The use of Oscik's equation to describe the retention in reversed phase liquid chromatography.

The Oscik's equation based on the theory of conformal solutions was used to describe the chromatographic process in RP-HPLC. Theoretically calculated values of the logarithms of retention factors (logk) were compared with experimental values for a group of aromatic substances, i.e. alkylbenzenes, PAHs, and polar benzene derivatives. Studies were conducted using two columns: RP-18 and RP-4, as well as water-methanol and water-acetonitrile mixtures as mobile phases. The applicability of Everett's equation to describe the composition of surface phase was also verified. For this purpose, the excess methanol adsorption isotherm on LiChrospher RP-18e, was experimentally determined.