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International audience; A complementary approach using Liquid Chromatographic-Mass Spectrometric analysis was proposed to characterize phenolic compounds from the methanol-water extracts of K. ivorensis A. Chev. Two High Performance Liquid Chromatography (HPLC) complementary methods were used for the determination of phenolic compounds from the bark, sapwood and heartwood of K. ivorensis. Methods employed involved direct analysis after filtration at 0.20 µm, using a RP C18 column and UV-VIS/ESI-FTMS detection. The methods used were different by their elution gradient and allowed analyzing the chemical composition of three parts of African mahogany extracts. In this study, 22 phenolic compounds and derivatives from K. ivorensis were separated, determined or tentatively characterized for the first time based on their methanol/water/formic acid extract mass spectra. The difference of gradients eluted various compounds, 8 were obtained with the first method and 14 with the second one. The main products were hydroxybenzoic acid and derivatives, resorcinol, esterified compounds, mannitol, quercetin and derivatives, dihydroxyflavan, and trihydroxyflavan.

In relation to the decrease of selenium (Se) content in aquafeeds, the impact of level and form of parental and dietary Se supplementation was investigated in rainbow trout fry using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP MS) bioimaging. The offspring of rainbow trout broodstock, fed either a control diet without any Se supplementation (0.3 mg Se/kg diet) or a diet supplemented with Se (0.6 mg Se/kg diet) either as sodium selenite or hydroxy-selenomethionine, were sampled at swim-up fry stage or after 11 weeks of cross-feeding. Total body Se levels were influenced by parental Se nutrition in swim-up fry and by direct Se feeding in 11-week fry with higher levels in the Se-supplemented groups compared with the control and the highest levels in the hydroxy-selenomethionine treatment. The Se retention was lower for dietary sodium selenite. Selenomethionine levels increased when Se was provided as hydroxy-selenomethionine. LA-ICP MS maps revealed yolk in swim-up fry and intestine, liver, and kidney in 11-week fed fry as tissues with high Se abundance. In swim-up fry, muscle Se was the highest abundant when parents were fed hydroxy-selenomethionine. In 11-week fed fry, muscle Se abundance was higher in the head part of fry fed both Se-supplemented diets, but only in the tail part of fry fed hydroxy-selenomethionine. Liver Se abundance was higher in fry fed sodium selenite compared with the control diet supporting the hypothesis that tissue Se distribution can be influenced by parental and dietary Se forms and levels.

International audience; Quantitative localization of metals in biological tissue sections is critical to obtain insight into metal toxicity mechanisms or their beneficial characteristics. This study presents the development of a quantitative LA-ICP MS bioimaging methodology based on the polymer film strategy and internal standardization. To maximize the number of elements mapped, an aqueous soluble polymer (dextran) was selected. Among the elements studied, the great majority (eight out eleven), i.e., Co, Ni, Cu, Zn, Se, Mo, Cd and Pt, exhibited linear regression after LA-ICP MS analysis of metal-spiked polymer standards. Methodology performances were carefully assessed as a function of the three internal standards (In, Rh and Ir) considered, the analytical operational conditions (ICP power, addition of O 2 to ICP, and laser fluency) and the thickness of the biological tissue section. The results indicated that three groups (Co, Mo; Ni, Cu, Pt; and Zn, Se, Cd) of elements could be distinguished from their analytical response as a function of analytical conditions and the internal standard. These different element behaviors appeared to be mainly First Ionization Potential dependent (FIP). For elements with lower FIP (Co, Ni, Cu, Mo and Pt), differential responses due to carbon load in the ICP MS plasma could be efficiently corrected as a function of analytical conditions. Matrix effects were more pronounced for higher FIP elements (i.e., Zn, Cd and Se), and analysis of

International audience; In the search for an alternative strategy to the radioactivity measurement conventionally performed to probe receptor–ligand interactions in pharmacological assays, we demonstrated that selenium labeling of the studied ligand combined with elemental mass spectrometry was as efficient and robust as the reference method but devoid of its environmental and health hazards. The proof-of-concept was illustrated on two GPCR receptors, vasopressin (V1A) and cholecystokinin B (CCK-B), involving peptides as endogenous ligands. We proposed several methodologies to produce selenium-labeled ligands according to peptide sequences along with binding affinity constraints. A selection of selenopeptides that kept high affinities toward the targeted receptor were engaged in saturation and competitive binding experiments with subsequent sensitive RP-LC-ICP-MS measurements. Experimental values of affinity constant (Ki) were perfectly correlated to literature data, illustrating the general great potency of replacing radioactive iodine by selenium for ligand labeling to further undergo unaffected pharmacology experiments efficiently monitored by elemental mass spectrometry.

