A comparative study of the molecular lipophilicity indices of vitamins A and E, and of some precursors of vitamin A, estimated by HPLC and by different computation methods

Abstract

Lipophilicity indices for vitamins A and E, and for some precursors of vitamin A, have been determined for the first time by reversed-phase high-performance liquid chromatography (RPHPLC) on C 18 and C 8 columns. For each column the mobile phases were methanol-water mixtures with methanol in volume proportions from 86 to 90% ( υ/υ ) in 1% steps. The regression correlation coefficients obtained for both stationary phases were excellent (usually >0.999). To compare the experimental lipophilicity estimated for the compounds by use of log k′ w, S , φ 0, the means of k′ and log k′ , and the scores of k′ and log k′ corresponding to the first principal component, and log P values calculated by use of different computer software a correlation matrix was constructed. Better correlations were obtained in both cases between the mean of k′ and the mean of log k′ , and scores corresponding to the first principal component obtained by applying principal-components analysis to the matrix of retention factors and computed log P values. The best correlations were found between the mean of k′ and scores corresponding to the first principal component determined on C 8 and most of the computed log P values. © 2009 Akademiai Kiado.