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The recent expansion in the use of nanomaterials in various fields has led to a growing concern over their impacts on environmental systems. Accurate detection, quantification, characterization, and tracking of the nanoparticles are essential for assessing the ecological risks and their implications for environmental health. Inductively coupled plasma mass spectrometry (ICP-MS) operated in single-particle mode is an attractive analytical tool for quantification and sizing very small nanoparticles in aqueous suspensions. The ICP-MultiQuad-MS/MS can rapidly detect (including highly interfered elements) and characterize a large number of particles, determine size and size distributions, the particle number concentration in a sample, and the elemental mass concentration of both dissolved and particulate species. This paper provides the first systematic review of the ICP-MultiQuad-MS/MS to perform NPs analysis applied to different structures and compositions while simultaneously comparing them with the current state of the art of ICP-(CRC)-MS available. This study is done on composite nanomaterials with different shapes for elements with high sensitivity and no interference, like Au, Ag, and Pt, and elements with high interferences and lower sensitivity, like Fe, Si, and Ti.

Oxidative stress is known to play a major role in the pathogenesis of inflammatory bowel diseases (IBDs), and, in particular, superoxide dismutase (SODs) defenses were shown to be weakened in patients suffering from IBDs. SOD mimics, also called SOD mimetics, as low-molecular-weight complexes reproducing the activity of SOD, constitute promising antioxidant catalytic metallodrugs in the context of IBDs. A Mn(II) complex SOD mimic (Mn1) based on an open-chain diaminoethane ligand exerting antioxidant and anti-inflammatory effects on an intestinal epithelial cellular model was shown to experience metal exchanges between the manganese center and metal ions present in the biological environment (such as Zn(II)) to some degrees. As the resulting complexes (mainly Zn(II)) were shown to be inactive, improving the kinetic inertness of Mn(II) complexes based on open-chain ligands is key to improve their bioactivity in a cellular context. We report here the study of three new Mn(II) complexes resulting from Mn1 functionalization with a cyclohexyl and/or a propyl group meant to limit, respectively, (a) metal exchanges and (b) deprotonation of an amine from the 1,2-diaminoethane central scaffold. The new manganese-based SOD mimics display a higher intrinsic SOD activity and also improved kinetic inertness in metal ion exchange processes (with Zn(II), Cu(II), Ni(II), and Co(II)). They were shown to provide anti-inflammatory and antioxidant effects in cells at lower doses than Mn1 (down to 10 μM). This improvement was due to their higher inertness against metal-assisted dissociation and not to different cellular overall accumulations. Based on its higher inertness, the SOD mimic containing both the propyl and the cyclohexyl moieties was suitable for intracellular detection and quantification by mass spectrometry, quantification, that was achieved by using a 13C-labeled Co-based analog of the SOD mimics as an external heavy standard.

Palladium is recognized as a technologically critical element (TCE) because of its massive use in automobile exhaust gas catalytic converters. The release of Pd into the environment in the form of nanoparticles of various size and chemical composition requires an understanding of their metabolism by leaving organisms. We provide here for the first time a chemical speciation insight into the identity of the ligands produced or used by a plant Sinapis alba L. exposed in hydropony to Pd nanoparticles and soluble Pd (nitrate). The analytical method developed was based on the concept of 2D HPLC with parallel inductively coupled plasma mass spectrometry (ICP MS) and electrospray MS detection. Size exclusion chromatography – ICP MS of the plant extracts showed no difference between the speciation of Pd after the exposure to nanoparticles and after that to Pd2+ which indicated the reactivity and dissolution of Pd nanoparticles. A comparative investigation of the Pd speciation in a control plant extract spiked with Pd2+ and of an extract of a plant having metabolized palladium indicated the response of the Sinapis alba by the formation of a Pd–histidine complex. The complex was identified via Orbitrap MS; the HPLC-MS chromatogram produced two peaks at m/z 415.0341 each corresponding to a Pd–His2 complex. An investigation by ion-mobility MS revealed a difference in their collision cross section indicating that the complexes present varied in terms of spatial conformation. A number of other Pd complexes with different ligands (including nicotianamine) circulating in the plant were detected but these ligands were already observed in a control plant and their concentrations were not affected by the exposure to Pd.

International audience; Materials in direct contact with food should be monitored for the presence of species able to migrate into food. A direct method based on liquid extraction surface analysis nanoelectrospray mass spectrometry (LESA-nanoESI-MS) was developed for the analysis of the migrating species from a polymer film. Different types of molecules: post-polymerization residues, degradation products (oligomers resulting from polymer recycling, products of polymer oxidative degradation) and anti-oxidant additives (vitamin E) were demonstrated to be detected and identified, and determined quantitatively if relevant calibration standards are available. The method was validated by a comparison a standard method based on with bulk extraction mass spectrometry. It offers considerable advantages over the latter in terms of drastically reduced analysis time and solvent consumption. Also, LESA-nanoESI-MS produced simpler spectra (limited to compounds able to migrate into food) than Direct Analysis in Real Time (DART).

