Specificity and origin of the stability of the sr isotopic ratio in champagne wines

The 87Sr/86Sr ratio of 39 Champagnes from six different brands, originating from the whole “Appellation d’Origine Contrôlée” (AOC) Champagne was analyzed to establish a possible relation with the geographical origin. Musts (i.e., grape juice) and base wines were also analyzed to study the evolution of the Sr isotopic ratio during the elaboration process of sparkling wine. The results demonstrate that there is a very homogeneous Sr isotopic ratio (87 Sr/86 Sr = 0.70812, n = 37) and a narrow span of variability (2? = 0.00007, n = 37). Moreover, the Sr concentrations in Champagnes have also low variability, which can be in part explained by the homogeneity of the bedrock in the AOC Champagne. Measurements of the87 Sr/86 Sr ratio from musts and base wines show that blending during Champagne production plays a major role in the limited variability observed. Further, the87 Sr/86 Sr of the musts were closely linked to the87 Sr/86 Sr ratio of the vineyard soil. It appears that the87 Sr/86 Sr of the product does not change during the elaboration process, but its variability decreases throughout the process due to blending. Both the homogeneity of the soil composition in the Champagne AOC and the blending process during the wine making process with several blending steps at different stages account for the unique and stable Sr isotopic signature of the Champagne wines.Centre de Spectrometrie de Masse pour les Sciences de la Réactivité et de Spéciatio

Inorganic Mass Spectrometry

To establish a method for sensitive, accurate, and precise determination of Se in real samples, isotope dilution analysis using high-power nitrogen microwave-induced plasma mass spectrometry (N 2 MIP-IDMS) was conducted. In this study, freeze-dried human blood serum (Standard Reference Material, NIES No. 4) provided by NIES (National Institute for Environmental Studies) was used as a real sample. The measured isotopes of Se were 78 Se and 80 Se which are the major isotopes of Se. The appropriate amount of a Se spike solution was theoretically calculated by using an error multiplication factor (F) and was confirmed experimentally for the isotope dilution analysis. The mass discrimination effect was corrected for by using a standard Se solution for the measurement of Se isotope ratios in the spiked sample. However, the sensitivity for the detection of Se was not so good and the precision of the determination was not improved (2-3%) by N 2 MIP-IDMS with use of the conventional nebulizer. Therefore, a hydride generation system was connected to N 2 MIP-IDMS as a sample introduction system (HG-N 2 MIP-IDMS) in order to establish a more sensitive detection and a more precise determination of Se. A detection limit (3σ) of 10 pg mL -1 could be achieved, and the RSD was less than 1% at the concentration level of 5.0-10.0 ng mL -1 by HG-N 2 MIP-IDMS. The analytical results were found to be in a good agreement with those obtained by the standard addition method using conventional Ar ICPMS. It is well-known that Se is an essential element for all mammals. Se deficiency leads to deficiency syndromes, for example, Keshan disease, which is known for cardiac insufficiency that occurred in children and pregnant women in China. Problems also occur if the concentration of Se is too high; for example, gastroenteric disorders, dermatitis, and neurotic disorders are caused by excessive intake of Se. Moreover, it is well-known that the range of permissive intake amounts of Se is very narrow for human beings. Therefore, it is restricted as a toxic element in environmental standards. There are several sources of environmental Se pollution: the processes of Se refinement and the production processes of Se-containing products. For these reasons, the accurate and precise determination of trace levels of Se in environmental and biological samples is required, and studies of Se determination have been reported by several groups. [1][2][3][4][5][6][7][8][9][10][11] Because Ar ICPMS can measure multiple elements at a concentration range from ng mL -1 to fg mL -1 , it has widespread use in the determination of trace elements in various samples. 12-25 However

