STUDY OF SPECTROPHOTOMETRIC CHARACTERISTICS OF THE CHARGE TRANSFER COMPLEX OF TAURINE DRUG WITH 7,7,8,8-TETRACYANOQUINODIMETHANE

A new spectrophotometric method was developed for the determination of taurine using 7,7,8,8-tetracyanoquinodimethane (TCNQ). The method was based on the formation of charge transfer (CT) complex of this drug as n-electron donor with the π-acceptor TCNQ. TCNQ was found to react with taurine to produce a kind of yellow complex. The spectrum obtained for taurine/TCNQ system showed the maximum absorption band at a wavelength of 420 nm. The formation of such complex was also confirmed by both infrared and ¹H NMR measurements. Different variables affecting the reaction were studies and optimized. Beer’s law was obeyed in a concentration limit of 1~9 µg mL^-1 for taurine. R.S.D. was less than 1.5%, and average recovery was over 100.3%. The stoichiometry of the complex was found to be 1:1 ratio by Job’s and straight line methods between the donor and the acceptor. The thermodynamic standard reaction quantities of the complex between the donor and the acceptor were estimated. The developed method could be applied successfully for the determination of the studied compound in the pharmaceutical dosage form with a good precision and accuracy compared to official and reported method as revealed by t- and F-tests.

Keywords:
taurine; 7,7,8,8-tetracyanoquinodimethane (TCNQ); charge transfer (CT) complex; spectrophotometry