Chemometric Comparison of Thin-Layer Chromatography, Gradient High-Performance Liquid Chromatography, and Computational Methods for Lipophilicity Assessment of Model Compounds

Summary

Thin-layer chromatography (TLC) on two adsorbents (RP18 and CN) and with six modifiers (acetonitrile, acetone, dioxane, propan 2-ol, methanol, and tetrahydrofurane), followed by classical R_M value extrapolation (previous results), was chemometrically compared with new one-run gradient high-performance liquid chromatography (HPLC) (C18, C18e, CN, and DIOL columns, acetonitrile, and methanol as modifiers) and, additionally, with seven computational algorithms (ALOGPs, AClogP, ALOGP, MLOGP, KOWWIN, XLOGP2, and XLOGP3) as a lipophilicity assessment tool on 35 model compounds with known lipophilicity. The statistical significance of intercepts and slopes of Collander equation (log P — retention dependence) and their values were compared. Whole results data set was subjected to scaled principal component analysis, which allowed exploring two main trends in these data. It can be concluded that one-run gradient HPLC does not outperform TLC in lipophilicity determination. Very good correlations were obtained between real log P and computational approaches; however, this is not a surprise for such simple molecules.