Determination of the 144Ce/238U ratio in spent nuclear fuels using the double isotope dilution technique associated with thermal ionization mass spectrometry measurements.

CE was hyphenated to MC-ICP-MS in a glove box to measure isotope ratios of actinides and lanthanides in spent nuclear fuel.

Depuis une vingtaine d’années, l’analyse isotopique de haute précision d’éléments minéraux essentiels endogènes dans les milieux biologiques a connu un essor considérable et montré sa potentialité comme nouveau marqueur de métabolisme, comme outil de diagnostic/pronostic précoce de maladies ou pour explorer de nouvelles approches pour le suivi de patients. Des variations infimes de compositions isotopiques d’éléments, tels que le calcium (Ca), le fer (Fe), le cuivre (Cu) et le zinc (Zn), susceptibles de se produire lors de la (dé)régulations de processus métaboliques dans lesquels ils sont impliqués, ont ainsi pu être mises en évidence grâce aux avancées techno-logiques récentes de la spectrométrie de masse. La « métallomique isotopique » est désormais une discipline qui a pour vocation l’exploitation de la distribution différentielle des isotopes d’éléments stables comme marqueur de conditions pathologiques. Cette discipline récente est très prometteuse en tant que nouvelle sonde de maladies et ouvre la voie à de nombreuses perspectives de développement. Over the past twenty years, high-precision isotopic analysis of endogenous essential mineral elements in biological media has been considerably developed and has shown its potential as a new marker of metabolism, as a tool for the early diagnosis/prognosis of diseases or to explore new approaches for patient monitoring. Minute variations in isotopic compositions of elements, such as calcium (Ca), iron (Fe), copper (Cu) and zinc (Zn), which may occur during the (de)regulation of metabolic processes in which they are involved, have thus been revealed owing to recent technological advances in mass spectrometry. “Isotopic metallomics” is now a discipline that aims to exploit the differential distribution of isotopes of stable elements as a marker of pathological conditions. This recent discipline shows great promise as a new disease probe and opens the way for many developments.

We developed a model based on Boundary-Element-Method to describe the tip-assisted electric field enhancement under laser illumination. The nanometric distribution of enhanced field is at the basis for an interpretation of near-field laser ablation applications.

The determination of the isotopic and elemental composition of nuclear samples is essential for the validation of neutronic codes and for the management of nuclear materials, particularly as the multi-recycling of Pu is considered in France. A capillary electrophoresis multicollector inductively coupled plasma mass spectrometry (CE-MC-ICP-MS) method for the measurement of actinides (U, Pu, Am, Cm) and of lanthanide fission products (Nd, Sm, Eu, Gd) isotope ratios in spent nuclear fuel samples was developed. This method allowed the determination of isotope ratios for the elements of interest with relative standard deviations and relative errors in the per-mil (0.1%) range. The CE-MC-ICP-MS results were in accordance with the ones obtained by two-step chromatography followed by offline measurement with mass spectrometry with a reduction of sample quantities and of liquid waste by a factor of at least 100. The application of CE-MC-ICP-MS developments to the design and fabrication of analytical microsystems could provide new miniaturized tools for the determination of isotopic and elemental compositions of nuclear samples.

Isotopic composition of elements was determined by applying a deconvolution method that we developed to electrospray mass spectra of the associated chemical species.

Online monitoring or in-situ isotopic analysis techniques in extreme environments are strategic tools in nuclear industry. A new optical method for performing isotopic analysis in solid samples at ambient pressure has been developed: Laser-Induced Breakdown self-Reversal Isotopic Spectrometry (LIBRIS). This method uses self-absorption of atomic or ionic resonance lines that are emitted from a non-uniform laser-induced plasma. It takes advantage of the fact that the spectral width of the absorption dip is much smaller than the spectral width of the emission line profile. Isotopic measurements were carried out on lithium samples by measuring the spectral position of the absorption dip that is shown to have a linear dependence on the 6Li isotopic abundance. Stand-off and real-time analysis can be performed without any sample preparation or pre-treatment. The effect of the laser wavelength, of the ambient gas and of the gate delay is investigated. Optimum conditions lead to a relative uncertainty of about 6% on the isotopic abundance measurement of 6Li. The influence of the spectral shifts due to Stark and Doppler effects on the performance of LIBRIS are discussed.

Capillary electrophoresis (CE) was hyphenated to multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) to determine the model age of a highly enriched uranium (HEU) sample using the 234U/230Th radiochronometer. The use of hydroxymethylbutyric acid (HMBA) as the CE electrolyte was investigated, and a complexation stacking method was developed to increase the thorium signal obtained. The age of the material was determined by measuring the 230Th content of the HEU sample using isotope dilution in conjunction with the CE-MC-ICP-MS protocol. The CE-MC-ICP-MS protocol and a standard offline protocol using gravitational chromatography both gave results in accordance within uncertainties with the production date of the HEU sample (March 1965). Liquid waste production was only of a few microliters with the use of CE. The hyphenation of CE with MC-ICP-MS render the measurement of the age of the HEU material in less than one day possible. Obtaining results in a timely fashion is of particular importance for nuclear forensics studies.

This article reviews the elemental and isotopic analysis of radionuclides using collision–reaction cell technology in ICP-MS applications.

