Sequential extraction-spectrofluorimetric determination of lead and cadmium using cryptands

Abstract

A spectrofluorimetric method for the determination of ultratrace amounts of lead and cadmium is described based on the sequential extraction of the ternary ion-association complexes formed between the cation, a cryptand as the ligand and eosin as a counter ion. A linear working range from the detection limit (0.5 ng ml^–1) to 250 ng ml^–1 of lead and to 150 ng ml^–1 of cadmium was obtained. The relative standard deviation was 2–4%. The proposed method has been applied successfully to the determination of lead and cadmium in zinc metals and soft drinks.