Determination of bismuth in sea-water by electrothermal atomic absorption spectrometry after liquid–liquid extraction and micro-volume back-extraction

Abstract

A method for the determination of bismuth at ng l^–1 levels in sea-water is described. Bismuth is extracted into xylene as the dithiocarbamate complex and subsequently back-extracted into 100 µl of nitric acid for determination by electrothermal atomic absorption spectrometry (ETAAS). The high efficiency of extraction and back-extraction allows bismuth to be concentrated about 25000-fild with a combined single extraction and back-extraction. The back-extracted solution is suitable for the determination of bismuth by ETAAS. Detection limit for Bi is 0.27 mg l^–1 based on a 3300-fold preconcentration. The concentration of bismuth in coastal sea-water was found to be 1.6 ng l^–1 by the proposed method. The accuracy of the results was assessed by comparison with those obtained by other analytical techniques.