Determination of depleted uranium in urine via isotope ratio measurements using large-bore direct injection high efficiency nebulizer-inductively coupled plasma mass spectrometry.
Inductively coupled plasma mass spectrometry (ICP-MS), coupled with a large-bore direct injection high efficiency nebulizer (LB-DIHEN), was utilized to determine the concentration and isotopic ratio of uranium in 11 samples of synthetic urine spiked with varying concentrations and ratios of uranium isotopes. Total U concentrations and (235)U/(238)U isotopic ratios ranged from 0.1 to 10 microg/L and 0.0011 and 0.00725, respectively. The results are compared with data from other laboratories that used either alpha-spectrometry or quadrupole-based ICP-MS with a conventional nebulizer-spray chamber arrangement. Severe matrix effects due to the high total dissolved solid content of the samples resulted in a 60 to 80% loss of signal intensity, but were compensated for by using (233)U as an internal standard. Accurate results were obtained with LB-DIHEN-ICP-MS, allowing for the positive identification of depleted uranium based on the (235)U/(238)U ratio. Precision for the (235)U/(238)U ratio is typically better than 5% and 15% for ICP-MS and alpha-spectrometry, respectively, determined over the concentrations and ratios investigated in this study, with the LB-DIHEN-ICP-MS system providing the most accurate results. Short-term precision (6 min) for the individual (235)U and (238)U isotopes in synthetic urine is better than 2% (N = 7), compared to approximately 5% for conventional nebulizer-spray chamber arrangements and >10% for alpha-spectrometry. The significance of these measurements is discussed for uranium exposure assessment of Persian Gulf War veterans affected by depleted uranium ammunitions.
Westphal
Craig S
CS
Department of Chemistry, The George Washington University, Washington, D.C. 20052, USA.
McLean
John A
JA
Hakspiel
Shelly J
SJ
Jackson
William E
WE
McClain
David E
DE
Montaser
Akbar
A
D000336:Aerosols / Q000032:analysis; D006358:Hot Temperature; D006801:Humans; D007554:Isotopes / Q000032:analysis; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D008889:Military Personnel; D009330:Nebulizers and Vaporizers; D016273:Occupational Exposure / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States; D014501:Uranium / Q000652:urine*; D016482:Urinalysis / Q000379:methods*; D014857:Warfare
D000336:Aerosols; D007554:Isotopes; D014501:Uranium