Flame atomic absorption spectrometric determination of cadmium in biological samples using a preconcentration flow system with an activated carbon column and dithizone as a chelating agent

A combined flow atomic absorption spectrometric system was used to develop an efficient on-line preconcentration-solvent elution procedure for the determination of trace amounts of cadmium. The metal was preconcentrated as the dithizonate on a mini-column packed with activated carbon and eluted with isobutyl methyl ketone (4-methylpentan-2-one) into the nebulizer. A preconcentration factor of 40–130, equivalent to 3–12 ml of sample, was achieved by using a time-based technique. The detection limit obtained (3σ) ranged between 0.3 and 1.3 ng ml–1 and the relative standard deviation from 1.3 to 2.4% for a sample volume of 12 and 3 ml, respectively. The results obtained for the determination of cadmium in reference materials testify to the applicability of the proposed procedure to the analysis of biological materials.