According to the European Water Framework Directive, environmental assessment of organic compounds should be made in whole-water samples, but due to their hydrophobicity and strong attraction to organic content these compounds can be found bound to suspended particle matter or in the dissolved fraction. In this work, the extraction of musk compounds was studied in whole-water samples exhibiting different amounts of dissolved organic carbon and suspended particulate matter using polyethersulfone preconcentration technique. Matrix effects in estuarine and wastewater (both influent and effluent) were evaluated for filtered and unfiltered samples. For unfiltered samples, estuarine water exhibited matrix effects

cited By 0; International audience; MXene as two dimensional (2-D) Titanium (III) Carbide (II) (Ti3C2Tx) nanosheets was synthesized and processed by etching bulk MAX phase Titanium (III) Aluminium Carbide (II) (Ti3AlC2) powders in HF solution. This material demonstrated an extraordinary efficiency for the removal of barium from synthetic produced/co-produced water. The synthesized nanosheet was characterized using field emission scanning electron microscopy (FE-SEM), the Brunauer, Emmett and Teller (BET) nitrogen surface area adsorption, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), particle size analysis and zeta potential. The effect of adsorption parameters such as adsorbent dosage, contact time, and initial barium concentration were investigated and the optimum parameters for maximum removal of barium have been investigated. The experimental adsorption equilibrium data were correlated by the Langmuir and Freundlich isotherms, while the sorption energy was calculated using Dubinin-Radushkevich (D-R) model. The kinetic data were analyzed using two kinetic models. Optimization of process variables including shaking speed, contact time, pH, and amount of MXene has been performed to determine the maximum adsorption capacity of barium from water. MXene has a combination of unique properties such as a large number of available active sites, hydrophilic surface, highly negative surface charge, chemical stability, reasonable surface area, and the possibility of cations intercalating through its layers. MXene showed a large sorption capacity, fast kinetics, enormous trace barium removal, and reversible adsorption properties which offer an efficient removal performance of barium with a capacity of 9.3 mg/g and removal efficiency reaching up to 100% under optimized conditions. © 2017 Elsevier B.V.

International audience; To achieve a “Good Environmental Status by 2015,” as demanded by the water framework directive, monitoring programs are needed to furnish data on target compounds. In this study, a first evaluation of influents and main emissions of 3 local wastewater treatment plants (WWTP) in the Adour estuary (southwest of France) was performed for 23 pollutants (10 musk fragrances, 5 alkylphenols, and 8 organometallics), as well as receiving estuarine water from the same area. High frequency of occurrence of these compounds was found in influents samples (musks: 22–100%; alkylphenols 11–100%; organometallics 0–100%) and effluents (musks: 0–100%; alkylphenols 0–100%; organometallics 0–100%). The removal efficiencies were calculated and varied from negative values up to 98% with the lowest values for synthetic musk compounds. Temporal variability of the target compounds also was studied, and a few tendencies were observed. Estimation of the daily output of each WWTP into the estuary also showed that galaxolide, nonylphenol, monobuthyltin, and inorganic mercury were the compounds discharged into the environment at the highest concentrations. Finally, the occurrence of these compounds in estuarine waters was evaluated; most of them were present at concentrations below the limits of quantification (musks: 0.53–41.5 ng/L; alkylphenols 3.4–410 ng/L; organometallics 0.02–0.70 ng/L) suggesting a low impact in the resulting receiving waters.

International audience; A high efficiency chromatographic separation on a porous graphitic carbon stationary phase was developed for a large-scale separation of selenium metabolites in Se-rich yeast prior to their identification by electrospray hybrid quadrupole trap/Orbitrap mass spectrometry (Orbitrap MSn). The reversed-phase (RP) separation mode offered distinctly higher separation efficiency than the hydrophilic ion interaction (HILIC) mode. The latter was nevertheless complementary and useful to validate the detection of several compounds. The method allowed the detection of 64 metabolites including 30 SeSe or SeS conjugates (3 triple S/Se/S ones) and 14 selenoethers. 21 previously unreported metabolites were detected on the basis of the selenium isotopic pattern usually matched with the sub-ppm mass accuracy. 9 of these metabolites were subsequently identified using the multi-stage high mass accuracy (

International audience; The aim of this work is to estimate background concentrations of organometallic compounds, such as tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPhT), diphenyltin (DPhT), monophenyltin (MPhT), methylmercury (MeHg), inorganic mercury (iHg) and diethyllead (Et2Pb) in the aquatic environment at the French national scale.Both water and sediment samples were collected all over the country, resulting in 152 water samples and 123 sediment samples collected at 181 sampling points. Three types of surface water bodies were investigated: rivers (140 sites), lakes (19 sites) and coastal water (42 sites), spread along the 11 French river basins. The choice of sites was made on the basis of previous investigation results and the following target criteria: reference, urban sites, agricultural and industrial areas. The analytical method was properly validated for both matrices prior to analysis, resulting in low limits of quantification (LOQ), good precision and linearity in agreement with the Water Framework Directive demands. The results were first evaluated as a function of their river basins, type of surrounding pressure and water bodies. Later, background concentrations at the French national scale were established for both water and sediment matrices, as well as their threshold, i.e., the concentration that distinguishes background from anomalies or contaminations. Background concentrations in water are ranging between

