Abstract: The structure of the inclusion complex of Oneothera Biennis oil by β-cyclodextrin was characterized with IR, UV- Vis and differential thermal analysis technique.The influence of the type, concentration of the heavy metal cation and the temperature on the stability of β-cyclodextrin inclusion complex was investigated. The results showed that the absorbance of Oneothera Biennis oil and its inclusion complex by β-cyclodextrin increased with the concentration of metal cation and the temperature. When the reaction was carried out for 2 .5h at 120℃, ΔA/A0 for the two substrates increased to 1.69 and 1.2 times of the original values, respectively. When reacted for 8h at 0.08mol/L Pb2+,ΔA/A0 for the two substrates became 2.29 and 0.49 times of the original values, respectively, indicating a greatly increased stability of the inclusion complex to the variation of the metal cation concentration and the temperature relative to the Oneothera Biennis oil.

Key words: Oneothera Biennis oil, β-Cyclodextrin inclusion complex, stability