WorldWideScience

Sample records for hydrogen isotopic ratios

  1. Insights into Wilson's Warbler migration from analyses of hydrogen stable-isotope ratios

    Science.gov (United States)

    Jeffrey F. Kelly; Viorel Atudorei; Zachary D. Sharp; Deborah M. Finch

    2002-01-01

    Our ability to link the breeding locations of individual passerines to migration stopover sites and wintering locations is limited. Stable isotopes of hydrogen contained in bird feathers have recently shown potential in this regard. We measured hydrogen stable-isotope ratios (deltaD) of feathers from breeding, migrating, and wintering Wilson's Warblers. Analyses...

  2. Stable isotope ratio measurements in hydrogen, nitrogen, and oxygen using Raman scattering

    International Nuclear Information System (INIS)

    Harney, R.C.; Bloom, S.D.; Milanovich, F.P.

    1975-01-01

    A method for measuring stable isotope ratios using laser Raman scattering was developed which may prove of significant utility and benefit in stable isotope tracer studies. Crude isotope ratio measurements obtained with a low-power laser indicate that with current technology it should be possible to construct an isotope ratio measurement system using laser Raman scattering that is capable of performing 0.1 percent accuracy isotope ratio measurements of 16 O/ 18 O in natural abundance oxygen gas or 14 N/ 15 N in natural abundance nitrogen gas in times less than two minutes per sample. Theory pertinent to the technique, designs of specific isotope ratio spectrometer systems, and data relating to isotope ratio measurements in hydrogen, nitrogen, and oxygen are presented. In addition, the current status of several studies utilizing this technique is discussed. (auth)

  3. Hydrogen isotope ratios of mouse tissues are influenced by a variety of factors other than diet

    International Nuclear Information System (INIS)

    DeNiro, M.J.; Epstein, S.

    1981-01-01

    Hydrogen isotopes are fractionated during biochemical reactions in a variety of organisms. A number of experiments have shown that the D/H ratios of animals and their tissues are not controlled solely by the D/H ratios of their food. The authors performed a simple experiment which indicated that the D/H ratios of a significant fraction of the organically bonded hydrogen in animal tissues must be determined by the isotopic composition of water that the samples encounter. Aliquots of dried mouse brain and liver and mouse food were exposed to water vapors of different D/H ratios prior to isotopic analysis. The results of the experiment showed that at least 16 percent of the hydrogen in mouse brain is exchangeable with the hydrogen of water; the corresponding values for mouse liver and mouse food were 25 to 29 percent

  4. Stable oxygen and hydrogen isotopes of brines - comparing isotope ratio mass spectrometry and isotope ratio infrared spectroscopy

    Science.gov (United States)

    Ahrens, Christian; Koeniger, Paul; van Geldern, Robert; Stadler, Susanne

    2013-04-01

    Today's standard analytical methods for high precision stable isotope analysis of fluids are gas-water equilibration and high temperature pyrolysis coupled to isotope ratio mass spectrometers (IRMS). In recent years, relatively new laser-based analytical instruments entered the market that are said to allow high isotope precision data on nearly every media. This optical technique is referred to as isotope ratio infrared spectroscopy (IRIS). The objective of this study is to evaluate the capability of this new instrument type for highly saline solutions and a comparison of the analytical results with traditional IRMS analysis. It has been shown for the equilibration method that the presence of salts influences the measured isotope values depending on the salt concentration (see Lécuyer et al, 2009; Martineau, 2012). This so-called 'isotope salt effect' depends on the salt type and salt concentration. These factors change the activity in the fluid and therefore shift the isotope ratios measured by the equilibration method. Consequently, correction factors have to be applied to these analytical data. Direct conversion techniques like pyrolysis or the new laser instruments allow the measurement of the water molecule from the sample directly and should therefore not suffer from the salt effect, i.e. no corrections of raw values are necessary. However, due to high salt concentrations this might cause technical problems with the analytical hardware and may require labor-intensive sample preparation (e.g. vacuum distillation). This study evaluates the salt isotope effect for the IRMS equilibration technique (Thermo Gasbench II coupled to Delta Plus XP) and the laser-based IRIS instruments with liquid injection (Picarro L2120-i). Synthetic salt solutions (NaCl, KCl, CaCl2, MgCl2, MgSO4, CaSO4) and natural brines collected from the Stassfurt Salt Anticline (Germany; Stadler et al., 2012) were analysed with both techniques. Salt concentrations ranged from seawater salinity

