Uranium urine

Hooper, F.J., Squibb, K.S., Siegel, E.L., McPhaul, K., Keogh, J.P. (1999). Elevated urine uranium excretion by soldiers with retained uranium shrapnel. Health Phys. 77 512-19. 

Lippmann M, Ong LDY, Harris WB. 1964. The significance of urine uranium excretion data. IndHyg J (January-February)43-54. 

DETERMINATION OE ACTINIDES DETERMINATION OE LOW-CONCENTRATION URINE URANIUM 235/238 ISOTOPE RATIOS... 

For individuals with high urine uranium concentrations (1.0 pg/L uranium or more in urine) such as from uranium milling workers, wounded combatants whose tissues were embedded with pieces of steel hardened with depleted uranium, or those with similar circumstances, a simple analysis of a 1/10 dilution of urine with a standard introduction system on most ICP-MS instruments may be used to derive an acceptably accurate uranium isotope ratio. As an example. Figure 23.1 illustrates the results obtained from a urine sample spiked with 1.0 pg/L uranium, diluted 1/10 with 5% nitric acid, and analyzed with a well-optimized single collector magnetic sector ICP-MS instrument. However, in the vast majority of urine samples, the uranium concentrations are far below 1.0 pg/L so that accurate determinations are a challenge in most cases [2]. 

Despite instrumental improvements, problems remain for urine uranium isotope ratio analyses at low concentrations by ICP-MS. The most accurate and precise instruments determine only the ratios of detected ions. If ions are produced as a result of introduction of a sample with a matrix that inherently causes formation of isobaric mass interferences within the mass window of one or more of the isotopes to be determined, then the resulting inaccurate elemental isotope ratios will accurately and precisely reflect a determination of the combined elemental isotope and interference ions that were counted indiscriminately by the detector. 

The sample preparation techniques discussed here, which utilize chelation resin SPE columns, were developed in order to maximize urine uranium isotope ratio accuracy, while consuming as little preparation time as possible. Removal of hydrophobic organic substances... 

Low U/ U isotope ratio QC samples are prepared by quantitatively pipetting an aliquot of a depleted U standard such as NBL CRM 115, U005, and an enriched standard such as U020 or equivalent (if licensing is available for enriched uranium standards) into the characterized base urine described above. Equivalent standards may be obtained from IRMM. The spiked-urine uranium isotope ratio is characterized to verify the expected versus measured ratio. The isotope ratio, if different than expected, is verified by calculation as the mass-weighted average of the natural uranium isotope ratio and the spiked depleted uranium isotope ratio. 

Studies show that the main sites of uranium deposition ate the renal cortex and the Hvet (8). Uranium is also stored in bones deposition in soft tissues is almost negligible. Utanium(VI) is deposited mostly in the kidneys and eliminated with the urine whereas, tetravalent uranium is preferentially deposited in the Hvet and eliminated in the feces. The elimination of uranium absorbed into the blood occurs via the kidneys in urine, and most, - 84%, of it is cleared within 4 to 24 hours (8). 

Animal studies indicate that the primary toxic effect of uranium exposure is on the kidney, with particular damage to the proximal tubules. Functionally, this may result in increased excretion of glucose and amino acids. Structurally the necrosis of tubular epithelium leads to formation of cellular casts in the urine. If exposure is insufficient to cause death from renal failure, the mbular lesion is reversible with epithelial regeneration. Although bone is the other major site of deposition, there is no evidence of toxic or radiocarcinogenic effects to bone or bone marrow from experimental studies. ... 

After inhalation exposure, the primary route of excretion is in the feces following ciliary clearance from the lungs to the gastrointestinal tract (Wrenn et al. 1981). Fecal excretion may account for as much as 97% of total excretion (Fisher et al. 1983). Higher levels of thorium-230 were excreted in the feces by active crushermen (uranium mill workers exposed to uranium ore dust in the crusher building) compared to retired workers or controls (Fisher et al. 1983). Levels of thorium-230 in the urine were comparable to those of retired workers, and the levels in both were significantly greater than controls. 

As discussed before, quadrupole based ICP-MS allows multi-element determination at the trace and ultratrace level and/or isotope ratios in aqueous solutions in a few minutes as a routine method with detection limits of elements in the sub pgml-1 range and a precision for determined trace element concentration in the low % range (RSD - relative standard deviation). The precision for isotope ratio measurements varies between 0.1% and 0.5% RSD. This isotope ratio precision is sufficient for a multitude of applications, e.g., for evidence of contamination of sample with depleted or enriched uranium in urine (this technique is used in the author s laboratory in a routine mode14) or the isotope dilution technique for the quantitative determination of trace element and species concentration after doping the sample with enriched isotope spikes. 

Table 9.39 Results of determination of uranium concentration and isotope ratio measurements by LA-ICP-SFMS on several urine samples (n = 3).

Benkhedda, K., Epov, V. N., and Evans, R. D., Flow-injection technique for determination of uranium and thorium isotopes in urine by inductively coupled plasma mass spectrometry, Anal. Bioanal. Chem., 381, 1596-1603, 2005. 

Kuwabara, J., Tolmachyov, S., and Noguchi, H., The development of flow injection technique for rapid uranium determination in urine, J. Nucl. Sci. Technol., Suppl. 3, 556-559, 2002. 

Uranium. About 50% of plasma uranium is bound, as the uranyl ion, to bicarbonate, which is filtered by the glomerulus. As a result of acidification in the proximal tubule, the bicarbonate complex dissociates, followed by reabsorption of the bicarbonate ion the released UO22"1" then becomes attached to the membrane of the proximal tubule cells. The resultant loss of cell function is evidenced by increased concentrations of glucose, amino acids, and proteins in the urine. 

Because the drug and the mobilized metals are excreted via the urine, the drug is contraindicated in anuric patients. Nephrotoxicity from EDTA has been reported, but in most cases this can be prevented by maintenance of adequate urine flow, avoidance of excessive doses, and limitation of a treatment course to 5 or fewer consecutive days. EDTA may result in temporary zinc depletion that is of uncertain clinical significance. An experimental analog of EDTA, calcium disodium diethylenetriaminepentaacetic acid (DTPA), has been used for removal ("decorporation") of uranium, plutonium, and other heavy radioisotopes from the body. 

To measure uranium isotopes in a water or urine sample with a mass spectrometer. 

Uranium in nature may be measured either radiometrically or chemically because the main isotope - 238U - has a very long half life (i.e., relatively few of its radioactive atoms decay in a year). Its isotopes in water and urine samples usually are at low concentrations, for which popular analytical methods are (1) radiochemical purification plus alpha-particle spectral analysis, (2) neutron activation analysis, (3) fluorimetry, and (4) mass spectrometry. The radiochemical analysis method is similar in principle to that of the measurement of plutonium isotopes in water samples (Experiments 15 and 16). Mass spectrometric measurement involves ionization of the individual atoms of the uranium analyte, separation of the ions by isotopic mass, and measurement of the number of separated isotopic ions (see Chapter 17 of Radioanalytical Chemistry text). 

Ullmann synthesis, ] 15 Unsaturated acid chlorides, acylation, 49 Uranium derivatives, 154 Uranyl ions, 108 Urea, with azothiazoles. 111 to thiazolyl urea, 56 see also Thiazolyl urea Urine, 2-aminothiazoles in, 85 metabolite in, 85... 

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