Urinary excretion of the metabolites of n-hexane and its isomers during occupational exposure

Environmental exposure to commercial hexane (n-hexane, 2-methylpentane, and 3-methylpentane) was tested in several work places in five shoe factories by taking three grap-air samples during the afternoon shift. Individual exposure ranges were 32-500 mg/m3 for n-hexane, 11-250 mg/m3 for 2-methylpentane, and 10-204 mg/m3 for 3-methylpentane. The metabolites of commercial hexane in the urine of 41 workers were measured at the end of the work shift. 2-Hexanol, 2,5-hexanedione, 2,5-dimethylfuran, and gamma-valerolactone were found as n-hexane metabolites and 2-methyl-2-pentanol and 3-methyl-2-pentanol as 2-methylpentane and 3-methylpentane metabolites. The presence of metabolites in the urine was correlated with occupational exposure to solvents. n-Hexane exposure was correlated more positively with 2-hexanol and 2,5-hexanedione than with 2,5-dimethylfuran and gamma-valerolactone. A good correlation was also found between total n-hexane metabolites and n-hexane exposure. 2-Methyl-2-pentanol and 3-methyl-2-pentanol were highly correlated with 2-methylpentane and 3-methylpentane exposure. The results suggest that the urinary excretion of hexane metabolites may be used for monitoring occupational exposure to n-hexane and its isomers.