International audience; Laser ablation-ICP MS was optimized for the sensitive detection of selenoproteins in polyacrylamide gel and PVDF membrane after blotting. For this purpose, two interlaboratory reference samples were prepared: glutathione peroxidase band in the gel and on the membrane, respectively. The optimisation was carried out using two systems: 213 nm laser (Newwave) - Agilent 7500ce ICP MS, and a 1030 nm high repetition rate femtosecond laser with galvanometric optics (Novalase) - PE/SCIEX DRCII. Sensitivity and signal-to-noise ratio were benchmarked to those obtained for the same sample by a recently published method in a reference lab. The optimization allowed a 12-fold gain of the S/N ratio during ablation of gels and a 3.5-fold gain in the ablation of blots in comparison with the method using an essentially similar system published by the reference lab. The gain of S/N by increasing ablation surface using the high repetition rate laser was not as spectacular as expected (2.5-fold for the gels and 1.5-fold for the blots) as the background noise increased considerably when a larger surface is ablated due to selenoproteins peak tailing. The study allowed for the first time LA-ICP MS detection of selenoproteins (separated by gel electrophoresis) in human cell extracts with the selenium concentration at the 10 ng ml -1 level.

Chlamydomonas reinhardtii is a common model organism for investigation of metal stress. This green alga produces phytochelatins in the presence of metal ions. The influence of cadmium is of main interest, because it is a strong activator of phytochelatin synthase. Cell wall bound and intracellular cadmium content was determined after exposition to 70 µm CdCl(2), showing the main portion of the metal outside the cell. Nevertheless, imported cadmium was sufficient to cause significant changes in thiolpeptide metabolism and its transcriptional regulation. Modern analytical approaches enable new insights into phytochelatin (PC) distribution. A new rapid and precise UPLC-MS method allowed high-throughput PC quantification in algal samples after 1, 4, 24 and 48 h cadmium stress. Initially, canonic PCs were synthesized in C. reinhardtii during cadmium exposition, but afterwards CysPCs became the major thiolpeptides. Thus, after 48 h the concentration of the PC-isoforms CysPC(2-3) and CysGSH attained between 105 and 199 nmol g(-1) fresh weight (FW), whereas the PC(2-3) concentrations were only 15 nmol g(-1) FW. The relative quantification of γ-glutamyl transpeptidase (γ-GT) mRNA suggests the generation of CysPCs by glutamate cleavage from canonic PCs by γ-GT. Furthermore, a homology model of C. reinhardtii phytochelatin synthase was constructed to verify the use of crystal structures from Anabaena sp. phytochelatin synthase (PCS) for docking studies with canonical PCs and CysPCs. From the difference in energy scores, we hypothesize that CysPC may prevent the synthesis of canonical PCs by blocking the binding pocket. Finally, possible physiological reasons for the high abundance of CysPC compared with their canonic precursors are discussed.

International audience; The stereo-electronic control over bisadditions of conjugated polymers to fullerene (C60) is explored in the formation of alternating copolymers. The chemistry, resulting configuration, and properties of poly(3-hexylthiophene)- alt-C60 copolymers prepared by either classic pyrrolidine ring formation or an atom transfer radical addition are compared. Both routes result in controlled additions of polymers to C60. Extensive macromolecular modeling through PM6 methods indicate that there is no conjugation between P3HT and C60 in the systems studied. This along with 2D-NMR, AFM, and photovoltaic characterizations of the materials indicate the importance of the structure of the modified C60 and the nature of the linking group between C60 and P3HT segments in determining the morphology of the copolymers in the solid state. © 2009 Wiley Periodicals, Inc.

The knowledge-base of bottled water leachate is highly contradictory due to varying methodologies and limited multi-elemental and/or molecular analyses; understanding the range of contaminants and their pathways is required. This study determined the leaching potential and leaching kinetics of trace elements, using consistent comprehensive quantitative and semi-quantitative (79 elements total) analyses, and BPA, using isotopic dilution and MEPS pre-concentration with UHPLC-ESI-QTOF. Statistical methods were used to determine confounders and predictors of leaching and human health risk throughout 12days of UV exposure and after exposure to elevated temperature. Various types of water were used to assess the impact of water quality. Results suggest Sb leaching is primarily dependent upon water quality, not container type. Bottle type is a predictor of elemental leaching for Pb, Ba, Cr, Cu, Mn and Sr; BPA was detected in samples from polycarbonate containers. Health risks from the consumption of bottled water increase after UV exposure.