  5. Expanding the isotopic toolbox: Applications of hydrogen and oxygen stable isotope ratios to food web studies

    Directory of Open Access Journals (Sweden)

    Hannah B Vander Zanden

    2016-03-01

    Full Text Available The measurement of stable carbon (δ13C and nitrogen (δ15N isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H and oxygen (δ18O isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applications using δ2H and, to a lesser extent, δ18O values have demonstrated potential for these elements to provide novel insights in modern food web studies. We explore the advantages and challenges associated with three applications of δ2H and δ18O values in food web studies. First, large δ2H differences between aquatic and terrestrial ecosystem end members can permit the quantification of energy inputs and nutrient fluxes between these two sources, with potential applications for determining allochthonous vs. autochthonous nutrient sources in freshwater systems and relative aquatic habitat utilization by terrestrial organisms. Next, some studies have identified a relationship between δ2H values and trophic position, which suggests that this marker may serve as a trophic indicator, in addition to the more commonly used δ15N values. Finally, coupled measurements of δ2H and δ18O values are increasing as a result of reduced analytical challenges to measure both simultaneously and may provide additional ecological information over single element measurements. In some organisms, the isotopic ratios of these two elements are tightly coupled, whereas the isotopic disequilibrium in other organisms may offer insight into the diet and physiology of individuals. Although a coherent framework for interpreting δ2H and δ18O data in the context of food web studies is emerging, many fundamental uncertainties remain. We highlight directions for targeted research that

  6. Expanding the isotopic toolbox: Applications of hydrogen and oxygen stable isotope ratios to food web studies

    OpenAIRE

    Hannah B Vander Zanden; David X Soto; Gabriel J Bowen; Keith A Hobson; Keith A Hobson

    2016-01-01

    The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicat...

  7. Expanding the Isotopic Toolbox: Applications of Hydrogen and Oxygen Stable Isotope Ratios to Food Web Studies

    OpenAIRE

    Vander Zanden, Hannah B.; Soto, David X.; Bowen, Gabriel J.; Hobson, Keith A.

    2016-01-01

    The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicatio...

  8. Caution on the use of liquid nitrogen traps in stable hydrogen isotope-ratio mass spectrometry

    Science.gov (United States)

    Coplen, Tyler B.; Qi, Haiping

    2010-01-01

    An anomalous stable hydrogen isotopic fractionation of 4 ‰ in gaseous hydrogen has been correlated with the process of adding liquid nitrogen (LN2) to top off the dewar of a stainless-steel water trap on a gaseous hydrogen-water platinum equilibration system. Although the cause of this isotopic fractionation is unknown, its effect can be mitigated by (1) increasing the capacity of any dewars so that they do not need to be filled during a daily analytic run, (2) interspersing isotopic reference waters among unknowns, and (3) applying a linear drift correction and linear normalization to isotopic results with a program such as Laboratory Information Management System (LIMS) for Light Stable Isotopes. With adoption of the above guidelines, measurement uncertainty can be substantially improved. For example, the long-term (months to years) δ2H reproducibility (1& sigma; standard deviation) of nine local isotopic reference waters analyzed daily improved substantially from about 1‰ to 0.58 ‰. This isotopically fractionating mechanism might affect other isotope-ratio mass spectrometers in which LN2 is used as a moisture trap for gaseous hydrogen

  9. Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning

    NARCIS (Netherlands)

    Haumann, F.A.; Batenburg, A.M.; Pieterse, G.; Gerbig, C.; Krol, M.C.; Rockmann, T.

    2013-01-01

    In this study, we identify a biomass-burning signal in molecular hydrogen (H-2) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H-2 and several other species as well as the H-2 isotopic composition in air samples that were collected in the BARCA

  10. Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning

    NARCIS (Netherlands)

    Haumann, F.A.; Batenburg, A.M.; Pieterse, G.; Gerbig, C; Krol, M.C.; Röckmann, T.