Arsenic speciation in shrimp and mussel from the Mid-Atlantic hydrothermal vents

cited By 52International audienceSpecimens of shrimp (Rimicaris exoculata) and mussel (Bathymodiolus puteoserpentis) were collected 3500 m below the ocean surface at the hydrothermal vents of the mid-Atlantic Ridge (TAG and Snake Pit sites, respectively). Arsenic, a potentially toxic element, is among the substances emitted by the hydrothermal vents. The hydrothermal vent shrimp, which are known to be a primary consumer of the primary producing chemolithoautotrophic bacteria, contained arsenic at 13 μg g-1 almost exclusively as arsenobetaine (AsB). Arsenic was present in the soft tissues of the mussel at 40 μg g-1 and the major part of the extractable arsenic species in the adductor muscle/mantle tissues and in the gill were present as dimethylarsinylriboside-derivatives (arsenosugars), while AsB was present at 16 and 3.6%, respectively, in these tissues. In spite of the absence of biosynthetically active algae, the pattern of arsenic species found in the shrimp and mussel species in the deep-sea is similar to that found in their counterparts from the ocean surface. It is concluded that the autotrophic bacteria of the hydrothermal vent ecosystem and the symbiotic bacteria harboured in the mussel species are responsible for the biosynthesis of the organoarsenicals detected in the two hydrothermal vent animal species. It is not known if the formation of the same organoarsenicals in the surface and deep sea ecosystems is primarily a detoxification process of inorganic arsenic, or whether these compounds play a physiological role

Rapid fingerprinting of 239Pu and 240Pu in environmental samples with high U levels using on-line ion chromatography coupled with high-sensitivity quadrupole ICP-MS detection

A simple, rapid on-line analytical method for the determination of plutonium (Pu) isotopes in soil and sediment samples was developed. Microwave leaching was used to extract Pu from the major sample matrix. L-ascorbic acid was found to be the most appropriate agent to convert all the Pu to Pu(IV) for chromatography. Flow injection chromatography using TEVA resin was optimized to separate, preconcentrate and elute Pu from other constituents of the sample including 238U. An APEX desolvation unit with a PEEK Mira Mist nebulizer was used to minimize clogging and hydride interferences. The advantage of using a high sensitivity quadrupole ICP-MS instrument for Pu detection was demonstrated. The detection limit was found to be 3 and 0.3 pg kg-1 for 239Pu and other Pu isotopes, respectively, while for 239+240Pu it was 10 mBq kg-1. To demonstrate the applicability of the method, Pu activities and atom ratios were measured for different sediments from the northern Asian region

Bacterial community structure along the Adour estuary (French Atlantic coast): influence of salinity gradient versus metal contamination

Salinity, other physico-chemical parameters and anthropogenic pollution are the main factors affecting bacterial communities in estuaries. We estimated the impact of these parameters on the distribution of bacterial communities in the Adour estuary (France), a moderately Polluted water body characterized by short residence times of particles and water and absence of a maximum turbidity zone. Eight stations were established along the salinity gradient from freshwater to marine conditions. For the 3 typical estuarine stations (water mixing zone), samples were collected at both low and high tide and at different depths according to the position of the halocline. This sampling strategy generated 35 samples with different degrees of mixing between fresh water and seawater. All the samples were characterized by their physico-chemical parameters and trace metal contents (as a contamination tracer). The structure of bacterial communities was determined by T-RFLP fingerprinting. The metal-salinity profiles suggested dilution processes and/or usual geochemical reactivity for the elements sensitive to sorption/desorption mechanisms (Cd, Mn). Metal concentrations were low, with no evidence of contaminated plumes, suggesting that metal concentrations were not influencing bacterial diversity. A well-established estuarine bacterial community was observed, comprising mostly Cyanobacteria, Planctomyces and Alphaproteobacteria. This community was different from fresh and seawater communities, and a shift in community composition was observed between 10 and 34 PSU. Although residence time in the Adour estuary is very short, the salinity and halocline in this water body are likely to be the main parameters influencing bacterial community composition