In a multi-well tracing test, one of the key parameters is the selection of an appropriate tracer molecule and its relative analytical process regarding the local environmental and operational constraints. Many tests in the past have been unsuccessful due to improper tracer selection. The first part of this presentation provides guideline data and advice on selecting the best possible tracers/markers and analytical processes for a tracing campaign according to the test’s main objective which may be linked to the inter-well network, connectivity/injectivity, flow allocation, residual oil saturation, etc.

cited By 14; International audience; Analysis of selenopeptides, isolated (and considered as pure) by 2D size-exclusion-reversed-phase HPLC, by capillary HPLC-ICP MS revealed a number of previously unreported Se-containing compounds. Their identity and origin were studied by the state-of-the art molecular mass spectrometric techniques including MALDI MS, oMALDI MS/MS and nanoLC-electrospray QTOF MS/MS. The research showed for the first time the possibility of loss of selenium from selenomethionine by degradation to vinylglycine and the formation of new Se peptides by methylation on carboxylic residues. The study substantiates claims for the use of the highest possible resolution HPLC for speciation studies. It raises concerns about misinterpretation of HPLC-ICP MS data on Se-speciation in selenised yeast since a number of peaks observed may be due to the formation of artefact compounds during some analytical procedures. © The Royal Society of Chemistry 2006.

cited By 4; International audience; Sediments from Bizerta lagoon were used in an experimental microcosm setup involving three scenarios for the bioremediation of anthracene-polluted sediments, namely bioaugmentation, biostimulation, and a combination of both bioaugmentation and biostimulation. In order to investigate the effect of the biotreatments on the benthic biosphere, 16S rRNA gene-based T-RFLP bacterial community structure and the abundance and diversity of the meiofauna were determined throughout the experiment period. Addition of fresh anthracene drastically reduced the benthic bacterial and meiofaunal abundances. The treatment combining biostimulation and bioaugmentation was most efficient in eliminating anthracene, resulting in a less toxic sedimentary environment, which restored meiofaunal abundance and diversity. Furthermore, canonical correspondence analysis showed that the biostimulation treatment promoted a bacterial community favorable to the development of nematodes while the treatment combining biostimulation and bioaugmentation resulted in a bacterial community that advantaged the development of the other meiofauna taxa (copepods, oligochaetes, polychaetes, and other) restoring thus the meiofaunal structure. The results highlight the importance to take into account the bacteria/meiofauna interactions during the implementation of bioremediation treatment.

International audience; Large volume injection (LVI)-in port silylation coupled to gas chromatography-mass spectrometry (GC-MS) for the determination of alkylphenols (APs) in water samples applying four different extraction approaches was evaluated. Among the variables studied for in-port derivatization, vent time, cryo-focusing temperature and the ratio solvent volume/N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) volume were optimized using an experimental design approach. Regarding the extraction techniques, different approaches previously optimized in the research group were tested. On the one hand different polymeric materials were tested: silicon rod (SR), polyethersulfone (PES) and polydimethylsiloxane (PDMS), the latter in the stir-bar sorptive extraction format (SBSE-PDMS). PES was chosen among the polymeric materials due to the higher recoveries (compared with SR) and lower price (compared to PDMS in the stir-bar sorptive extraction, SBSE-PDMS). Both MASE and PES protocols were selected at this point for further method validation and application to real samples. Finally, the developed methods were validated and applied to the determination of target analytes in various aqueous environmental matrices, including estuarine water and wastewater. Acceptable repeatability in the case of MASE (5-17%) and PES (7-21%) procedures and method detection limits (MDLs, 5-123 and 28-328ngL-1 for PES and MASE, respectively) were obtained for most analytes. In terms of apparent recoveries in the presence of matrix, estuarine and effluent samples showed no significant matrix effect (apparent recoveries in the 73-121% for PES and 74-128% for MASE), while a stronger matrix effect was observed for influent wastewater samples (98-132% for PES and 65-156% for MASE). Both MASE and PES extractions combined with LVI-in-port derivatization-GC-MS were applied to the determination of APs in the estuary of Bilbao (Gulf of Biscay, Spain).

cited By 2; International audience; A microcosm experiment was used to examine (1) the effects of different bioremediation schemes on degradation of anthracene and the structure of free-living marine nematodes in a lightly contaminated (4.5 μg g -1) sediment from Bizerte lagoon and (2) the responses of the nematode community upon an artificial spiking of a low dose anthracene (1 μg g-1). For that purpose sediment microcosms were incubated in laboratory for 40 days. Bioremediation techniques decreased the anthracene contamination, and interestingly, biodegradation were more efficient when anthracene was artificial supplied into the sediment suggesting that the addition of bioavailable anthracene stimulated the bacterial community to adjust towards a PAH-degrading community. Spiking with this low dose of anthracene provoked significant changes in the nematode community structure and abundance, with the elimination of specific species such as Mesacanthion diplechma, the decrease of the dominant species Oncholaimus campylocercoides and the increase in abundance of opportunistic species such as Spirinia parasitifera. This would suggest a low tolerance of the nematode community despite the presence of a weak anthracene contamination in the sediment that could have allow dominance of an anthracene tolerant nematode species. Anthracene toxicity was alleviated in biostimulation treatments, leading to a strong increase in nematode abundance, concomitantly with changes in the nematode community structure; Prochromadorella neapolitana became the most abundant species.