    2013-01-01

    In this study, we identify a biomass-burning signal in molecular hydrogen (H2) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H2 and several other species as well as the H2 isotopic composition in air samples that were collected in the BARCA (Balanço

  11. Hydrogen and oxygen isotope ratios of geothermal waters in the southern hachimantai area

    International Nuclear Information System (INIS)

    Matsubaya, Osamu; Etchu, Hiroshi; Takenaka, Teruo; Yoshida, Yutaka.

    1985-01-01

    Geothermal waters from the Matsukawa and Kakkonda Geothermal Plants, wells at Amihari-Motoyu, and Nyuto and Tazawako areas were isotopically studied. The geothermal waters from Mutsukawa, Kakkonda and Amihari-Motoyu have hydrogen isotope ratios similar to the local meteoric waters, while have higher oxygen isotope ratios than the local meteoric waters. This relationship of hydrogen and oxygen isotope ratios, that is called ''oxygen shift'', means that these geothermal waters are meteoric waters undergone the oxygen isotope exchange with rocks at high temperature of underground. The exygen shifts are 2 -- 3 per mil in Matsukawa and Kakkonda, and 7 per mil in Amihari-Motoyu. This difference may be important to understand the processe of water-rock interaction in this area. The geothermal waters at Nyuto and Tazawako areas also show 2 -- 3 per mil oxygen shift. The steam from the Tazawako-cho well and the hot spring water form the Tsurunoyu are estimated to be vapor and liquid phases separated form a single geothermal water of NaCl type, though the hot water from the Tsurunoyu is diluted with shallow meteoric water. (author)

  12. Hydrogen and oxygen stable isotope ratios of milk in the United States.

    Science.gov (United States)

    Chesson, Lesley A; Valenzuela, Luciano O; O'Grady, Shannon P; Cerling, Thure E; Ehleringer, James R

    2010-02-24

    Models of hydrogen and oxygen incorporation in human tissues recognize the impact of geographic location on the isotopic composition of fluid intake, but inputs can include nonlocal beverages, such as milk. Milk and cow drinking water were collected from dairies, and commercially available milk was purchased from supermarkets and fast food restaurants. It was hypothesized that milk water delta(2)H and delta(18)O values record geographic location information. Correlations between milk water isotope ratios and purchase location tap water were significant. However, the amount of variation in milk delta(2)H and delta(18)O values explained by tap water was low, suggesting a single estimation of fluid input isotope ratios may not always be adequate in studies. The delta(2)H and delta(18)O values of paired milk and cow drinking water were related, suggesting potential for geographical origin assignment using stable isotope analysis. As an application example, milk water delta(18)O values were used to predict possible regions of origin for restaurant samples.

  13. Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning

    Science.gov (United States)

    Haumann, F. A.; Batenburg, A. M.; Pieterse, G.; Gerbig, C.; Krol, M. C.; Röckmann, T.

    2013-09-01

    In this study, we identify a biomass-burning signal in molecular hydrogen (H2) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H2 and several other species as well as the H2 isotopic composition in air samples that were collected in the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) aircraft campaign during the dry season. We derive a relative H2 emission ratio with respect to carbon monoxide (CO) of 0.31 ± 0.04 ppb ppb-1 and an isotopic source signature of -280 ± 41‰ in the air masses influenced by tropical biomass burning. In order to retrieve a clear source signal that is not influenced by the soil uptake of H2, we exclude samples from the atmospheric boundary layer. This procedure is supported by data from a global chemistry transport model. The ΔH2 / ΔCO emission ratio is significantly lower than some earlier estimates for the tropical rainforest. In addition, our results confirm the lower values of the previously conflicting estimates of the H2 isotopic source signature from biomass burning. These values for the emission ratio and isotopic source signatures of H2 from tropical biomass burning can be used in future bottom-up and top-down approaches aiming to constrain the strength of the biomass-burning source for H2. Hitherto, these two quantities relied only on combustion experiments or on statistical relations, since no direct signal had been obtained from in-situ observations.

  14. Changes in hydrogen isotope ratios in sequential plumage stages: an implication for the creation of isotope-base maps for tracking migratory birds.

