Determination of Propranolol Hydrochloride by Fluorescence Spectrometry Based on Competitive Inclusion Reaction

A method of fluorescence spectrometry based on competitive inclusion action was proposed for the determination of propranolol hydrochloride. In a solution of pH 8.4 the weak fluorescence emitted by neutral red was found to be enhanced significantly upon the addition of appropriate amount of β-cyclodextrin, due to formation of an inclusion complex. Furthermore, the fluorescence intensity (measured at λex 465 nm and λem 580 nm) of the above mentioned reaction system was found to be reduced by the addition of propranolol hydrochloride due to its substitution of β-CD from the inclusion complex and the extent of reduction of the fluorescence intensity was found to keep linear relationship with the values of mass concentration of propranolol hydrochloride in the range of 0.10-20 mg·L-1, with value of detection limit (3s/k) of 6 μg·L-1. Hence, proprandol hydrochloride can be determined by measuring the reduction of fluorescence intensity of the reaction system. Recovery and precision of the method were tested, giving values of recovery in the range of 97.4%-100%, and RSD′s (n=6) in the range of 0.78%-1.5%. Substantial samples were analyzed by the proposed method, giving results in agreement with those obtained by the conventional fluorospectrometric method.