Background and Objectives Produced water for future reuse is a key component of Qatar's Water Security Grand Challenge (WSGC) and forward progress within the Grand Challenge is dependent on comprehensive characterization and potential risks. To date, only major compounds of produced waters are characterized. For safety reason, a global fingerprint of both natural and anthropogenic trace organic and inorganic constituents must be created before any treatment or reuse. The main objective of this innovative strategy is to reach an accurate, non-specific monitoring of organic and inorganic ultra-trace compounds by mass spectrometry. Methods Produced water samples were collected in Qatar's oil field from various Qatar's produced wells with a high water cut in order to evaluate the water quality and to select produced waters for further studies for treatment and reuse. To highlight the benefit of this innovative analytical approach, the study was focused on highly hydrophilic compounds which remain in the aqueous phase even after oil separation. Naphtenic acids, Fluorinated acids, BTEX biodegradation byproducts, halo acetic acids, and trace metals (Ni, Cr, Fe, Cd, U etc.) are related to produced water characteristics, oil and gas industry and well tubing. The quantifications were firstly completed by UHPLC-ESIqQqTOF Maxis HD (Bruker) and by ICP-MS Aurora Elite (Bruker). All analyses were performed in QEERI laboratories. The direct analyses of produced water were based on synergic used of ultra high pressure liquid chromatography, non-specific high resolution and inductively coupled plasma mass spectrometry. The development of robust, accurate and high end methods allows us to generate high quality data for immediate chemical information extraction, long term inter sample comparison and long term raw data storage for further studies. The in silico storage of water's nonspecific fingerprint is an interesting and promising alternative to long term storage of diluted media like water samples which are always critical. Results The current study was performed using Qatar's produced waters and on Congo and Angola's produced waters as reference waters. Despite the sub-ppb level quantification limit, the results of Qatar's produced waters analyzed do not show significant trace of halogenated acetic acids, perfluorinated compounds or BTEX biodegradation byproducts in comparison to the African's produced waters. Trace elements and radionuclides analysis are currently ongoing. Conclusions Here, we introduce innovative analytical strategies on produced water by synergic used of high resolution and multi-elemental mass spectrometry for accurate fingerprint on organic and inorganic ultra-trace contaminants study of water characteristics. Its part of an ongoing process focused on optimizing and developing analytical approaches suitable for Qatar's produced water quality prior to sustainable reuse. The methodology developed (isotopic dilution, standard addition…), is the first bimodal study of its kind. It can be used in the future to perform a non-specific screening of ultra-traces acids, metals and radionuclides compounds. The relative analytical results are being used to drive research efforts within the WSGC.

International audience; The aim of this work is to compare simultaneous isotope dilution analysis of organotin and organomercury compounds by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP/MS) on certified bivalve samples. These samples were extracted by microwave with tetramethylammonium hydroxide (TMAH). Derivatization with both NaBEt4 and NaBPr4 was evaluated, and analytical performances were compared. Two CRM materials, BCR-710 and CRM-477, were analyzed by both techniques to verify accuracy. A mixed spike containing 201Hg-enriched methylmercury (MeHg), 199Hg-enriched inorganic mercury (iHg), 119Sn-enriched monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) as well as homemade 116Sn- enriched monophenyltin (MPT), diphenyltin (DPT), and triphenyltin (TPT) was used for the isotope dilution analysis of samples. The two techniques studied were compared in terms of classic analytical parameters: linearity, precision or repeatability (i.e., percent relative standard deviation, RSD%), limit of detection (LOD), and limit of quantification (LOQ), showing excellent linearity, precision below 12 % for all analytes, and LOQs of 0.06-1.45 pg for GC-MS and 0.02-0.27 pg for GC-ICP/MS.

International audience; A method was developed for the comprehensive cartography of the selenium metabolites synthesized in the process of conversion of selenite [Se(iv)] into organic compounds and enrichment of yeast with selenium. The number of compounds detected was considerably increased (49) owing to the optimization of the fractionation procedure and the use of UPLC. The increased purity of the minor selenoorganic amino acids and oligopeptides allowed successful on-line de-novo identification based on the exact mass (

Chlamydomonas reinhardtii is a common model organism for investigation of metal stress. This green alga produces phytochelatins in the presence of metal ions. The influence of cadmium is of main interest, because it is a strong activator of phytochelatin synthase. Cell wall bound and intracellular cadmium content was determined after exposition to 70 µm CdCl(2), showing the main portion of the metal outside the cell. Nevertheless, imported cadmium was sufficient to cause significant changes in thiolpeptide metabolism and its transcriptional regulation. Modern analytical approaches enable new insights into phytochelatin (PC) distribution. A new rapid and precise UPLC-MS method allowed high-throughput PC quantification in algal samples after 1, 4, 24 and 48 h cadmium stress. Initially, canonic PCs were synthesized in C. reinhardtii during cadmium exposition, but afterwards CysPCs became the major thiolpeptides. Thus, after 48 h the concentration of the PC-isoforms CysPC(2-3) and CysGSH attained between 105 and 199 nmol g(-1) fresh weight (FW), whereas the PC(2-3) concentrations were only 15 nmol g(-1) FW. The relative quantification of γ-glutamyl transpeptidase (γ-GT) mRNA suggests the generation of CysPCs by glutamate cleavage from canonic PCs by γ-GT. Furthermore, a homology model of C. reinhardtii phytochelatin synthase was constructed to verify the use of crystal structures from Anabaena sp. phytochelatin synthase (PCS) for docking studies with canonical PCs and CysPCs. From the difference in energy scores, we hypothesize that CysPC may prevent the synthesis of canonical PCs by blocking the binding pocket. Finally, possible physiological reasons for the high abundance of CysPC compared with their canonic precursors are discussed.

