Immobilization of controlled Pu:Am ratio on actinide-specific affinity monolith support developed in capillary and coupled to inductively coupled plasma mass spectrometry.

The objective of this work was to develop an actinide-specific monolithic support in capillary designed to immobilize precise Pu:Am ratios and its coupling to inductively coupled plasma mass spectrometry (ICP-MS) for immobilized metal affinity chromatography applications. This format offers many advantages, such as reducing the sample amount and waste production, which are of prime importance when dealing with highly active radioelements. Four organic phosphorylated-based monoliths were synthesized in situ through UV photo-polymerization in capillary and characterized.

Determining the selectivity of a tetra-phosphorylated biomimetic peptide towards uranium in the presence of competing cations through the simultaneous coupling of HILIC to ESI-MS and ICP-MS.

A cyclic tetra-phosphorylated biomimetic peptide (pS1368) has been proposed as a promising starting structure to design a decorporating agent of uranyl (UO) due to its affinity being similar to that of osteopontin (OPN), a target UO protein in vivo. The determination of this peptide's selectivity towards UO in the presence of competing endogenous elements is also crucial to validate this hypothesis. In this context, the selectivity of pS1368 towards UO in the presence of Ca, Cu and Zn was determined by applying the simultaneous coupling of hydrophilic interaction chromatography (HILIC) to electrospray ionization (ESI-MS) and inductively coupled plasma (ICP-MS) mass spectrometry.

Innovative ICP-MS/MS Method To Determine the Cs/Cs Ratio in Low Activity Environmental Samples.

The Cs/Cs isotopic ratio is a powerful tool for tracing the origin of radioactive contamination. Since the Fukushima accident, this ratio has been measured by mass spectrometry in several highly contaminated environmental matrices mainly collected near nuclear accident exclusion zones and former nuclear test areas. However, few data were reported at Cs environmental levels (<1 kBq kg).

Determination of the affinity of biomimetic peptides for uranium through the simultaneous coupling of HILIC to ESI-MS and ICP-MS.

Several proteins have been identified in the past decades as targets of uranyl (UO) in vivo. However, the molecular interactions responsible for this affinity are still poorly known which requires the identification of the UO coordination sites in these proteins. Biomimetic peptides are efficient chemical tools to characterize these sites.

Cytoplasmic aggregation of uranium in human dopaminergic cells after continuous exposure to soluble uranyl at non-cytotoxic concentrations.

Uranium exposure can lead to neurobehavioral alterations in particular of the monoaminergic system, even at non-cytotoxic concentrations. However, the mechanisms of uranium neurotoxicity after non-cytotoxic exposure are still poorly understood. In particular, imaging uranium in neurons at low intracellular concentration is still very challenging.

Hyphenation of capillary electrophoresis with MC-ICP-MS - A novel tool for uranium age dating.

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 U/Th 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 Th content of the HEU sample using isotope dilution in conjunction with the CE-MC-ICP-MS protocol.

A new method for determining U/U isotope ratios in environmental samples by means OF ICP-MS/MS.

The U/U 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/U ratios, below 10, in environmental samples by combination of ICP-MS/MS for U/U ratio and multiple collector ICPMS measurements for U/U and U/U isotope ratios. Since the hydride form of UO (UOH) 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.

Isotopic variations of copper at the protein fraction level in neuronal human cells exposed in vitro to uranium.

The study of isotopic variations of endogenous and toxic metals in fluids and tissues is a recent research topic with an outstanding potential in biomedical and toxicological investigations. Most of the analyses have been performed so far in bulk samples, which can make the interpretation of results entangled, since different sources of stress or the alteration of different metabolic processes can lead to similar variations in the isotopic compositions of the elements in bulk samples. The downscaling of the isotopic analysis of elements at the sub-cellular level, is considered as a more promising alternative.

Reconstruction of uranium and plutonium isotopic signatures in sediment accumulated in the Mano Dam reservoir, Japan, before and after the Fukushima nuclear accident.

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in Japan resulted in a major release of radionuclides into the environment. Compared to other radionuclides, few studies have investigated the fate of actinides in the environment. Accordingly, this research investigates the Pu composition in soil samples collected in paddy fields before and after the accident.

Impact of uranium uptake on isotopic fractionation and endogenous element homeostasis in human neuron-like cells.

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 U 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.

Precise U and Pu Isotope Ratio Measurements in Nuclear Samples by Hyphenating Capillary Electrophoresis and MC-ICPMS.

Precise isotopic and elemental characterization of spent nuclear fuel is a major concern for the validation of the neutronic calculation codes and waste management strategy in the nuclear industry. Generally, the elements of interest, particularly U and Pu which are the two major elements present in spent fuel, are purified by ion exchange or extractant resins before off-line measurements by thermal ionization mass spectrometry. The aim of the present work was to develop a new analytical approach based on capillary electrophoresis (CE) hyphenated to a multicollector inductively coupled plasma mass spectrometer (MC-ICPMS) for online isotope ratio measurements.

A new procedure for high precision isotope ratio determinations of U, Cu and Zn at nanogram levels in cultured human cells: What are the limiting factors?

The monitoring of isotopic fractionations in in vitro cultured human cell samples is a very promising and under-exploited tool to help identify the metabolic processes leading to disease-induced isotopic fractionations or decipher metabolic pathways of toxic metals in these samples. One of the limitations is that the analytes are often present at small amounts, ranging from tens to hundreds of ng, thus making challenging low-uncertainty isotope ratio determinations. Here we present a new procedure for U, Cu and Zn purification and isotope ratio determinations in cultured human neuron-like cells exposed to natural U.

Evidence of isotopic fractionation of natural uranium in cultured human cells.

The study of the isotopic fractionation of endogen elements and toxic heavy metals in living organisms for biomedical applications, and for metabolic and toxicological studies, is a cutting-edge research topic. This paper shows that human neuroblastoma cells incorporated small amounts of uranium (U) after exposure to 10 µM natural U, with preferential uptake of the U isotope with regard to U. Efforts were made to develop and then validate a procedure for highly accurate n(U)/n(U) determinations in microsamples of cells.

Multi-elemental Gd, Eu, Sm, Nd isotope ratio measurements by liquid chromatography coupled to MC-ICPMS with variable Faraday cup configurations during elution.

The high-precision isotopic characterization of actinides and fission products in nuclear samples is fundamental for various applications such as the management of spent nuclear fuel or the validation of neutronic calculation codes. However multi-elemental isotope ratio measurements by mass spectrometric techniques are hampered by the presence of both spectral and non-spectral interferences as complex sample matrices are encountered in such topics, but also due to the lack of high precision mass spectrometers able to cover the entire mass spectrum. This work describes a new LC-MC-ICPMS approach allowing simultaneous high-precision and multi-elemental isotope ratio measurements of four fission products of interest for nuclear issues (Nd, Sm, Eu, Gd) within a single elution run.

Separation and analysis of lanthanides by isotachophoresis coupled with inductively coupled plasma mass spectrometry.

This study is a large project initiated by the French Nuclear Agency, and concerns the development of a new electrolyte system for the separation of lanthanides by isotachophoresis. This new system is based on a leading electrolyte that incorporates 2-hydroxy-2-methylbutyric acid as complexing agent. The optimization of separation conditions (complexing agent concentration, pH, capillary dimensions, injection conditions, and current intensity) performed by experiments on a commercial capillary instrument with contactless conductivity detection, which allows to improve the separation of 13 lanthanides (La to Lu, except Pm and Ho).