USING P-ANISIDINE FOR SPECTROPHOTOMETRIC DETERMINATION OF THYMOL BY OXIDATION COUPLING REACTION

A rapid and sensitive spectroscopic method was developed for the determination of thymol in its pure form and in its pharmaceutical preparations. The method relied on oxidative coupling reactions. With the oxidizing agent N-chlorosuccinimide and the p-anisidine reagent in a basic sodium hydroxide medium to form a stable, blue-colored product that gives maximum absorption at a wavelength of 603 nm. The molar absorptivity was 1.35 x 104 l/mol.cm, and the concentrations followed Beer’s law within the linear range 0.5-20 µg/ml. The accuracy of the method was 103.76%, while the compatibility was less than 0.28%. The LOD and LOQ values were 0.0300 and 0.100, respectively. The rate of the stability constant for the formed complex was 7.18 × 106 L/mol, which indicates the good stability of the compound. The method was successfully applied to pharmaceutical preparations in the form of mouthwash and ointment.