Potentiometric and atomic absorption spectrometric determination of sulfonamides in pharmaceutic preparations

Potentiometric and atomic absorption spectrometric (AAS) methods are described for the determination of various sulfonamides in tablets, suspensions, and injections, based on reactions with silver and copper ions. The methods involve direct titration at pH 8, using either a graphite electrode in which silver and copper sulfides have been precipitated, or ion selective electrodes to monitor the potential change. AAS measurements of the excess metal ions after metal-sulfonamide reaction are also reported. Results compare favorably with those obtained using USP XIX procedures. The methods described are selective, simple and precise.