cited By 11; International audience; A direct ultra-high performance reverse-phase HPLC (UHPLC) - electrospray MS/MS method was developed for the simultaneous determination of 16 fluorinated benzoic acids (FBAs) in oil reservoir waters. The separation was achieved within 5. min in a non-linear gradient mode using a 1-ml sample aliquot. The method detection limits were in the lower ng/ml range (between 0.05 and 50. ng/ml, depending on the compound) owing to the use of the travelling-wave collision cell technology. The method developed was more sensitive, faster (by avoiding sample preconcentration and purification steps) and more robust than the GC/MS methods currently used in oil industries. The accuracy of the method was verified by comparison with GC/MS results. It was applied to the determination of FBAs in water samples coming from reservoir tracing campaigns. © 2011 Elsevier B.V.

International audience; Within this study microwave assisted syntheses of functionalized polystyrene (PS), via ATRP, and tetra-aniline (TANI) end-capped polymers are demonstrated. Compared to conventional heating, microwave irradiation process in pulsed mode shows the feasibility of conducting end-capped polymers synthesis with no degradation, strong acceleration of polymerization rate and coupling reaction, controlled size and chemical formulation. Conducting polymers with controlled architectures in terms of molecular size of both the insulating (PS) and the conducting (TANI) moieties show a conductivity above 10-1 S cm-1 when containing 2 wt% TANI while composites of PS and TANI exhibited a conductivity of ca 10-5 S cm-1 when containing more than 7 wt% TANI. © 2010 Elsevier Ltd. All rights reserved.

International audience; The aim of this study was to define suitable conditions for sample handling and storage of urine samples in order to ensure reliable analysis of selenium-containing volatile metabolites. Short-term stability testing (from sample collection to 30-35 hours) included: temperature (room, i.e. 22 ± 2 °C, refrigerator (4 °C)), the presence and absence of light, and addition of a bactericide (0.05% NaN3). The long-term stability study evaluated urine storage at -20 and -80 °C over a period of 4 weeks. This work was conducted with normal urine samples, i.e. from non-supplemented human volunteers, in order to profile baseline metabolites and corresponding concentration levels. The results indicate that urine samples should be maintained in the dark immediately after collection and preferably analyzed within the day of collection. If temporary storage cannot be avoided, it should be at 4 °C after addition of NaN3. For longer period, urine samples can be stored at -20 or -80 °C without measurable changes respectively for 2 to 4 weeks. © 2011 The Royal Society of Chemistry.

cited By 4; International audience; We present the results of theoretical and experimental work on the development of new chemical passive water tracers for application in oil reservoirs. Fluorinated benzoic acids (FBAs) are currently used as chemical water tracers in oil field applications, and they were considered as "reference water tracers" in this study. The 15 newly proposed tracer molecules are halogenated derivatives of benzoic acid that are commercially available and have two halogenated substituents on the aromatic ring, either one fluorine (F) and one trifluoromethyl group (CF3) or one fluorine (F) and one chlorine (Cl). Laboratory-scale experiments were conducted to evaluate the physicochemical properties (e.g., detection, stability, and toxicity) and performance of the molecules as potential water tracers. Both the new tracers and FBAs are simultaneously detectable using the same rapid analytical tool [ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC/MS-MS)] and can therefore be used in the same tracing campaign without altering the analytical technique for the detection in reservoir water samples, which is economically desirable. Recommendations for the storage step between sampling and analysis are also discussed. © 2011 American Chemical Society.

cited By 6; International audience; A method was developed for the precise determination of selenium isotopic compositions (δ82/77Se, δ82/76Se and δ82/74Se) by hydride generation inductively coupled plasma multiple collector mass spectrometry (HG-MC ICP MS) in Se-rich yeast. The conversion of all the selenium forms into Se(iv) during digestion and reduction steps was investigated by anion-exchange ICP quadrupole MS (SAX ICP Q MS) and was found to be complete. Measurement precision values expressed as deltas (δ) with regard to NIST SRM3149 were between 0.2-0.4‰ (2SD) over a period of 6 months for 25 or 50 ng mL-1 of introduced selenium. The application of the method to the analysis of nine Se-rich yeast supplements from different manufactures showed significant variations in the isotope ratios suggesting that the latter can be an attractive parameter for the yeast provenance discrimination. © 2010 The Royal Society of Chemistry.

cited By 24; International audience; Quantitative phytochelatin (PC) analysis is, due to oxidation sensitivity of the PCs, matrix effects, and time consuming sample preparation, still a challenging analytical task. In this study, a rapid, simple, and sensitive method for precise determination of native PCs in crude extracts of the green alga Chlamydomonas reinhardtii was developed. Algae were exposed 48 h to 70 μM Cd. Coupling of ultra performance liquid chromatography and electrospray ionization tandem mass spectrometry with multi-reaction mode transitions for detection permitted the required short-time, high-resolution separation and detection specificity. Thus, under optimized chromatographic conditions, 10 thiol peptides were baseline-separated within 7 min. Relative detection limits in the nanomolar range in microliter sample volumes were achieved (corresponding to absolute detection limits at femtomol level). Next to glutathione (GSH), the most abundant cadmium-induced PCs in C. reinhardtii, namely CysGSH, PC 2, PC3, CysPC2, and CysPC3, were quantified with high reproducibility at concentrations between 15 and 198 nmol g-1 fresh weight. The biological variation of PC synthesis of nine independently grown alga cultures was determined to be on average 13.7%. [Figure not available: see fulltext.] © 2010 Springer-Verlag.

