Indirect atomic absorption spectrometric determination of sulphonamides in pharmaceutical preparations and urine by continuous precipitation

Abstract

Two atomic absorption spectrometric methods are proposed for the determination of sulphonamides in pharmaceutical preparations, based on continuous precipitation with copper and silver ions in a flow injection manifold. The precipitate is formed by injecting the cation into a carrier containing the sample and is subsequently retained on a stainless-steel filter. Various filters of different chamber inner volume, pore size and filtration areas were tested. By continuous precipitation, sulphonamides can be determined in the range 2.5–35 µg ml^–1, with a relative standard deviation between 1.5 and 3% and a sampling frequency of 100–150 h^–1. The copper method is more selective than the silver method and can be applied to the determination of sulphonamides in urine.