Centrifugal Partition Chromatography. V. Octanol-Water Partition Coefficients, Direct and Indirect Determination

Abstract

Octanol-water partition coefficients (K_oct) are one of the accepted physico-chemical parameters for predicting the biological effects of organic chemicals. It is demonstrated that centrifugal partition chromatography (CPC) can be used to determine directly the K_oct values from about 0.003 to 300. The mobile phase must be water and the stationary phase must be octanol for accurate determination of the larger K_oct values. To reduce retention times and volumes, the stationary phase volume can be decreased. This can be done using an original mode: the “underload” mode. The “underloading” procedure is described. To extend the K_oct range which can be determine by CPC, the system hexane (60%) octanol (40%)-water was used. A single linear relationship between log K in this system and log K_oct was established allowing to determine the K_oct values up to 1000 (log K_oct=3).