    Science.gov (United States)

    Duxbury, J M; Holroyd, G L; Muehlenbachs, K

    2003-09-01

    Accurate reference maps are important in the use of stable-isotopes to track the movements of migratory birds. Reference maps created by the analysis of samples collected from young at the nest site are more accurate than simply referring to naturally occurring patterns of hydrogen isotope ratios created by precipitation cycles. Ratios of hydrogen isotopes in the nutrients incorporated early in the development of young birds can be derived from endogenous, maternal sources. Base-maps should be created with the analysis of tissue samples from hatchlings after local the isotopic signature of exogenous nutrients is dominant. Migratory species such as Peregrine Falcons are known to use endogenous sources in the creation of their eggs, therefore knowledge of what plumage stage best represents the local hydrogen ratios would assist in the planning of nest visits. We conducted diet manipulation experiments involving Japanese Quail and Peregrine Falcons to determine the plumage stage when hydrogen isotope ratios were indicative of a switch in their food source. The natal down of both the quail and falcons reflected the diet of breeding adult females. The hydrogen isotope ratios of a new food source were dominant in the juvenile down of the young falcons, although a further shift was detected in the final juvenile plumage. The juvenile plumage is grown during weeks 3-4 after hatch on Peregrine Falcons. Nest visits for the purpose of collecting feathers for isotope-base-map creation should be made around 4 weeks after the presumed hatch of the young falcons.

  15. A new sniffer probe for the determination of hydrogen isotope ratios in the W7-AS stellarator

    Science.gov (United States)

    Zebisch, P.; Taglauer, E.

    1999-07-01

    An improved sniffer probe was constructed for measurements of the hydrogen isotope ratio and impurities in the plasma edge of the W7-AS stellarator. Details of the new design and the probe performance are presented. The new design allows changing the head without breaking the vacuum in the torus. It has a high mechanical stability, effective screening of the magnetic field and high sensitivity. The gas dynamic properties of the probe are analyzed using transmission line calculus, resulting in a rise time of 114 ms for hydrogen. During the 1997 spring measurement campaign, H/D isotope ratio measurements were carried through showing considerable outgassing of the walls during and after the discharge. He glow discharges reduce the isotope ratio drastically. Results from a typical experiment day are presented together with the analytic procedure for determining the isotope ratio in both the plasma edge and in the neutral gas region between the plasma and the vessel walls.

  16. Seasonal Variations in Stable Isotope Ratios of Oxygen and Hydrogen in Two Tundra Rivers in NE European Russia

    Energy Technology Data Exchange (ETDEWEB)

    Huitu, E.; Arvola, L. [Lammi Biological Station, University of Helsinki (Finland); Sonninen, E. [Radiocarbon Dating Laboratory, University of Helsinki (Finland)

    2013-07-15

    The variability in stable isotope ratios of oxygen and hydrogen ({delta} {sup 18}O and {delta}{sup 2}H values) in river waters in northeast European Russia was studied for the period from July 2007 to october 2008. Exceptional isotope composition in precipitation obtained during the sampling period was clearly traced in the composition of river waters. Water from permafrost thawing did not make a great contribution to river flow. (author)

  17. Optimization of on-line hydrogen stable isotope ratio measurements of halogen- and sulfur-bearing organic compounds using elemental analyzer–chromium/high-temperature conversion isotope ratio mass spectrometry (EA-Cr/HTC-IRMS)

    Science.gov (United States)

    Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B.; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A.; Schimmelmann, Arndt

    2017-01-01

    Rationale: Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H2) is responsible for non-quantitative H2 yields and possible hydrogen isotopic fractionation. Our previously introduced, new chromium-based EA-Cr/HTC-IRMS (Elemental Analyzer–Chromium/High-Temperature Conversion Isotope Ratio Mass Spectrometry) technique focused primarily on nitrogen-bearing compounds. Several technical and analytical issues concerning halogen- and sulfur-bearing samples, however, remained unresolved and required further refinement of the reactor systems.

  18. Oxygen and hydrogen isotope ratios in tree rings: how well do models predict observed values?

    CSIR Research Space (South Africa)

    Waterhouse, JS

    2002-07-30

    Full Text Available . Cosmo- chim. Acta 46 (1982) 955^965. [35] W.M. Buhay, T.W.D. Edwards, Climate in southwestern Ontario, Canada, between AD 1610 and 1885 inferred from oxygen and hydrogen isotopic measurements of wood cellulose from trees in di?erent hydrological set...

