Optimization of elemental selenium (Se(0)) determination in yeasts by anion-exchange HPLC-ICP-MS.

An analytical method was developed for the speciation of elemental selenium (Se(0)) in selenized yeasts by anion-exchange HPLC-ICP-MS after its chemical transformation into SeSO by reaction with sodium sulfite. The presence of Se(0) in the yeasts was further confirmed by single-particle ICP-MS. Indeed, Se nanoparticles, if present, are expected to be, at least partly, Se(0).

Advanced nanomedicine characterization by DLS and AF4-UV-MALS: Application to a HIV nanovaccine.

Nanoformulations are complex systems where physicochemical properties determine their therapeutic efficacy and safety. In the case of nanovaccines, particle size and shape play a crucial role on the immune response generated. Furthermore, the antigen's integrity is also a key aspect to control when producing a nanovaccine.

Potential of lead elemental and isotopic signatures for authenticity and geographical origin of Bordeaux wines.

Lead concentrations and lead isotope ratios of 43 authentic Bordeaux wines from prestigious châteaux and 14 suspicious Bordeaux origin were determined to evaluate their potential for authenticity and geographical origin assessment. Results have shown that the total Pb concentrations in Bordeaux wines drastically decreased over the previous 50 years with a clear shift of isotopic signatures towards geogenic values corresponding to an overall trend of European environmental lead monitoring. The Pb isotopic ratios determined in both series of samples clearly demonstrated that suspicious Bordeaux wines displayed Pb isotopic signatures statistically distinctive from those obtained for authentic wines.

Strontium elemental and isotopic signatures of Bordeaux wines for authenticity and geographical origin assessment.

The Sr/Sr ratio and Sr concentrations of 43 authentic Bordeaux wines from the world's most prestigious châteaux are presented in the context of their relation to the geographical origin of wine and authenticity. The results demonstrate relatively narrow spans of variabilities observed for Sr/Sr ratio and Sr concentrations in authentic Bordeaux wines, which can be used with reasonable certainty as specific parameters for identifying regional wineries. For comparison, a set of imitated Bordeaux wines was studied for Sr isotopic and elemental compositions.

Cr(VI) and Cr(III) in milk, dairy and cereal products and dietary exposure assessment.

Milk, dairy and cereal products are the main contributors to total chromium (Cr) dietary exposure in France (up to 42% for children), but there have been no assessments regarding dietary exposure to Cr(VI) or Cr(III) to date. To assess dietary exposure, total chromium and Cr(VI) were determined in 68 different brands and origins of milk, dairy and cereal products. Cr(VI) was not detected in these samples despite the very high sensitivity of the method used.

Study of the presence of micro- and nanoparticles in drinks and foods by multiple analytical techniques.

A variety of food and drink samples (n = 21) were analyzed to evaluate the presence of (nano-) particles in their composition. After assessment of the sample pre-treatment step, a fast screening analysis was performed for drinks by Dynamic Light Scattering showing particles from 10 to 300 nm that could correspond to organic or metallic NPs. Metallic NPs were identified in foods by Single-Particle mode Inductively Coupled Plasma Mass Spectrometry and Asymmetrical Flow Field-Flow Fractionation coupled to Multiangle Laser Light Scattering and Inductively-Coupled Plasma Mass Spectrometry.

Total As and As speciation from worldwide collected red wine samples.

Total As and As speciation were measured in 147 red wines collected worldwide by ICP-MS and HPLC-ICP-MS, respectively. The samples included mid-priced to prestigious wines with vintages covering a period of almost 50 years. Total As concentration ranged from below 0.

Screening of TiO and Au nanoparticles in cosmetics and determination of elemental impurities by multiple techniques (DLS, SP-ICP-MS, ICP-MS and ICP-OES).

Cosmetics are part of the daily life of most of the people. Thus, a complete characterization of the products we applied in our skin is necessary. In this work, an analytical investigation of a wide variety of cosmetics from the point of view of total element content and metallic nanoparticles (NPs) has been performed.

Effect of water table variations and input of natural organic matter on the cycles of C and N, and mobility of As, Zn and Cu from a soil impacted by the burning of chemical warfare agents: A mesocosm study.

A mesocosm study was conducted to assess the impact of water saturation episodes and of the input of bioavailable organic matter on the biogeochemical cycles of C and N, and on the behavior of metal(loid)s in a soil highly contaminated by the destruction of arsenical shells. An instrumented mesocosm was filled with contaminated soil taken from the "Place-à-Gaz" site. Four cycles of dry and wet periods of about one month were simulated for 276days.

Optimization and validation of the methods for the total mercury and methylmercury determination in breast milk.

