Spectrophtometric determination of Thymol in Various SampleS of Mouth Washes by coupling with Diazotized 4-bromo aniline


Abstract A simple, rapid and sensitive spectrophotometric method for determination of microgram amounts of Thymol in pure form and in mouth wash preparations was described.The method is based on a diazotization and coupling reaction between Thymol and diazotized 4-bromo aniline in basic medium to form an intense yellow water-soluble dye that is stable, which shows maximum absorption at 464nm. Beer’s law is obeyed over the concentration range of(0.6-7.2) μg.ml-1 of Thymol, with a molar absorptivity of 3.0284×104 l mol-1 cm-1, and Sandell sensitivity index of 0.004 μg/cm2 The method does not resort to temperature control or to solvent extraction. The optimum conditions for all colour development are described and proposed methods were successfully applied to the determination of Thymol in mouth wash preparations. The common excipients and additives did not interfere in this method.