cited By 36; International audience; Normal-phase HPLC and hydrophilic interaction HPLC (HILIC) were investigated for the separation of selenometabolites in a water extract of Se-rich yeast prior to their detection by ICP-MS and identification by electrospray MS/MS. The targeted fraction was a low-abundant fraction co-eluting with salt and sulfur analogues in size-exclusion chromatography which has so far been inaccessible to Se speciation studies. The optimization of the separation conditions resulted in the highest separation efficiency when HILIC was used and elution was carried out isocratically with a low concentration ammonium acetate buffer (1 mM ammonium acetate/10 mM acetic acid) in 80% acetonitrile. Out of 15 peaks observed with the Se-specific ICP-MS detection 12 was identified by electrospray Q-TOF MS/MS (2,3-dihydroxypropionyl (DHP)-Se-methylselenocysteine [M+H]+: 272, Se-methyl-γ-glutamyl-selenocysteinylglycine dioxide [M+H]+: 402, γ-glutamyl-Se-methylselenocysteine [M+H]+: 313; isomers of γ-glutamylselenocystathionine [M+H]+: 400; Se-methyl-selenoglutathione [M+H]+: 370, isomers of N-acetylselenocystathionine [M+H]+: 313, 2,3-DHP-selenohomolanthionine [M+H]+: 373, isomers of 2,3-DHP-selenocystathionine [M+H]+: 359, 2,3-DHP-selenolanthionine [M+H]+: 345 and selenohomolanthionine [M+H]+: 285). © 2009 Elsevier B.V. All rights reserved.

cited By 59; International audience; A novel generic approach based on precolumn isotope dilution nanoHPLC-ICPMS analysis was developed for the accurate absolute quantification of sulfur-containing peptides. A 34S-labeled, species-unspecific sulfur spike (sulfate), noninteracting with analyte peptides under the optimized HPLC condition, was added directly to the chromatographic eluents. Thus a generic sulfur standard permanently present during analysis was used for peptide quantification. Interference-free detection of the 32S and 34S isotopes in ICPMS was achieved by eliminating O2 + ions in a collision cell using Xe gas at 130 μL min -1. The detection limit for sulfur was 45 μg L-1 which corresponded to 1-2 pmol of individual peptides. The method was validated by the analysis of a standard peptide solution showing high accuracy (recovery 103%) and good precision (RSD 2.1%). The combination of nanoHPLC-ICP IDMS with nanoHPLC-ESI MS/MS allowed the precise quantification and identification of sulfur-containing peptides in tryptic digests of human serum albumin and salt-induced yeast protein (SIP 18) at the picomole level. © 2007 American Chemical Society.

International audience; Various poly[3-(4-octylphenyl)thiophene]s (POPTs) were prepared either by oxidative polymerisation or by chain-growth Grignard metathesis (GRIM). In accordance with previous results, the former polymerisation yielded polydisperse POPT. The method based on the GRIM reaction made possible the preparation of medium and higher molecular weight polymers with lower polydispersities. The POPTs were found to have band-gaps of ca. 1.7 eV. The photovoltaic characteristics of POPTs-blend-[6,6]-phenyl C61 butyric acid methyl ester (PCBM) composites under AM 1.5 conditions in standard ITO/PEDOT-blend-PSS/ POPT-blend-PCBM/LiF/Al solar cells were studied. It was found that POPT prepared via GRIM could deliver greater efficiencies than its equivalent prepared by oxidative polymerisation. It is expected that access to even higher molecular weight POPTs may improve the efficiencies of such devices.

cited By 34; International audience; Speciation of heteroelement-containing proteins essential for human health is one of the most rapidly developing areas in bio-inorganic analytical chemistry (metallomics). We discuss recent advances in mass spectrometry (MS) techniques for detection and identification of selenium (Se)-containing proteins separated by gel electrophoresis (GE). These advances include location of Se-containing bands in 1D GE or spots in 2D GE by laser-ablation inductively coupled plasma MS (LA-ICP-MS) followed by protein identification by matrix-assisted laser-desorption/ionization MS (MALDI-MS) and nano-high-performance liquid chromatography-electrospray-tandem MS (nanoHPLC-ESI-MS2). We highlight the differences with the classical proteomics approach resulting from the presence of the Se atom. © 2007 Elsevier Ltd. All rights reserved.

