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The capacity of inclusion complex formation between a-, /9-, y- cyclodextrins(CDs) and various compounds, such as pH indicators, biostains, glycoside, amino acid, and fatty acids, was compared. Fatty acid was identified as the most suitable ligand for fractionation of CDs in terms of capacity and selectivity. The effects of complex formation conditions, such as, mixing ratio of CD and fatty acid, pH, ionic strength, and temperature, on the capacity of fatty acid-CD complex was also investigated. The carbon number of fatty acids was identified as the most significant factor determining the capacity and selectivity of inclusion complex formation of CDs. Capric acid(C,o) and palmitic acid(C,6) showed high specificity for a- and /9-CDs, respectively. Under the optimal conditions, the molar ratio of complex formed was found to be 1.0:2.6 for a-CD/capric acid and 1.0:1.9 for /3-CD/palmitic acid. X-ray diffraction and infrared spectrum of the formed inclusion complex were analyzed. The changes of enthalpy(L-1) of the inclusion complex formation reaction was evaluated by differential scanning calorimetry, showed that the reaction was endothermic.
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