The objective of the work was to develop and validate methods for the total Hg and methylmercury (MeHg) in breast milk that could be further used to obtain first data on chemical contamination of French breast milk. For total Hg determination, the potential of two techniques, namely Advanced Mercury Analyzer (AMA) and ICP MS, was compared. For MeHg determination, ICP MS detection associated to a quantification by isotopic dilution was used and the potential of a preliminary separation by gas or liquid chromatography was evaluated and discussed.

Optimisation of selective alkaline extraction for Cr(VI) determination in dairy and cereal products by HPIC-ICPMS using an experimental design.

This study presents the optimisation through an experimental design then the validation of a method to determine Cr(VI) in certain foodstuffs by high-performance ionic chromatography with inductively coupled plasma mass spectrometry. This method is free from interferences possibly associated with chloride and organic or inorganic carbon. Analytical performances assessed by the accuracy profile method were satisfactory in terms of linearity, specificity, sensitivity, accuracy, repeatability and intermediate precision.

Thiomonas sp. CB2 is able to degrade urea and promote toxic metal precipitation in acid mine drainage waters supplemented with urea.

The acid mine drainage (AMD) in Carnoulès (France) is characterized by the presence of toxic metals such as arsenic. Several bacterial strains belonging to the Thiomonas genus, which were isolated from this AMD, are able to withstand these conditions. Their genomes carry several genomic islands (GEIs), which are known to be potentially advantageous in some particular ecological niches.

Cr(VI) speciation in foods by HPLC-ICP-MS: investigation of Cr(VI)/food interactions by size exclusion and Cr(VI) determination and stability by ion-exchange on-line separations.

A method has been developed for the specific and sensitive determination of Cr(VI) in foods. First, the interactions between Cr(VI) and the matrices were investigated by size-exclusion HPLC-ICP-MS (SEC-ICP-MS). Evidence was found for the complexation of Cr(VI) potentially present with the ligands.

Metagenomic insights into microbial metabolism affecting arsenic dispersion in Mediterranean marine sediments.

Microorganisms dwelling in sediments have a crucial role in biogeochemical cycles and are expected to have a strong influence on the cycle of arsenic, a metalloid responsible for severe water pollution and presenting major health risks for human populations. We present here a metagenomic study of the sediment from two harbours on the Mediterranean French coast, l'Estaque and St Mandrier. The first site is highly polluted with arsenic and heavy metals, while the arsenic concentration in the second site is below toxicity levels.

Evaluation of hexavalent chromium extraction method EPA method 3060A for soils using XANES spectroscopy.

Hexavalent chromium (Cr(VI)) occurrence in soils is generally determined using an extraction step to transfer it to the liquid phase where it is more easily detected and quantified. In this work, the performance of the most common extraction procedure (EPA Method 3060A) using NaOH-Na(2)CO(3) solutions is evaluated using X-ray absorption near edge structure spectroscopy (XANES), which enables the quantification of Cr(VI) directly in the solid state. Results obtained with both methods were compared for three solid samples with different matrices: a soil containing chromite ore processing residue (COPR), a loamy soil, and a paint sludge.

Selenium exposure in subjects living in areas with high selenium concentrated drinking water: results of a French integrated exposure assessment survey.

Background: Selenium is an essential element which can be toxic if ingested in excessive quantities. The main human exposure is food. In addition, intake may be boosted by consumption drinking water containing unusual high selenium concentration.

Taxonomic and functional prokaryote diversity in mildly arsenic-contaminated sediments.

Arsenic-resistant prokaryote diversity is far from being exhaustively explored. In this study, the arsenic-adapted prokaryotic community present in a moderately arsenic-contaminated site near Sainte-Marie-aux-Mines (France) was characterized, using metaproteomic and 16S rRNA-encoding gene amplification. High prokaryotic diversity was observed, with a majority of Proteobacteria, Acidobacteria and Bacteroidetes, and a large archaeal community comprising Euryarchaeaota and Thaumarchaeota.

Unsuspected diversity of arsenite-oxidizing bacteria as revealed by widespread distribution of the aoxB gene in prokaryotes.

In this study, new strains were isolated from an environment with elevated arsenic levels, Sainte-Marie-aux-Mines (France), and the diversity of aoxB genes encoding the arsenite oxidase large subunit was investigated. The distribution of bacterial aoxB genes is wider than what was previously thought. AoxB subfamilies characterized by specific signatures were identified.

Partitioning of metal species during an enriched fuel combustion experiment. speciation in the gaseous and particulate phases.

Combustion processes are the most important source of metal in the atmosphere and need to be better understood to improve flue gas treatment and health impact studies. This combustion experiment was designed to study metal partitioning and metal speciation in the gaseous and particulate phases. A light fuel oil was enriched with 15 organometallic compounds of the following elements: Pb, Hg, As, Cu, Zn, Cd, Se, Sn, Mn, V, Tl, Ni, Co, Cr, and Sb.