Abstract: An equation for the determination of equilibrium association constant (K_A) of cyclodextrin inclusion complex with fluorescence anisotropy was derived and used to determine K_Aof pyrene-β-cy-clodextrin inclusion complex satisfactorily. The existing form of inclusion complex and the host-guest interaction were discussed based on the derived equation along with the curve of fluorescence anisotropy versus cyclodextrin concentration for guest/cyclodextrin system. The possibility of application β-cyclodextrin in the analysis of metal ion using naphthalene derivative as a ligand was predicted.

Key words: Fluorescence anisotropy, Cyclodextrin inclusion complex, Association constant