Determination Of Uranium In Urine Research Articles

The development of flow injection technique for rapid uranium determination in urine samples

Today much attention has been paid to precise determination of actinide elements in various biological samples. The importance of actinide bioassay is caused by their radiological hazard due to the internal exposure. The present research is devoted to the development of a flow injection extraction chromatography (FI-EC) as an analytical procedure for rapid determination of uranium in urine by ICP-MS. The developed FI-EC-ICPMS system includes automated radiochemical separation based on the use of UTEVASpec extraction chromatography resin followed by immediate ICP-MS measurement. Microwave digestion is applied to decompose urine samples prior to the FI-EC-ICPMS measurement. The system automatically removes matrix substances, thus, overcomes problem of matrix effect during ICP-MS measurement. Only few cm3 of urine are required for a single uranium analysis because of a low detection limit of the ICP-MS method. The developed FI-EC-ICPMS system is fully automated and virtually does not require handwork. By the FI-EC-ICPMS method uranium determination could be performed within 8 min per urine sample.

Determination of uranium in urine - measurement of isotope ratios and quantification by use of inductively coupled plasma mass spectrometry.

For analysis of uranium in urine determination of the isotope ratio and quantification were investigated by high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS). The instrument used (ThermoFinniganMAT ELEMENT2) is a single-collector MS and, therefore, a stable sample-introduction system was chosen. The methodical set-up was optimized to achieve the best precision for both the isotope ratio and the total uranium concentration in the urine matrix. Three spiked urine samples from an European interlaboratory comparison were analyzed to determine the (235)U/(238)U isotope ratio. The ratio was found to be in the range 0.002116 to 0.007222, the latter being the natural uranium isotope ratio. The first ratio indicates the abundance of depleted uranium. The effect of storage conditions and the stability for the matrix urine were investigated by using "real-life" urine samples from unexposed persons in the Netherlands. For samples stored under refrigeration and acidified the results (range 0.8 to 5.3 ng L(-1) U) were in the normal fluctuation range whereas a decrease in uranium concentration was observed for samples stored at room temperature without acidification.

Determining picogram quantities of uranium in urine by isotope dilution inductively coupled plasma mass spectrometry. Comparison with α-spectrometry

An accurate and simple method has been developed for the determination of uranium in urine using inductively coupled plasma mass spectrometry (ICP-MS). Isotope dilution analysis was applied using the long-lived uranium nuclide 233U as a spike in 1.3-fold diluted urine samples. To avoid matrix effects and salt depositions in the interface region of the instrument a prototype concentric-flow nebulizer with a mini cyclonic spray chamber was used at a reduced sample uptake rate of 0.3 ml min−1. The method was evaluated by comparison with α-spectrometry, as well as by analysis of National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 2670, Toxic Metals in Freeze Dried Urine, for which published results of isotope dilution thermal ionization mass spectrometry (TIMS) and radiochemical neutron activation analysis (RNAA) measurements are available. ICP-MS and α-spectrometry yielded consistent results (Wilcoxon, p = 0.87). The ICP-MS mean value (±95% confidence interval) of 143 ± 10 pg ml−1 obtained for the SRM 2670 agreed with the reported RNAA value of 130 ± 18 pg ml−1 at the 95% confidence interval; however, they exceeded the reported TIMS value of 113 ± 3 pg ml−1. The proposed method provides a means for determining uranium in unexposed subjects as well as in those considered to be exposed. Potential exposure to uranium amongst employees of UNHCR in western Kosovo was assessed.

Determination of uranium in urine by inductively coupled plasma mass spectrometry with pneumatic nebulization

An analytical method using inductively coupled argon plasma mass spectrometry with pneumatic nebulization sample introduction for the determination of uranium in urine is described. The urine samples were diluted 1+19 (1% HNO3 in Milli-Q water) before analysis. Standard additions calibration with iridium (193Ir) as an internal standard was used to compensate for undesirable matrix effects. The additions to the diluted samples were 0.1, 0.5, 1.0 and 2.0 ng l–1, equivalent to 2, 10, 20 and 40 ng l–1in undiluted urine. The detection limit of the method is 0.32 ng l–1, which is sufficiently low to measure uranium in non-exposed subjects. The precision at the 8.9 ng l–1 level was 3.9% (RSD), and at the 28.9 ng l–1 level 2.0%. The recovery for 20 ng l–1 added to ten different samples was 101.5%. Urine samples from 18 non-exposed subjects were analysed. The mean concentration found was 16.1 ng l–1 (median=15.1 ng l–1) with 14.9 ng l–1 (median=13.5 ng l–1) for male and 17.2 ng l–1 (median=17.6 ng l–1) for female subjects.

Flow injection method for determination of uranium in urine and serum by inductively coupled plasma mass spectrometry

The uranium concentration in urine of a population that is not occupationally exposed to uranium compounds is in the range 1–40 ng l −1 with a median around 10 ng l −1. This is analytically challenging for routine analysis because at such low levels it is difficult to prevent contamination during sample preparation. The method presented here is based on sample introduction via a flow injection analysis system and inductively coupled plasma mass spectrometric detection, and requires virtually no sample preparation, except for acidification of the urine sample with a few drops of HNO 3 The analysis is fully automated and fast with an analysis time of 60 s per sample. The lower limit of detection is 1.5ng l −1. Memory and matrix effects may be decreased by adding 1 g l −1 of a surfactant (Triton-X 100) to the carrier stream. The validity of the results is demonstrated through measurement of standard reference materials, standard dilution experiments and, at higher concentrations, by comparison with results obtained by an independent method based on laser induced fluorescence.

Investigation of the direct determination of uranium in plasma and urine by inductively coupled plasma mass spectrometry

The determination of uranium in urine is used for the control of subjects at occupational risk particularly in the nuclear power industry. As the levels of uranium in the urine and plasma of healthy subjects without occupational risks are very low, a very sensitive analytical method is needed. Inductively coupled plasma mass spectrometry was studied for this purpose. It is a direct, reproducible and sensitive method which would be suitable for the control of uranium in subjects at occupational risk but not, under the conditions adopted, for precise quantification of normal plasma and urine levels, which are lower than the limit of quantification of 35 ng l −1.

Spectrophotometric method for the determination of uranium in urine.

A method was developed in which 1 ..mu..g of uranium can be separated directly from 50 to 200 cm/sup 3/ of urine by anion exchange and then determined spectrophotometrically with arsenazo III.