Abstract:
BACKGROUNDThe Sr and Nd isotopic compositions of a sample depend on its initial isotopic ratios, the ratios between the parent nuclide and daughter product, and the decay time. Due to their significance for the tracing of reservoirs, they were widely applied in the geological studies. Traditional cation resin was applied to purify Sr and Nd for isotope analysis, which involved the organic reagent and pH adjustment. The complex chemical procedure was time-consuming. In recent years, the appearance of special resins has made it easy to separate these elements. However, due to the influence of sulfates and other factors, the use of special resins is limited.
OBJECTIVESTo shorten the chemical purification time of Sr and Nd, and to avoid the damage of sulfate ions on the Sr and REE specific resins, we proposed a new chemical purification method, where multiple columns were utilized.
METHODSThe method combines cationic resin and special resin to realize the rapid separation of Sr and Nd and can extend the using time of special resin. The experiment uses cationic resin, Sr special resin and LN rare earth special resin to analyze the basalt standard BCR-2.
RESULTSThe recoveries of Sr and Nd with this method were larger than 90%. The 87Sr/86Sr and 143Nd/144Nd isotope ratios were 0.705016±0.000016 (n=36, 1SD) and 0.512624±0.000012 (n=39, 1SD), respectively, which were in coincidence with the values previously reported by TIMS method within the analytical error. The complied 87Sr/86Sr and 143Nd/144Nd isotope ratios obtained TIMS were 0.705000-0.705023 and 0.512630-0.512650, respectively. The 85Rb/86Sr and 147Sm/144Nd rations of the purified Sr and Nd solution were less than 0.01 and 0.001, respectively.
CONCLUSIONSThe proposed chemical purification procedure can efficiently separate Rb, Sr, Sm and Nd, and realize the accurate analysis of Sr and Nd isotopes.
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