The resonance nonlinear scattering intensity of procaine hydrochloride solution is weak. Whenβ-cyclodextrin was added to the procaine hydrochloride solution and formed an inclusion complex, the nonlinear scattering intensity was enhanced greatly. The intensity of the resonance nonlinear scattering increased with an increase inβ cyclodextrin concentration. In this work, the interaction ofβ cyclodextrin and procaine hydrochloride in aqueous solution was studied by the resonance nonlinear scattering technology. The new methods for the determination of the inclusion constant ofβ-cyclodextrin have been developed by using the frequency doubling scattering, second- order scattering, frequency tripling scattering and 3/2 multiple frequency scattering technology. The determination results were in correspondence with those of the spectrophotometric, fluorescence and resonance Rayleigh scattering methods. Therefore, the resonance nonlinear scattering can be used as a new technology for the determination of theβcyclodextrin inclusion constant.

Key words: procaine hydrochloride, cyclodextrin, RESONANCE SCATTERING, CLATHRATES, SPECTROPHOTOMETRY, FLUOROSPECTROPHOTOMETRY