Simultaneous Determination of Transuranium Radionuclides in Urine by Tandem Quadrupole ICP-MS/MS with Mass-Shift Mode...

The urine bioassay method for transuranium nuclides (²³⁷Np, ^239,240,241Pu, ²⁴¹Am, and ²⁴⁴Cm) is needed to quickly assess the potential internal contamination in emergency situations. However, in the case that the analysis of multiple radionuclides is required in the same sample, time-consuming/tedious sequential analytical procedures using multiple chromatographic separation resins would have to be employed for the separation of every single radionuclide. In this work, a rapid method for the simultaneous determination of transuranium nuclides in urine was developed by using triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS) combined with a single DGA resin column. The chemical behaviors of Np/Pu and Am/Cm on the DGA resin were consistent in 8-10 mol/L HNO₃ and 0.005-0.02 mol/L NaNO₂ when ²⁴²Pu and ²⁴³Am were selected as tracers for Np/Pu and Am/Cm yield monitoring. Based on their different reaction rates with O₂, ²³⁷Np, ^239,240,241Pu, ²⁴¹Am, and ²⁴⁴Cm in the same solution were simultaneously measured by ICP-MS/MS in the same run. The elimination efficiency of ²³⁸U⁺ tailing (7.43 × 10^-9), ²³⁸U¹H¹⁶O₂⁺/²³⁸U¹⁶O₂⁺ (8.11 × 10^-8) and cross contamination of ²⁴¹Pu and ²⁴¹Am (<1%) were achieved using 10.0 mL/min He-0.3 mL/min O₂ even if the eluate was directly measured without any evaporation. The detection limits of transuranium nuclides were at the femtogram level, demonstrating the feasibility of ICP-MS/MS for simultaneous transuranic radionuclides urinalysis. The developed method was validated by analyzing the spiked urine samples.