Evaluation of an immobilised macrocyclic material for on-line column preconcentration and separation of cadmium, copper and lead for electrothermal atomic absorption spectrometry Original Research Article

The determination of trace amounts of Cd, Cu and Pb in riverine, estuarine, sea water and in urine samples, using a flow injection on-line preconcentration procedure coupled with electrothermal atomic absorption spectrometry, was investigated. The sorption material used consists of macrocyclic ligand immobilised on a silica gel support. The sample at pH 1.6 is loaded onto a 50 μl column for a specific time interval. The column is then washed with a dilute nitric acid solution (pH 3) and emptied by pumping air through the column. The column is eluted with 40 μl of 2.5 mol l−1 nitric acid solution and the eluate introduced into the electrothermal atomiser. Detection limits (3σ) of 0.8, 46 and 20 ng l−1 were obtained for Cd, Cu and Pb, respectively. The accuracy of the procedure was tested with water and urine certified reference materials.