Identification of cis- and trans-verbenol in human urine after occupational exposure to terpenes.

Urine from sawmill workers exposed to alpha-pinene, beta-pinene and delta-3-carene was collected and hydrolyzed with beta-glucuronidase at pH 5.0 for 24 h at 37 degrees C. After hydrolysis the urine was cleaned on a SEP-PAK C18 cartridge. The cartridge was eluted with n-heptane. The eluate was injected onto a gas chromatograph equipped with a 25-m (0.32-mm ID) SP-1000 capillary column. The major peak in the chromatogram was identified by GC-MS as trans-verbenol by electron impact at 70 eV. cis-Verbenol was also identified. These metabolites could not be detected in non-hydrolyzed urine from the exposed workers or in hydrolyzed urine from an unexposed individual. The recoveries of the verbenols from hydrolyzed urine were in the range of 85 to 94% and the metabolites were stable both in urine and in n-heptane after sample cleaning at -20 degrees C for at least 12 weeks. We suggest that these metabolites are formed from alpha-pinene by hydroxylation.