Determination of U-236/U-238 and U-235/U-238 isotope ratios in human urine by inductively coupled plasma mass spectrometry

作者：Gray Patrick J; Zhang Lingsu; Xu Hanna; McDiarmid Melissa; Squibb Katherine; Centeno Jose A^*

来源：Microchemical Journal, 2012, 105: 94-100.

DOI：10.1016/j.microc.2012.07.004

• Uranium
• Depleted uranium
• Uranium isotope ratio
• Urine
• Inductively coupled plasma mass spectrometry

Isotopic ratios of urinary uranium (U) provide a decisive tool in diagnosing a patient's potential exposure to depleted uranium (DU). This study investigated the measurement of urinary U-236/U-238 and U-235/U-238 ratios of ultra trace concentrations using a sector field inductively coupled plasma mass spectrometer (ICP-MS). Uranium was separated from the urinary matrix and pre-concentrated by co-precipitation with calcium and magnesium after addition of ammonium hydroxide. The precipitates were collected, dissolved and analyzed by ICP-MS. U-235/U-238 and U-236/U-238 ratios were measured using a desolvating sample introduction system and a sector field ICP-MS. These ratios were accurately measured in samples containing as low as 5 ng L-1 U. U-236 measurement was hindered by abundance sensitivity limitations and uranium hydride ((UH)-U-235) formation. Measured U-235/U-238 and U-236/U-238 ratios were about 7 x 10(-3) and < 5 x 10(-6), respectively, in urine samples from patients not exposed to DU. The U-235/U-238 ratio was consistently about 2 x 10(-3) in 12 urine samples from patients with embedded fragments of DU, while the corresponding ratio of U-236/U-238 ranged from 9 x 10(-6) to 33 x 10(-6). This wide range in U-236/U-238 ratios might suggest different sources of depleted uranium in those DU-urine samples. It is proposed that U-235/U-238 and U-236/U-238 ratios are 7 x 10(-3) and <5 x 10(-6), respectively, in urine samples from individuals not exposed to DU, and 2 x 10(-3) and 7 x 10(-6), respectively, in urine samples from DU-exposed individuals. Published by Elsevier B.V.

• 出版日期2012-11