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.
Department of Chemistry, The George Washington University, Washington, D.C. 20052, USA.
Craig S
CS
Westphal
John A
JA
McLean
Shelly J
SJ
Hakspiel
William E
WE
Jackson
David E
DE
McClain
Akbar
A
Montaser
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