  19. Removal method of fluorescent dyes as pretreatment for measurement of major ion concentrations and hydrogen and oxygen isotopic ratios

    International Nuclear Information System (INIS)

    Nakata, Kotaro; Hasegawa, Takuma; Kashiwaya, Koki; Kodama, Hiroki; Miyajima, Tohru

    2011-01-01

    The major ion concentration and isotope ratio of hydrogen and oxygen can provide important information for migration of groundwater. Sometimes, quantitative estimation of these chemical and isotopic characteristics of solution is necessary for groundwater containing fluorescent dyes, which are used in drilling borehole and tracer experiments. However, sometimes correct estimation is disturbed by dyes and they become a cause of troubles for measurement equipments. Thus development of method to remove dyes is required so that the characteristics of groundwater can be estimated without the negative effect of dyes on measurement or equipments. In this study, removal of four representative dyes (Uranin, Eosin, Naphthalenesulfonic acid sodium(NAP) and Amino G acid potassium salt (AG)) was investigated. Uranin and Eosin were found to be removed by non-ionic synthetic resin: HP2MG. 99.99% of the dyes were removed from initial solutions containing dyes with 10 mg/L after contact with resin, while the contact had little effect on ion concentrations and oxygen and hydrogen isotope ratios. Thus the chemical and isotopic characteristics of groundwater samples containing Uranin and Eosin can be obtained by using the HP2MG resin. On the other hand, the NAP and AG were found to be difficult to remove by the HP2MG resin but they were able to be removed by anion exchange resin (Dowex 1x8). Though contact of solution with Dowex 1x8 did not affect cation concentrations and hydrogen and oxygen isotope ratios, anion concentrations were changed by the contact. Therefore the Dowex 1x8 is only applicable to estimation of the cation concentrations and isotope ratio of hydrogen and oxygen. When both anion and cation concentrations from the samples were necessary, Uranin or Eosin were recommended as a tracer in drilling or tracer experiments. (author)

  20. New manuscript guidelines for the reporting of stable hydrogen, carbon, and oxygen isotope-ratio data

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-10-01

    To eliminate possible confusion in the reporting of isotopic abundances on non-corresponding scales, the Commission on Atomic Weights and Isotopic Abundances recommended at the 37{sup th} General Assembly at Lisbon, Portugal that (i) {sup 2}H/{sup 1}H relative ratios of all substances be expressed relative to VSMOW (Vienna Standard Mean Ocean Water) on a scale such that {sup 2}H/{sup 1}H of SLAP (Standard Light Antartic Precipitation) is 0.572 times that of VSMOW, (ii) {sup 13}C/{sup 12}C relative ratios of all substances be expressed relative to VPDB (Vienna Peedee belemnite) on a scale such that {sup 13}C/{sup 12}C of NBS 19 carbonate is 1.00195 times that of VPDB, and (iii) {sup 18}O/{sup 16}O ratios of all substances be expressed relative to either VSMOW or VPDB on scales such that {sup 18}O/{sup 16}O of SLAP is 0.9445 times that of VSMOW. (Author)

  1. Continuous-flow isotope ratio mass spectrometry method for carbon and hydrogen isotope measurements on atmospheric methane

    Directory of Open Access Journals (Sweden)

    M. Brass

    2010-12-01

    Full Text Available We describe a continuous-flow isotope ratio mass spectrometry (CF-IRMS technique for high-precision δD and δ13C measurements of atmospheric methane on 40 mL air samples. CH4 is separated from other air components by utilizing purely physical processes based on temperature, time and mechanical valve switching. Chemical agents are avoided. Trace amounts of interfering compounds can be separated by gas chromatography after pre-concentration of the CH4 sample. The purified sample is then either combusted to CO2 or pyrolyzed to H2 for stable isotope measurement. Apart from connecting samples and refilling liquid nitrogen as coolant the system is fully automated and allows an unobserved, continuous analysis of samples. The analytical system has been used for analysis of air samples with CH4 mixing ratios between ~100 and ~10 000 ppb, for higher mixing ratios samples usually have to be diluted.

  2. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1985-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers. 6 refs., 3 figs., 3 tabs

  3. Detecting isotopic ratio outliers

    Science.gov (United States)

    Bayne, C. K.; Smith, D. H.

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers.

