DETERMINATION OF CADMIUM IN VEGETABLES BY DERIVATIVE FLAME ATOMIC-ABSORPTION SPECTROMETRY WITH THE ATOM TRAPPING TECHNIQUE

A method is described for the determination of cadmium by derivative f lame atomic absorption spectrometry with a modified water-cooled stain less-steel atom trapping tube. The detection limit and sensitivity of the proposed method were improved by two and three orders of magnitude over those of conventional flame absorption spectrometry, with 1-3 mi n collection times, respectively. The characteristic concentration (fo r a derivative absorbance of 0.0044) and detection limit (3 sigma) for cadmium were 0.026 and 0.02 mu g l(-1), respectively, for a 1 min col lection time and a 2 mV min(-1) sensitivity range setting. The method was applied to the determination of cadmium in vegetable samples with a recovery range of 85.9-114%.