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 flame atomic absorption spectrometry with a modified water-cooled stainless-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 min collection times, respectively. The characteristic concentration (for 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 collection 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%.