Determination of liquid/air partition coefficients for dilute solutions of ethanol in water, whole blood, and plasma.

Liquid/air partition coefficients were determined for dilute solutions of ethanol in water, whole blood, and plasma at various equilibrium temperatures from 20 degrees to 40 degrees C. Ethanol was determined in air and liquid samples by gas chromatography. The partition coefficients decreased exponentially as the temperature of equilibrium increased. The slopes of the regression lines were not significantly different and the mean temperature coefficient of solubility was 6.5% 1 degrees C. At 37 degrees C, the partition coefficients for water/air, whole blood/air, and plasma/air were 2133, 1756, and 2022, respectively. The blood/air relationships were well correlated with the water content of the samples (r = 0.67, p less than 0.001). With sodium fluoride as the blood anticoagulant at 2.0, 5.0, and 10.0 mg/mL, the concentration of ethanol in the equilibrated air phase rose by 3.2%, 5.4%, and 8.9%, respectively compared with heparinized blood.