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 (3σ) for cadmium were 0.026 and 0.02 µg 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%.