Determination of the binding constant for the inclusion complex between procaine hydrochloride and beta-cyclodextrin by capillary electrophoresis

The apparent electrophoretic mobilities of procaine hydrochloride (μ_i) in a series of concentration of β-cyclodextrin were measured directly by capillary electrophoresis technology. A new mathematical treatment method is proposed, which based on the fact that the molar ratio of the inclusion complex was 1:1 established by spectrophotometry. Using the proposed method, the binding constant of the inclusion complex of procaine hydrochloride with β-cyclodextrin can be obtained easily. The determination result was in correspondence with those of the spectrophotometric and fluorescence methods.