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The liquid/air partition coefficients of four common terpenes, a-pinene, ,B-pinene, 3-carene, and limonene, have been determined in vitro using head space technique. The liquids used were water, human blood, and olive oil. a-Pinene, P-pinene, and 3-carene were practically insoluble in water The aim of the present study was to determine the in vitro blood/air, oil/air, and water/air partition coefficients of four common terpenes: a-pinene, ,Bpinene, 3-carene, and limonene. Materials and methods CHEMICALSThe chemicals used were sodium chloride (analytical grade, Merck), olive oil (purum, Kebo Lab AB), apinene (98%, Aldrich), a-pinene (98%, Aldrich), 3-carene (95%, Aldrich), and limonene (99%, Fluka Chemie AG). All chemicals were used without further purification. SAMPLE PREPARATIONBlood was collected from the brachial vein of ten healthy volunteers (five men and five women) in heparinised 10 ml Vacutainer tubes (Beckton Dickinson, Paramus, NJ) and were pooled immediately before the experiment. Aliquots of 0 5 ml olive oil, 2 ml water (containing 0 3 M sodium chloride), or 2 ml pooled fresh human blood were added to a head space vial (22-4 ml, SD = 0 2). A reference vial was filled with glass beads to a volume corresponding to the sample volume (0-5 and 2 ml, respectively) and treated exactly the same way as the sample; this was done to reduce the difference in pressure which could affect the partition coefficient.To obtain the desired concentrations (0-84-354 uM in oil and 0-21-89 jM in blood and water) 3, 30, or 250 pl of each terpene was added to a thermostated (37°C) air chamber of 4-445 1 volume. After 20 minutes equilibration (37C) a sample of0 1, 0-25, or 0-5 ml was taken out with a gas tight syringe and added into a head space vial. Before the standards were made, the head space vials were thermostated (37C) and capped with Teflon lined rubber stoppers. An air volume (corresponding to the sampling volume later added to each vial) was taken from each vial with a gas tight syringe. Blanks ofblood, olive oil, and water were made without added terpenes. Double samples were made, in each liquid, for all the concentrations. GAS CHROMATOGRAPHIC ANALYSISThe terpenes in the gas phase of the headspace vials were determined by gas chromatography (Perkin Elmer 8700) using a head space autosampler (Perkin Elmer HS-101) and a flame ionisation detection. A polar, wide bore capillary glass column (Supelcowax 10, Supelco inc 30 m, 0 75 mm inner diameter,

The renal elimination of verbenols after experimental exposure to (+) and (-)alpha-pinene was studied in humans following exposure to 10, 225, and 450 mg.m-3 terpene in an exposure chamber. The pulmonary uptake was about 60%. About 8% was eliminated unchanged in exhaled air. Depending on the exposure level, about 1%-4% of the total uptake was eliminated as cis- and trans-verbenol. Most of the verbenols were eliminated within 20 h after a 2-h exposure. The renal excretion of unchanged alpha-pinene was less than 0.001%.

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