الخلاصة

The conditions for the diazitization coupling reaction of thymol with 4-aminoantipyrine at p H in the presence of Triton X-100 were studies . The reaction gave an intense water soluble yellow product that hss a maximum absorption at 454 nm and Ԑmax of 1.966 × 104 L.mole-1.cm-1. A linear correlation (1-14μg ml) was found between absorbance at λmax and concentration . The results obtained are both precise (RSD was better than 1.9) and accurate (relative error was better than -2.5). The coloured product was found to be 1:1 thymol : 4-aminoantipyrine . The stability constant of the product at room temperature were 0.75 x104 L.mole-1 . The proposed method was successfully applied to the determination of thymol in synthetic samples and in lastarine antiseptic pharmaceutical formulation