Application of first derivative fluorescence spectrometry to the simultaneous determination of paracetamol and salicylamide in pharmaceuticals

Abstract The determination of paracetamol and salicylamide in the presence of each other was performed by means of a first-derivative spectrofluorimetric method with a “zero-crossing” technique of measurement. The reported method is based on the oxidation of the paracetamol with potassium hexacyanoferrate (III) to give a fluorescent substance. The quantitative ranges are 80–640 μg l−1 for paracetamol and 3.2–150.4 μg l−1 for salicylamide, with relative standard deviations of 3.1 and 1.3 μg l−1, respectively. Good results, both in terms of sensitivity and reproducibility, were obtained in the determination of paracetamol and salicylamide in the presence of each other by using this technique. The method was applied to several pharmaceutical formulations containing the drugs and was found to be satisfactory.