  4. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1986-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers

  5. Biomedical and Forensic Applications of Combined Catalytic Hydrogenation-Stable Isotope Ratio Analysis

    Directory of Open Access Journals (Sweden)

    Mark A. Sephton

    2007-01-01

    Full Text Available Studies of biological molecules such as fatty acids and the steroid hormones have the potential to benefit enormously from stable carbon isotope ratio measurements of individual molecules. In their natural form, however, the body’s molecules interact too readily with laboratory equipment designed to separate them for accurate measurements to be made.Some methods overcome this problem by adding carbon to the target molecule, but this can irreversibly overprint the carbon source ‘signal’. Hydropyrolysis is a newly-applied catalytic technique that delicately strips molecules of their functional groups but retains their carbon skeletons and stereochemistries intact, allowing precise determination of the carbon source. By solving analytical problems, the new technique is increasing the ability of scientists to pinpoint molecular indicators of disease, elucidate metabolic pathways and recognise administered substances in forensic investigations.

  6. Biomedical and Forensic Applications of Combined Catalytic Hydrogenation-Stable Isotope Ratio Analysis

    Science.gov (United States)

    Sephton, Mark A.; Meredith, Will; Sun, Cheng-Gong; Snape, Colin E.

    2007-01-01

    Studies of biological molecules such as fatty acids and the steroid hormones have the potential to benefit enormously from stable carbon isotope ratio measurements of individual molecules. In their natural form, however, the body’s molecules interact too readily with laboratory equipment designed to separate them for accurate measurements to be made. Some methods overcome this problem by adding carbon to the target molecule, but this can irreversibly overprint the carbon source ‘signal’. Hydropyrolysis is a newly-applied catalytic technique that delicately strips molecules of their functional groups but retains their carbon skeletons and stereochemistries intact, allowing precise determination of the carbon source. By solving analytical problems, the new technique is increasing the ability of scientists to pinpoint molecular indicators of disease, elucidate metabolic pathways and recognise administered substances in forensic investigations. PMID:19662175

  7. The relationship between stable oxygen and hydrogen isotope ratios of water in astomatal plants

    Science.gov (United States)

    Cooper, Lee W.; DeNiro, Michael J.; Keeley, Jon E.; Taylor, H. P.; O'Neil, J. R.; Kaplan, I.R.

    1991-01-01

    Isotropic fractination of leaf water during transpiration is influenced by both equilibrium and kinetic factors. Previous workers have predicted that the influence of each factor varies depending upon the path of water loss,m whether centralized through stomata, or diffuse through the cuticle. We studied the relationship between the δD and δ18O values of lead and stem waters of laurel sumac, Rhus laurina (Nutt.) T. & G., and its parasite, dodder, Cuscuta subinclusa D. & H., growing in the field. Stomatal transpiration, associated with more stagnant boundary layers, predominates in R. laurina; cuticular transpiration, associated with more turbulent boundary layers, is most important in the largely astomatal C. subinclusa. We also studied the diurnal variation in the δD and δ18O values of lead waters of two astomatal plants, Chiloschista lunifera (Rchb. F.) J.J.S. and Stylites andicola Amstutz, and two stomatal plants, Tillandsia balbisiana Schult. and Lilaeopsis schaffneriana (Schlecht.) C. & R., growing with them under the same conditions in the laboratory. Slopes, m, for the relation δD = mδ18O + b were significantly higher for stem waters in C. subinclusa that for leaf waters in R. laurina (1.77), consistent with the difference in the boundary layers through which water was lost in the two species. The magnitude of diurnal heavy isotope enrichment of tissue water was smaller in C. subinclusa than in R. laurina, which is also consistent with predictions concerning evapotranspiration through difference types of boundary layers. The slopes, m, in plant waters in the laboratory experiments, conducted at high humidity, were not different than those observed during evaporation of water from pans, regardless of plant anatomy. The observation suggests that cuticular transpiration is important in influencing isotopic fractionation of water only at low humidity. Our results indicate that the isotopic composition of water vapor released by plants in arid regions may

  8. A Novel Framework for Quantifying past Methane Recycling by Sphagnum-Methanotroph Symbiosis Using Carbon and Hydrogen Isotope Ratios of Leaf Wax Biomarkers

    Science.gov (United States)

    Nichols, Jonathan E.; Isles, Peter D. F.; Peteet, Dorothy M.

