HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF URINARY 2,5-HEXANEDIONE AS MONO-2,4-DINITROPHENYLHYDRAZONE USING ULTRAVIOLET DETECTION

The good correlation between exposure to n-hexane and 2,5-hexanedione urinary excretion confers on this diketone an important toxicological meaning. This paper proposes a reversed-phase HPLC method which includ es, after acid hydrolysis, a derivatization step of 2,5-hexanedione wi th 2,4-dinitrophenylhydrazine at 70 degrees C for 20 min. The reaction conditions, such as temperature, reagent concentration and time, are optimized so as to allow the condensation of a single carbonyl group. A linear response mas obtained in the 0.19-20.0 mg/l range with a dete ction limit of 0.03 mg/l, corresponding to a signal-to-noise ratio of 3. A phosphate buffer (pH 3.3)-acetonitrile mixture (50:50) as the elu ent and UV detection at 334 nm were used.