Determination of thallium in river sediment by flow injection on-line sorption preconcentration in a knotted reactor coupled with electrothermal atomic absorption spectrometry

A flow injection on-line sorption preconcentration electrothermal atomic absorption spectrometric (ETAAS) method mas developed for the determination of thallium, The Tl3+-tetramethplenedithiocarbamate (pyrrolidinedithiocarbamate) complex formed in strongly acidic medium (0-3 mol l(-1) HNO3, 0-3 mol l(-1) H2SO4, 0-2.5 mol l(-1) HClO4 or 0-2 mol l(-1) HCl) is sorbed on the inner malls of a PTFE knotted reactor (100 cm x 0.5 mm id) and quantitatively eluted with 45 mu l of ethanol, The ETAAS determination is performed in parallel with the preconcentration of the next sample, Using a preconcentration time of 30 s and a sample loading rate of 4.8 mi min(-1), an enhancement factor of 27 is obtained in comparison with direct injection of 45 pi of aqueous solution, The adsorption efficiency is 51%. The detection Limit (3s) is 0.015 mu g l(-1) and the precision (RSD) is 2.9% for 0.4 mu g l(-1) TI (It = II), The accuracy of the method is demonstrated by the analysis of a Community Bureau of Reference certified reference material 320 river sediment (indicative value for thallium concentration).