An electrophoresis procedure, in which a sample is introduced into a capillary tube and the components are separated by the application of high voltage. Due to the large surface to volume ratio, cooling is more efficient, allowing use of higher voltages. As a result, separation occurs more quickly and sensitivity is increased. T he technique allows for separation of proteins, nucleic acids, and carbohydrates. Qeios · Definition, February 8, 2020

The U-236/U-238 isotope ratio is a widely used tracer, which provides information on source identification for safeguard purposes, nuclear forensic studies and environmental monitoring. This paper describes an original approach to determine U-236/U-239 ratios, below 10(-8), in environmental samples by combination of ICP-MS/MS for U-236/U-239 ratio and multiple collector ICPMS measurements for U-233/U-239 and U-234/U-235 isotope ratios. Since the hydride form of UO+ (UGH +) is less prone to occur than UH+, we were focused on the oxidised forms of uranium in order to reduce hydride based-interferences in ICP-MS/MS. Then, in-cell ion-molecule reactions with O-2 and CO2 were assessed to detect the uranium isotopes in mass-shift mode (Q1: U+ -> Q2: UO+). The performances in terms of UO+ sensitivity and minimisation of hydride form of UO+ were evaluated using five different desolvating systems. The best conditions, using an Apex Omega or an Aridus system, produced uranium oxide hydride rate ((UOH+)-U-235-O-160-H-1/(UO+)-U-235-O-16) of about 10(-7) with O-2 in the collision cell. The method was validated through measurements of two certified IRMM standards with U-236/U-239 isotope ratio of 1.245 x 10(-7) and 1.052 x 10(-8), giving results in agreement with certified reference values. The relative standard deviations on seven independent measurements for each standard were respectively of 1.5% and 6.2%. Finally, environmental samples corresponding to sediments from the radioactive contamination plume emitted by the Fukushima Daiichi Nuclear Power Plant accident were analysed after a well-established uranium chemical separation procedure. U-236/U-239 atomic ratios between 1.5 x 10(-8) and 7 x 10(-9) were obtained with a level accuracy lower than 20%.

Accurate isotope ratio determination was downscaled to the level of metal-containing protein fractions obtained from cell line lysates.

The impact of natural uranium (U) on differentiated human neuron-like cells exposed to 1, 10, 125, and 250 µM of U for seven days was assessed. In particular, the effect of the U uptake on the homeostatic modulation of several endogenous elements (Mg, P, Mn, Fe, Zn, and Cu), the U isotopic fractionation upon its incorporation by the cells and the evolution of the intracellular Cu and Zn isotopic signatures were studied. The intracellular accumulation of U was accompanied by a preferential uptake of 235U for cells exposed to 1 and 10 µM of U, whereas no significant isotopic fractionation was observed between the extra- and the intracellular media for higher exposure U concentrations. The U uptake was also found to modulate the homeostasis of Cu, Fe, and Mn for cells exposed to 125 and 250 µM of U, but the intracellular Cu isotopic signature was not modified. The intracellular Zn isotopic signature was not modified either. The activation of the non-specific U uptake pathway might be related to this homeostatic modulation. All together, these results show that isotopic and quantitative analyses of toxic and endogenous elements are powerful tools to help deciphering the toxicity mechanisms of heavy metals.

The radionuclide 129I is a long-lived fission product that decays to 129Xe by beta-particle emission. It is an important tracer in geological and biological processes and is considered one of the most important radionuclides to be assessed in studies of global circulation. It is also one of the major contributors to radiation dose from nuclear waste in a deep geological repository. Its half-life has been obtained by a combination of activity and mass concentration measurements in the frame of a cooperation of 6 European metrology institutes. The value obtained for the half-life of 129I is 16.14 (12) × 106 a, in good agreement with recommended data but with a significant improvement in the uncertainty.

In this study, a new analytical procedure based on isotachophoresis (ITP) coupled to a multi collector inductively coupled plasma mass spectrometer named Stop-Flow-ITP-MC-ICPMS is developed for exhaustive and high-precision multi-elemental isotopic characterization. We demonstrate that Stop-Flow-ITP makes it possible to stop the analytes migration several times for a duration compatible with the detector configuration changes without losing the separation performance. With this procedure, isotope ratio measurements of four lanthanides of interest for nuclear applications (Nd, Sm, Eu and Gd) were obtained with a reproducibility better than 0.4% in a single analysis with only 20 ng of each element. A nebulization interface between ITP and MC-ICPMS composed of a dual inlet spray chamber and a multiple flow stream valve made it possible to perform isotopic reference standard injections for on-line mass bias correction by the sample standard bracketing approach. The flexibility of the Stop-Flow-ITP-MC-ICPMS procedure opens the way to online determination of isotope ratio measurements of multiple analytes present in a sample in a single analysis.

In this work, amide-bonded columns packed with fully porous particles (FPP) and superficially porous particles (SPP) were evaluated to separate lanthanide-polyaminocarboxylic species by hydrophilic interaction liquid chromatography (HILIC), using two model samples of interest in nuclear and other industrial applications. We assessed the gains achieved by reducing the dimensions of the columns along with the size of the FPPs to sub-2 μm and by using sub-3 μm SPP-packed columns. The FPP-packed Acquity column (100 × 2.1 mm; 1.7 μm) performed better than the SPP-packed Accucore column (150 × 2.1 mm; 2.6 μm), with a separation that was two times more efficient and three times shorter, while generating around 30% less in effluent volumes. This column was also coupled simultaneously to electrospray ionisation mass spectrometry (ESIMS) and inductively coupled plasma mass spectrometry (ICPMS). The instrumental set-up was performed in a conventional laboratory, by taking into account the geometrical constraints existing in the laboratory dedicated to radioelement analysis. Furthermore, separation of the series of lanthanide (Ln) species was demonstrated for the first time thanks to the separation mode of hydrophilic interaction liquid chromatography.