International audience; A three-step chromatographic procedure using orthogonal separation mechanisms (size-exclusion, cation-exchange and ion-pairing reversed phase) was developed to purify three low molecular weight selenospecies, including the major compound, from the aqueous extract of monkeypot (Lecythis minor) nuts. The following reversed-phase nanoHPLC-electrospray Q-TOF-MS/MS allowed the formal standardless identification of selenocystathionine and two isoforms of γ-glutamyl-selenocystathionine. This is the first MS and MS/MS-based formal evidence of the presence of these compounds in a biological sample.

cited By 41; International audience; ICP collision cell MS was optimized for the detection and retention-time marking of selenium-containing peptides in nanoHPLC (75 μm column) after on-line 100-fold preconcentration on a capillary (300 μm id) precolumn. The mobile phase composition, gradient and flow rate were chosen to allow electrospray-MS/MS to be successfully run in parallel in identical separation and preconcentration conditions in order to produce two matching sets of chromatograms: an element-specific one and a molecule-specific one. Knowledge of the retention time of a Se-containing peptide of interest allowed efficient data mining in the corresponding ES-MS chromatogram and the identification of minor Se-species. A third chromatogram was run to obtain collision-induced dissociation data for the target peptides. The performance of the method was demonstrated for a comprehensive on-line characterization of a mixture of peptides in a tryptic digest of a Se-containing protein fraction isolated by size-exclusion chromatography from a selenium yeast extract. The method allowed the identification of whole series of Se/S substitutions in individual peptides and, in some cases, sequencing of isomers differing in the position of selenomethionine residues in the amino acid sequence. © The Royal Society of Chemistry 2006.

cited By 19; International audience; In this work, the simultaneous determination of four organometallic species (monomethylmercury, monobutyltin, dibutyltin and tributyltin) in environmental samples by using a GC-MS system with electron ionisation has been established. The measurement of isotope ratios in each species was accomplished by selecting the most adequate molecular cluster, and simple mathematical equations were applied to correct the contributions of 13C from the organic groups attached to the tin and mercury atoms. The influence of different parameters such as dwell time on the precision and accuracy of the measured isotope ratios in each target species has also been studied. The determination and the sample preparation procedures presented in this work were first individually validated by analysing several certified reference materials for butyltin compounds (mussel tissue CRM-477 and marine sediment SOPH-1) and for monomethylmercury (tuna fish CRM-464) using an innovative focused microwave technology for the extraction of the species from the solid samples. Additionally, the simultaneous determination of the four species was successfully validated by obtaining quantitative recoveries in spiked natural waters and by analysing the certified reference material BCR-710 (certified in tributyltin and monomethylmercury). The values obtained in such certified tissue were fully in agreement not only with the certified mass fractions but also with the proposed indicative values for mono- and dibutyltin.

cited By 12; International audience; Chlorobenzene cast films of poly(3-hexylthiophene)-Wend-[6,6]-phenyl C 61 butyric acid methyl ester (P3HT-blend-PCBM) in 1:1 ratios were used in photovoltaic cells with the structure glass/ITO/PEDOT-Wend-PSS/P3HT- Wend-PCBM/LiF/Al. By varying the molecular weights of the PSHTs from 4500 to 280000 g mol-1, it was found that P3HT molecular weight distributions had an important impact on cell characteristics and the most effective annealing temperature required.

cited By 158; International audience; A series of poly(3-hexylthiophene)s (P3HTs) and poly(3-butylthiophene)s (P3BTs) with predetermined molecular weights and varying polydispersities are prepared using a simplified Grignard metathesis chain-growth polymerization. Techniques were elaborated to prepare extremely high molecular weight P3HT (number-average molecular weight of around 280000 g mol-1) with a low polydispersity (< 1.1) without resorting to fractionation. Optimization of the annealing of a series of solar cells based on blends of poly(3- alkylthiophene)s (PSATs) and [6,6]-phenyl C61 butyric acid methyl ester indicates that the polydispersities, molecular weights, and degrees of conjugation of the P3ATs all have an important impact not only on cell characteristics but also on the most effective annealing temperature required. The results indicate that each cell requires annealing treatments specific to the type of polymer and its molecular weight distribution. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.

International audience; An analytical methodology based on high-resolution high mass accuracy electrospray ionization (ESI) tandem MS assisted by Se-specific detection using inductively coupled plasma mass spectrometry (ICP MS) was developed for speciation of selenium (Se) in seeds of black mustard (Brassica nigra) grown on Se-rich soil. Size-exclusion LC-ICP MS allowed the determination of the Se distribution according to the molecular mass and the control of the species stability during extraction. The optimization of hydrophilic interaction of LC and cation-exchange HPLC resulted in analytical conditions making it possible to detect and characterize over 30 Se species using ESI MS, including a number of minor (\textless0.5%) metabolites. Selenoglucosinolates were found to be the most important class of species accounting for at least 15% of the total Se present and over 50% of all the metabolites. They were found particularly unstable during aqueous extraction leading to the loss of Se by volatilization as methylselenonitriles and methylselenoisothiocyanates identified using gas chromatography (GC) with the parallel ICP MS and atmospheric pressure chemical ionization (APCI) MS/MS detection. However, selenoglucosinolates could be efficiently recovered by extraction with 70% methanol. Other classes of identified species included selenoamino acids, selenosugars, selenosinapine and selenourea derivatives. The three types of reactions leading to the formation of selenometabolites were: the Se-S substitution in the metabolic pathway, oxidative reactions of -SeH groups with endogenous biomolecules, and chemical reactions, e.g., esterification, of Se-containing molecules and other biomolecules through functional groups not involving Se.