TEMPERATURE EFFECT ON OVERLOADED ELUTION PROPERTIES OF CYCLODEXTRINS IN REVERSED-PHASE CHROMATOGRAPHY

The temperature effects on the retention properties of native cyclodex trins (CDs) are studied under overloaded reversed-phase liquid chromat ographic conditions. For all native CDs a strong temperature dependenc e is observed. The analysis of adsorption isotherms confirms a differe nt retention mechanism for alpha-CD compared to that for the larger be ta-, gamma-CDs. The strong variations in the determined isotherm param eters due to the temperature variations are discussed in terms of the solvophobic theory and structural organization. Analysis of the entrop y contribution to the isotherm obtained by a Van't Hoff plot suggests higher ordering when the CDs are bound to the stationary phase. Finall y, the influence of the studied temperature effect on errors encounter ed in isotherm determination using the ECP method is analysed.