RELATIONSHIP BETWEEN THE PHYSICOCHEMICAL PARAMETERS OF 3,5-DINITROBENZOIC ACID-ESTERS AND THEIR RETENTION BEHAVIOR ON BETA-CYCLODEXTRIN POLYMER SUPPORT

The retention of fourteen 3,5-dinitrobenzoic acid esters on thin layer s prepared from a water-insoluble beta-cyclodextrin polymer was determ ined using water-methanol mixtures as eluents. Linear correlations wer e calculated between the R(M) value of the solutes and the methanol co ncentration in the eluent, and the relationship between the chromatogr aphic characteristics (slope and intercept values of the above correla tion) and the physicochemical parameters was elucidated by stepwise re gression analysis. The R(M) value of solutes decreased or increased wi th increasing methanol concentration in the eluent. This anomalous ret ention behaviour was tentatively explained by possible ternary complex formation: cyclodextrin-solute-methanol. Stepwise regression analysis proved that the steric parameters of solutes have the highest impact on their retention on the polymer layers.