Cloud Point Extraction and Preconcentration of Silver and Cadmium Using Schiff Base Prior to Flame Atomic Absorption Spectrometric Determination

Abstract

Cloud point methodology was successfully used for the extraction of trace amounts of silver and cadmium as a prior step to their determination by flame atomic absorption spectrometry. Silver and cadmium reacts with Schiff base benzylbis- (thiosemicarbazone) as chelating agent in a surfactant solution yielding a hydrophobic complex, which then is entrapped in surfactant micelles. After phase separation, based on the cloud point the mixture and dilution of the surfactant-rich phase with methanol containing 0.1 M HNO₃, the enriched analytes were determined by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions and preconcentration 60 mL of sample in the presence of 0.17 % Triton-X-114 the enhancement factors of 140 and 60 and detection limits of 0.04 ng mL^-1 and 0.08 ng mL^-1 were obtained for silver and cadmium, respectively. The proposed method was applied satisfactory to the determination of Ag and Cd in natural water samples.