Introduction

Lipophilicity is a molecular parameter widely used in estimation of biological and environmental behavior of many substances (1-3). There are several experimental methods for its approximation, such as shake-flask method with water-octanol partition system, potentiometric titration, etc. or computational approaches. One of the experimental approaches for lipophilicity determination is chromatography, usually on reversed phases (RP) (4). There are many studies which deal with the chromatographic determination of lipophilicity, mostly by high performance liquid chromatography (HPLC) and thin layer chromatography (TLC) (5-7). The chromatographic lipophilicity is usually expressed as the RM0 parameter (TLC) or logk0 (HPLC). These parameters refer to the retention of a compound in pure water (0% of the modifier in the mobile phase). However, the chromatographic lipophilicity (RM or logk) can be determined in different stable chromatographic conditions with mobile phases which are a combination of certain volume fractions of water and a modifier (usually methanol or acetonitrile).