Hydrophobicity estimations by reversed-phase liquid chromatography. Implications for biological partitioning processes.

Liquid chromatography has long been used for the estimation of "hydrophobicity" of solutes of biological, environmental and agricultural interest. These measurements have taken the form of octanol-water partition coefficient estimation, or less often the more fundamental processes that the octanol-water partition coefficient is intended to model. Here we review both the chromatographic methods used for these estimations, their successes and failures, and discuss pertinent solution thermodynamics of the partitioning of small molecules between bulk phases, such as octanol and water, and between a bulk phase and an interphase, such as partitioning of solute molecules into lipid layers and biological membranes.