Direct Measurement of Octanol-water Partition Coefficients Using Centrifugal Partition Chromatography with a Back-flushing Technique

Octanol-water partitioning coefficients (K(oct)) are an accepted parameter in the prediction of biological activity of organic chemicals. Centrifugal Partition Chromatography (CPC), a form of counter current chromatography, is shown to have several distinct advantages in the direct measurement of these partition coefficients. A new CPC technique, back-flushing, is introduced which allows the direct determination of K(oct) values that previously were thought to be unobtainable by this method. The theoretical and experimental aspects of this technique are presented. K(oct) of six solutes that ranged from 75 to 3091 were determined and compared with literature values. The direct determination of K(oct) values greater than 104 may be possible. Both accuracy and ease of automation may make this a highly desirable method by which to measure octanol-water partition coefficients in the future