INFLUENCES OF MOBILE PHASE METHANOL CONTENT AND SOLUTE CHARACTER ON RELATIONSHIPS BETWEEN REVERSED-PHASE LIQUID-CHROMATOGRAPHIC RETENTION AND HYDROPHOBIC-LIPOPHILIC PARAMETERS OF AROMATIC-COMPOUNDS

The usefulness of retention data determined with the liquid chromatographic system hypersil ODS:aqueous methanol for prediction of 1-octanol:water distribution coefficients and aqueous solubilities of un-ionized aromatic compounds has been studied. Predictive equations have been established which are suitable for use of either 'single-system' isocratic capacity factors or isocratic capacity factors determined at any desired mobile phase methanol content. The general applicability of both types of equations, although good, has been found to benefit from separate treatment of different types of compounds distinguished according to ionogenic properties: prediction of 1-octanol:water distribution coefficients improves upon separate treatment of data for non-ionizable and ionizable compounds, and aqueous solubilities are more reliably estimated when distinguishing between non-ionizables, acids, and bases.