Simultaneous Determination of Transuranium Radionuclides in Urine by Tandem Quadrupole ICP–MS/MS with Mass-Shift Mode Combined with Chemical Separation

The urine bioassay method for transuranium nuclides ( 237 Np, 239,240,241 Pu, 241 Am, and 244 Cm) 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 HNO 3 and 0.005–0.02 mol/L NaNO 2 when 242 Pu and 243 Am were selected as tracers for Np/Pu and Am/Cm yield monitoring. Based on their different reaction rates with O 2, 237 Np, 239,240,241 Pu, 241 Am, and 244 Cm in the same solution were simultaneously measured by ICP–MS/MS in the same run. The elimination efficiency of 238 U + tailing (7.43 × 10 –9 ), 238 U 1 H 16 O 2 + / 238 U 16 O 2 + (8.11 × 10 –8 ) and cross contamination of 241 Pu and 241 Am (<1%) were achieved using 10.0 mL/min He–0.3 mL/min O 2 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.