Comparison of three chelating resins for the preconcentration of Cd, Cu and Pb in the analysis of waters by flame atomic absorption spectrometry

The analytical characteristics of solid-phase extraction method to preconcentrate Cd, Cu and Pb in waters were studied. The 8-hydroxyquinoline immobilized onto TSK Toyopearl vinyl copolymer, 7-(4-ethyl-1-methyloctyl)-hydroxyquinoline adsorbed onto C18 and C18 modified with sodium diethyldithiocarbamate chelating were evaluated. The optimized extraction conditions were: pH 7, sample flow rate of 1 mL, elution flow rate of 1 mL min− 1, sample volume of 50 mL and eluent volume of 5 mL. The three studied materials can be used for the determination of Cd, Pb and Cu in water with repeatability and intermediate precision between 10 and 15%, and recovery between 90 and 111%. However, the 8-hydroxyquinoline immobilized onto TSK Toyopearl vinyl copolymer was the best material because of: a) the best detection limits for Pb, Cd and Cu are achieved, b) only one eluent is needed for the elution of the three metals and c) it showed a higher time durability.