthalate was stable at 24 h, and its detection limit by this method was 5 nmol/L (100 fmol). Copyright © 2004 John Wiley & Sons, Ltd.