ON-LINE PRECONCENTRATION SYSTEM WITH FAAS DETECTION FOR DETERMINATION OF CADMIUM

A procedure for the preconcentration and determination of cadmium in aqueous samples was developed in the flow system coupled to flame atomic absorption spectrometer. Cadmium is quantitatively preconcentrated in borate buffer as the complex with Tiron (4,5-dihydroxy-1,3benzendisulfonic acid) onto a microcolumn packed with macroporous anion-exchange resin AG MP-1, eluted by a stream of 2 mol l-1 nitric acid and introduced directly into the nebuliser. A detection limit of 0.9 µg L-1 is obtained using a time-based technique for 5 min preconcentration and an enrichment factor of 98 could be achieved. The method was applied to the analysis of natural waters.