Determination of Trace Uranium in Nuclear Grade Sponge Zirconium  by Inductively Coupled Plasma Mass Spectrometry

In order to ensure the quantify control of the nuclear grade zirconium sponge, the inductively coupled plasma mass spectrometry(ICP-MS) was used to determine the trace uranium in the nuclear grade sponge zirconium. The sample was dissolved quickly by HNO3-HF solution. The analysis of the choices of isotope mass number and internal standard isotope, and the influence of matrix showed that the effective correction of matrix effect and the interference caused by the instrument drift can be accomplished, while 232Th was used as an internal standard. When the uranium standard stock solution with concentrations of 0.20 μg/g, 1.00 μg/g and 1.50 μg/g were respectively added to the samples, the recovery rates were between 94% and 99%, with corresponding maximum Relative Standard Deviation(RSD) of 5.1%, relative standard uncertainty of 5.9%. The detection limit was 0.001 μg/g. This method was employed to determine the actual sample, and the results meet the requirement of the uranium content in the nuclear grade sponge zirconium.