Determination of Selenium in Natural Water by AAS after Solvent Extraction Preconcentration

The method described in this paper is based on the use of diethyldithiocarbamate (DEDC) to complex the trace selenium from the natural waters, with subsequent separation of the complex by solvent extraction and quantification by graphite furnace-atomic absorption spectrometer. The concentration coefficient is 10 3. The limit of detection is 0.01 ppb for 250 ml of sample. The precision (RSD) at the 10-ng level is better then 5%. The recovery is 96.6% (93.5-99.6%). Accuracy of results was assessed by independent, analytical techniques (ICP-MS). Comparison of results of GF-AAS and ICP-MS analysis of natural water samples indicates good agreement.