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Pau, France

Vacchina V.,UT2A | Oguey S.,Pancosma | Ionescu C.,Pancosma | Bravo D.,Pancosma | Lobinski R.,LCABIE UMR5254
Analytical and Bioanalytical Chemistry

A method was developed for the determination of metal complexes with glycine (glycinates, [M(Gly)x(H2O)y(SO 4)z]n, where M denotes Zn, Cu, Mn and Fe) in premix samples used for the preparation of animal feeds enriched in essential trace elements. The method was based on the extraction of the glycinates with 10 mM ammonium acetate (pH 7.4) followed by their determination using capillary electrophoresis with ICP MS detection. The stability of the glycinates in solution was verified by electrospray TOF-MS. Each supplement was shown to be a mixture of complexes, with polymerization degrees ranging from n∈=∈1 to n∈=∈4 (depending on the metal), that were fully or partially dehydrated. The metal glycine complex moiety was found to be preserved during capillary electrophoresis. The detection limits, calculated as three times the standard deviation of the blank plus the blank, were between 0.05 and 0.2 μg mL-1 (as the metal), and the calibration curves were linear, allowing the analysis of premix samples. Repeatability for glycinate standards was below 12%, and analytical precision was typically within 15%. © 2010 Springer-Verlag. Source

A method was developed for the quantification of Zn-, Cu- and Mn-glycinates in supplemented feed samples. The coupling of capillary electrophoresis (CE) with ICP MS detection after purification of the extract by ultrafiltration was shown to be efficient for the quantitative recovery of glycinates. The method developed was then applied to evaluate the bioaccessibility of glycinates using a sequential enzymolysis approach. The data obtained indicated a strong bioaccessibility of each element (79-94%). A new complex was also found to be formed during the digestion process. Bioavailability was then evaluated by analyzing plasma samples of horses supplemented with glycinates-rich feed. Intact glycinates could not be detected in plasma samples but a Cu-containing molecule was found more abundant after CuGly treatment. © 2013 Elsevier B.V. Source

Mamindy-Pajany Y.,University of Nice Sophia Antipolis | Bataillard P.,Bureau de Recherches Geologiques et Minieres | Seby F.,UT2A | Crouzet C.,Bureau de Recherches Geologiques et Minieres | And 5 more authors.
Soil and Sediment Contamination

Arsenic speciation was determined in marina sediments of the French Mediterranean coast. The sediment from L′Estaque marina was highly impacted by both metallurgical activities and by the commercial port of Marseille, in contrast to the sediment from St. Mandrier marina that was less polluted. In the solid phases, As(III) was the dominant species in the L′Estaque sediment, whereas As(V) was the main form in the St. Mandrier sediment, with total As concentrations in the range 160-350 mg/kg and 17-20 mg/kg, respectively. In both sites, arsenic was the major trace element detected in interstitial water, its concentration reaching values higher than 1 mg/L in the L′Estaque sediment. Sulfate-reduction seemed to be more active in the L′Estaque site, probably because of the availability of easily biodegradable organic matter. This condition favored the formation of thioarsenates that were quantified here for the first time in a polluted marine sediment. Thioarsenates represented 69 ± 24% of total dissolved As in the 15-60 cm depth sediment layer. Our results suggest that bacterial activity may significantly contribute to increased arsenic solubility and mobility in harbor sediments, where crude oil input stimulates sulfate-reducers. © 2013 Copyright Taylor and Francis Group, LLC. Source

Vacchina V.,UT2A | Moutet M.,Tetrahedron | Yadan J.-C.,Tetrahedron | de Baene F.,Eco Solution | And 2 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences

An analytical method was developed for the simultaneous speciation of selenomethionine (SeMet) and 2-hydroxy-4-methylselenobutanoic acid (NutraSelen®), a new SeMet precursor. The compounds could be baseline resolved by ion-pairing reversed-phase HPLC using ICP MS detection. Detection limits of 1 ng mL-1 (Se content) could be reached. SELM-1 reference material was used to validate the SeMet measurement. Additionally, the quantification of NutraSelen® was validated by standard addition together with checking the Se mass balance. The procedure developed was then applied to the monitoring of the conversion of NutraSelen® into SeMet by yeast. © 2010 Elsevier B.V. All rights reserved. Source

It is now recognized that measurement of the total concentration of an element is not sufficient to obtain information about its environmental impact and its toxicity, elements being present under different chemical forms or as nanoparticles (NPs). Only size fractionation techniques or speciation analysis (identification and determination of the different species of an element) yield this information. This approach needs to have well defined sampling, storage and sample treatment procedures that do not modify the distribution of the chemical forms. Furthermore, taking into account the new EU regulations, this approach also needs more and more sensitive, accurate and robust analytical tools. Hyphenation between separation techniques based on liquid or gas chromatography or flow fractionation on one hand and inductively coupled plasma mass spectrometry (ICP MS) on the other hand are analytical methods that present the greatest potential for these analyses. An overview of these approaches is detailed in terms of their potential and their analytical performances as well as applications for different elements (As, Hg, Sn, Cr or Sb). Through these examples, the following items will be described: • The main validation tools such as species isotopic dilution (methylmercury in natural waters) and the use of alternative methods (example of Sb speciation); • Preconcentration techniques to decrease quantification limits to be in agreement with new regulations (Cr(VI)); • The physico-chemical characterization of colloïds in natural waters. © 2015, Institut National de la Research Scientifique. All rights reserved. Source

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