International audience; A HPLC double reaction monitoring MS/MS method was developed for the determination of a wide range (>20) of sulphonamide residues in several edible animal (sheep, pork, beef, chicken and dromedary) tissues. Sample preparation was based on the simultaneous extraction into acetonitrile solution followed by a clean-up using primary secondary amine beads. Quantification was carried out using matrix-matched calibration curves. The limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.5 to 14.5 μg kg-1 and from 1.8 to 48.4 μg kg-1, respectively. The decision limit (CCα) and decision capability (CCβ) obtained were below 100 μg kg-1 for sulphonamides and below 5 μg kg-1 for dapsone. The method was validated in terms of recoveries and inter- and intra-day precision by reference analyses of meat samples using LC-Orbitrap MS and by the analysis of a reference material. The method was applied to the analysis of several animal tissue samples collected in Lebanon. The highest values were observed for sulfamethazine and sulfadimethoxine at 70.2 and 62.5 μg kg-1 in sheep tissues.

International audience; A coupling of thin layer chromatography with laser ablation ICP SF MS was developed for the fractionation of Ni, V, Fe and S in crude oil and its fractions (saturate, aromatic, resin and asphaltene). The detection limits were 18 ng g -1 and 23 ng g -1 for nickel and vanadium, respectively, and a sample could be characterized in terms of the metal distribution as a function of species polarity within 10 min. The method was used to characterize the metal distribution in crude oils of different origins and their different fractions. © 2012 Elsevier B.V. All rights reserved.

cited By 0; International audience; Chloride is often considered as the main chlorine form in soils. However, recent studies show that chlorine is mostly present in soils as naturally produced organically bound molecules. The relative contribution of biotic, including microbial, and abiotic processes to formation of organically bound chlorine remains poorly understood. We performed a37Cl spiking batch experiment with a forest soil incubated under abiotic and biotic conditions over two time periods to simultaneously monitor the formation of organically bound chlorine from natural and tracer chlorine. To compare biotic and abiotic conditions without biased effect of sterilization technique for abiotic control, the soil was irradiated and reinoculated or not with soil microflora. Fifteen days after microbial inoculation, the natural non-extractable organic chlorine content in the inoculated soil was significantly higher than in the sterile soil, showing that microbial activity contributed to formation of organically bound chlorine. However, no significant difference was noted between the two incubation periods. The same trend was noted for tracer chlorine, yet without a significant difference. The present study shows that chlorination is mediated by microbial activity, but there is also some indication of abiotic formation of organically bound chlorine, with a non-extractable organic tracer chlorine formation of about 6% just after spiking in abiotic conditions. © 2016 Elsevier Ltd

International audience; Due to their toxicity, persistence, and bioaccumulation, metals are important marine environment pollutants, especially in low renewal rate water such as the Mediterranean Sea, receiving a lot of untreated industrial waste. The impact of a phosphate fertilizer plant on the marine biota metal contamination was studied. Several types of organisms: crabs, mussels, patella and fish were collected from two areas of the Lebanese coast, one subjected to the impact of the plant and another away from it; samples were analyzed for Zn, U, Cr, V, Mn, Ni, Co, Cu, As, Cd and Pb by ICP-MS. Higher accumulation was in crabs, patella, and mussels. Fish accumulated principally Zn, Cu, and Cd; a difference was observed between species and tissues. Cytosol metal fractionation using size-exclusion LC-ICP-MS showed principally Pb, As, Co, and Mn in the low molecular weight fraction (\textless1.8 Da); Cd, Zn, and Cu in the metallothionein fraction (1.8–-18 k Da), and Ni in high molecular weight fraction (\textgreater20 kDa).

