New Application of Chromotropic Acid for the Determination of Some Sulphonamides in their Pharmaceutical Preparations

The formation of the azo-dye using chromotropic acid as a coupling agent was applied to the determination of five sulphonamides. The spectrophotometric studies as well as microanalysis of the studied sulphonamides- chromotropic acid azo dyes revealed the existence of the 1:1 coupling product. The absorbance of the formed azo dye is measured at 510 nrn, and has a large molar absorptivity (e = 2.87 - 3.29 × 104 1 mol−1cm−1). Beer's law was obeyed over the concentration range 0.5-9.0 µg ml−1. The assay results of pharmaceutical formulations showed good accuracy and precision over the concentration range used. The proposed method avoids time-consumption, extraction process and temperature control.