Sensitive inductively coupled plasma atomic emission spectrometric determination of cadmium by continuous alkylation with sodium tetraethylborate

Abstract

Continuous flow generation of volatile Cd species using NaBEt₄ as a means of gaseous sample introduction into an inductively coupled plasma atomic emission spectrometry (ICP-AES) instrument has been investigated in detail. The assumed generation of CdEt₂ is discussed and critically evaluated in terms of the sensitivity, selectivity and accuracy of the corresponding ICP-AES determination of low levels of Cd. The proposed method for the determination of Cd by ICP-AES using NaBEt₄ provided detection limits of 0.4 ng ml^–1, which are ten times better than those of conventional nebulization ICP-AES. A precision of ± 1.4% at the 50 ng ml^–1 level of Cd was observed. Interference studies have been carried out, which demonstrated high selectivity of the proposed method. This method has been applied to the determination of low levels of Cd by ICP-AES in samples of sea-water and tea infusions. Satisfactory validation of the results obtained has been provided by electrothermal atomic absorption spectrometric analysis of the same samples.