International audience; The size distribution of sulfur, vanadium, and nickel was determined for four crude oils and their distillation cuts using gel permeation chromatography (GPC) coupled to inductively coupled plasma high-resolution mass spectrometry (ICP HR MS). The results show a trimodal distribution of vanadium and nickel compounds in the crude oils, the atmospheric residues, and the vacuum residues and, for sulfur compounds, either a mono- or bimodal distribution depending upon the distillation cut considered. A correlation exists between the sulfur fraction retention times and the temperature cuts of the distillation for a temperature below 560 degrees C and also between the viscosity of the crude oils and the proportion of trapped sulfur compounds in a higher boiling temperature fraction. The thermic treatment applied for the distillation increases the aggregation of low- and medium-molecular-weight compounds of vanadium and nickel into higher molecular weight aggregates between the crude oil on the one hand and the atmospheric residue and vacuum residue on the other hand, especially when the crude oil has a high total sulfur content.

International audience; A new high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) method was developed for a simultaneous multi-residue analysis of 22 sulfonamides (SAs) and their metabolites in edible animal (pig, beef, sheep and chicken) tissues. Sample preparation was optimized on the basis of the "QuEChERS" protocol. The analytes were identified using their LC retention times and accurate mass; the identification was further confirmed by multi-stage high mass accuracy (

International audience; In the search of new robust and environmental-friendly analytical methods able to answer quantitative issues in pharmacology, we explore liquid chromatography (LC) associated with elemental mass spectrometry (ICP-MS) to monitor peptides in such complex biological matrices. The novelty is to use mass spectrometry to replace radiolabelling and radioactivity measurements, which represent up-to now the gold standard to measure organic compound concentrations in life science. As a proof of concept, we choose the vasopressin (AVP)/V1A receptor system for model pharmacological assays. The capacity of ICP-MS to provide highly sensitive quantitation of metallic and hetero elements, whatever the sample medium, prompted us to investigate this technique in combination with appropriate labelling of the peptide of interest. Selenium, that is scarcely present in biological media, was selected as a good compromise between ICP-MS response, covalent tagging ability using conventional sulfur chemistry and peptide detection specificity. Applying selenium monitoring by elemental mass spectrometry in pharmacology is challenging due to the very high salt content and organic material complexity of the samples that produces polyatomic aggregates and thus potentially mass interferences with selenium detection. Hyphenation with a chromatographic separation was found compulsory. Noteworthy, we aimed to develop a straightforward quantitative protocol that can be performed in any laboratory equipped with a standard macrobore LC-ICP-MS system, in order to avoid time-consuming sample treatment or special implementation of instrumental set-up, while allowing efficient suppression of all mass interferences to reach the targeted sensitivity. Significantly, a quantification limit of 57 ng Se L-1 (72 femtomoles of injected Se) was achieved, the samples issued from the pharmacological assays being directly introduced into the LC-ICP-MS system. The established method was successfully validated and applied to the measurement of the vasopressin ligand affinity for its V1A receptor through the determination of the dissociation constant (Kd) which was compared to the one recorded with conventional radioactivity assays.

International audience; A novel method for the preparation of crude oil samples based on a xerogel matrix was developed for elemental analysis using laser ablation-double focusing sector field inductively coupled plasma-mass spectrometry. The samples and aqueous solution were successfully encapsulated using zirconium n-propoxide. The use of xerogel produces stable and homogeneous pellets, avoids splashing of the sample and allows the use of aqueous inorganic standards to elaborate the calibration curve. Sulfur, nickel and vanadium were selected as test elements and indium was used as the internal standard to correct the variations in the amount of material ablated. The correlation coefficients of the calibration curves for all the elements tested were better than 0.990 except for sulfur. Crude oil results showed no significant statistical differences between the sol-gel results and those obtained with similar studies. © 2012 The Royal Society of Chemistry.

