Ultratrace and isotope ratios analyses of some radionuclides by ICP-MS

Extensive work is under way using High Resolution-ICP-MS for Sr-90, U-234, U-235, U-238, Pu-239, Pu-40, and Am-241 detection. Sample preparation procedures based on liquid-liquid extraction and ion exchange chromatography were developed. Sr, U. Pu. and Am were separated from their matrix and concentrated to improve the power of detection in the mass spectrometer. A microconcentric nebulizer with a desolvation introduction system (Ardius) is used. Instrumental limits of detection using Sr and U standard solutions are 0.01 ppt and 0.006 ppt for Sr and U, respectively. A study is presented on the mass interferences for the specified radionuclides. In the environmental samples investigated the Sr-90/Sr-86 isotope ratio is 6.02 x 10(-9) and for Pu-240/Pu-239 the isotope ratio is 0.17.