Simultaneous determination of hydroquinone, catechol and phenol in urine using high-performance liquid chromatography...

A method was developed for simultaneous determination of urinary hydroquinone, catechol and phenol using high-performance liquid chromatography (HPLC) with variable-wavelength fluorimetric detection. Urine samples, after acid hydrolysis, were saturated with sodium sulphate and extracted by diethyl ether. The two buffers used for gradient elution were (A) 10 mM sodium acetate containing 0.5% (v/v) acetic acid and (B) the same as buffer A but containing an additional 20% (v/v) acetonitrile. Hydroquinone, catechol and phenol were separated in a C18 column and detected at 2.9, 6.8 and 13.6 min, respectively. The recovery and reproducibility were generally over 90%. Over 300 extracted samples were analysed and no change in column efficiency was noted. Comparisons were also made with HPLC using ultraviolet (UV) detection and with gas chromatography (GC). The proposed method appears to be more sensitive and reliable than other existing methods. This new method was also validated with urine samples collected from cigarette smokers and from refinery workers exposed to low concentrations of benzene.