International audience; A novel multiresidue method was developed for the simultaneous analysis of 34 organochlorines, including chlorobenzenes, chlorophenols, chlorinated hydrocarbons and chlorinated olefins, in soil by GC-MS, using a QuEChERS-based extraction. The conventional QuEChERS method was optimised and, for the first time, the use of a non miscible-water solvent was required. The method was compared to ASE extraction, versatile technique widely used for the soils' extraction and QuEChERS-based method was shown to be the most efficient in terms of recoveries, simplicity and rapidity. For ASE, recoveries between 42% and 85% were obtained for the majority of the compounds. However, due to the high pressure, all volatile compounds were lost. In opposite, QuEChERS extraction allowed detection and quantification of all the compounds with recoveries between 60% and 100%. Moreover, no additional clean up by dispersive SPE on PSA was necessary, which allowed reducing the cost of the analysis. Performance of the method was assessed. The method was linear over the range of concentration of 10-5000 μg kg−1. Precision, expressed as intra-day precision and inter-day variation was verified at three concentrations. Limits of detection were from 2 to 50 μg kg−1 and limits of quantification from 7 to 170 μg kg−1 for the majority of the compounds (chlorobenzenes and chlorinated hydrocarbons and olefins), except for chlorophenols. The method was further applied to different soils coming from a contaminated industrial site, where a new environmental remediation process, using phytoremediation, was tested. The results showed that the method could be applied to any kind of soils (mineral or organic) and was appropriate to very volatile compounds which were not available with conventional technique.

International audience; One of the factors that may explain nowadays honeybees' colonies losses is the increasing presence of chemicals in the environment. The aim of this study is to obtain a global view of the presence of environmental contaminants in beehives and, develop a fast, cheap and sensitive tool to analyze environmental contaminants in apiarian matrices. A multi residue analysis was developed to quantify 80 environmental contaminants, pesticides and veterinary drugs, belonging to different chemical classes, in honeys, honeybees and pollens. It consists in a single extraction, based on a modified "QuEChERS method", followed by gas chromatography coupled with Time of Flight mass spectrometry (GC-ToF) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The "QuEChERS method" combines salting-out liquid-liquid extraction with acetonitrile and a dispersive-SPE clean up. It was adjusted to honey and especially to honeybee and pollen, by adding a small fraction of hexane in acetonitrile to eliminate lipids that interfere with mass spectrometry analysis. This method, combined with accurate and sensitive detection, allowed quantification and confirmation at levels as low as 10 ng/g, with recoveries between 60 and 120%. Application to more than 100 samples of each matrix was achieved for a global view of pesticide presence in the honeybee environment. Relatively high percentages of honeys, honeybees and pollens were found to be contaminated by pesticides used to combat varroa but also by fungicides like carbendazim and ubiquitous contaminants.

International audience; A multi residue analysis was developed for screening, quantification and confirmation of 36 priority organic compounds included in the 2000/60/EC European Water Framework Directive. The compounds analyzed included 19 pesticides, 8 PAH, 5 endocrine-disruptors and 4 organochlorine compounds. The method was developed in three steps. First, automated off-line solid-phase extraction using Strata X cartridges was optimized to trap simultaneously the 36 studied compounds. Second, the more volatile compounds were analysed by gas chromatography coupled to mass spectrometry with electron impact ionisation in selected ion monitoring mode (SIM). Third, the last 20 compounds were detected and quantified, in one run, by liquid chromatography coupled to fluorescence detector and tandem mass spectrometry. The excellent selectivity and sensitivity allowed us satisfactory quantification and confirmation at levels as low as 0.2-67 ng L(-1) with recoveries between 59 and 105%. Such methodology was then applied to French surface waters: all the waters present organic contaminants, and their concentration varied according to the origin and nature of substances.

International audience; A Se-targeted bottom-up proteomics approach was developed for the identification of Se-containing proteins in rice grown naturally on seleniferous soils. The proteins were separated by 2D gel electrophoresis. The position of Se-containing spots was tentatively identified by the correlation between the 1D isoelectrofocusing (IEF) and 1D SDS electropherograms of a sample aliquot and confirmed by 78Se imaging in the 2D gel. The method was complemented by the ICP-MS assisted shotgun proteomics approach. The proteins were identified by capHPLC with the dual ICP MS and electrospray Orbitrap MS detection. The first ever comprehensive study of rice selenoproteome revealed the presence of selenium, as both selenomethionine (SeMet) and selenocysteine (SeCys) residues, in a dozen proteins including a 19 kDa globulin, granule-bound starch synthase, and the family of glutelin-type seed storage proteins.