DETERMINATION OF ALPHA-NAPHTHOL IN HUMAN URINE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A high performance liquid chromatography/fluorescence (HPLC) method for quantitative analysis of alpha-naphthol in urine was developed. The method validation analysis showed the method to be in analytical control meaning that no significant systematical errors could be demonstrated. The entire run time of chromatography was 10 min using isocratic elution (acetonitrile:water (35:65)), and the retention time for a-naphthol was 5.9 min. The short run time in combination with the low limit of detection (0.038-mu-mol/l) make the method potentially applicable for surveillance of naphthalene exposure in the working environment. The developed method is presently used for measurement of (alpha-naphthol in urine samples from workers employed who are characterized by a low airborne exposure level of polycyclic aromatic hydrocarbons in general is low, i.e. less than 25-mu-g/m3. The preliminary results of 123 workers showed a range of alpha-naphthol in urine from the limit of detection (LD) up to 1.7-mu-mol/l, whereas non-exposed control individuals (n = 113) showed a range from LD up to 0.7-mu-mol/l.