    2014-01-01

    The concentration of atmospheric methane is strongly linked to variations in Earth's climate. Currently, we can directly reconstruct the total atmospheric concentration of methane, but not individual terms of the methane cycle. Northern wetlands, dominated by Sphagnum, are an important contributor of atmospheric methane, and we seek to understand the methane cycle in these systems. We present a novel method for quantifying the proportion of carbon Sphagnum assimilates from its methanotrophic symbionts using stable isotope ratios of leaf-wax biomarkers. Carbon isotope ratios of Sphagnum compounds are determined by two competing influences, water content and the isotope ratio of source carbon. We disentangled these effects using a combined hydrogen and carbon isotope approach. We constrained Sphagnum water content using the contrast between the hydrogen isotope ratios of Sphagnum and vascular plant biomarkers. We then used Sphagnum water content to calculate the carbon isotope ratio of Sphagnum's carbon pool. Using a mass balance equation, we calculated the proportion of recycled methane contributed to the Sphagnum carbon pool, 'PRM.' We quantified PRM in peat monoliths from three microhabitats in the Mer Bleue peatland complex. Modern studies have shown that water table depth and vegetation have strong influences on the peatland methane cycle on instrumental time scales. With this new approach, delta C-13 of Sphagnum compounds are now a useful tool for investigating the relationships among hydrology, vegetation, and methanotrophy in Sphagnum peatlands over the time scales of entire peatland sediment records, vital to our understanding of the global carbon cycle through the Late Glacial and Holocene.

  9. Carbon and hydrogen isotope ratios of bacterial methane and its formation mechanism

    International Nuclear Information System (INIS)

    Sugimoto, A.; Wada, E.

    1993-01-01

    Anaerobic incubations of paddy soil collected from Konosu, Japan, were carried out for 10 weeks to clarify the general principles that govern the variation of carbon isotopic composition of bacterial methane from freshwater areas. The δ 13 C value of produced CH 4 was highly variable ranging from -60 to -33%, corresponding to change in its formation pathways: acetate fermentation and CO 2 /H 2 reduction. The δ 13 C value of CH 4 from CO 2 /H 2 was estimated as -77 to -60%, adopting 45% of δ 13 C difference between the CH 4 and its source CO 2 . The δ 13 C value of methyl carbon of acetate accumulated with addition of inhibitor for methanogenesis ranged from -43 to -30%, which was considered with the δ 13 C value of CH 4 from acetate. Variability of CH 4 δ 13 C resulted from the difference in contribution of each biological process. It was demonstrated that δ 13 C value of methane was a useful indicator for assessing the contribution of each process in wetlands and paddy fields. (author)

  10. Optimization of on-line hydrogen stable isotope ratio measurements of halogen- and sulfur-bearing organic compounds using elemental analyzer-chromium/high-temperature conversion isotope ratio mass spectrometry (EA-Cr/HTC-IRMS).

    Science.gov (United States)

    Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A; Schimmelmann, Arndt

    2017-03-30

    Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H 2 ) is responsible for non-quantitative H 2 yields and possible hydrogen isotopic fractionation. Our previously introduced, new chromium-based EA-Cr/HTC-IRMS (Elemental Analyzer-Chromium/High-Temperature Conversion Isotope Ratio Mass Spectrometry) technique focused primarily on nitrogen-bearing compounds. Several technical and analytical issues concerning halogen- and sulfur-bearing samples, however, remained unresolved and required further refinement of the reactor systems. The EA-Cr/HTC reactor was substantially modified for the conversion of halogen- and sulfur-bearing samples. The performance of the novel conversion setup for solid and liquid samples was monitored and optimized using a simultaneously operating dual-detection system of IRMS and ion trap MS. The method with several variants in the reactor, including the addition of manganese metal chips, was evaluated in three laboratories using EA-Cr/HTC-IRMS (on-line method) and compared with traditional uranium-reduction-based conversion combined with manual dual-inlet IRMS analysis (off-line method) in one laboratory. The modified EA-Cr/HTC reactor setup showed an overall H 2 -recovery of more than 96% for all halogen- and sulfur-bearing organic compounds. All results were successfully normalized via two-point calibration with VSMOW-SLAP reference waters. Precise and accurate hydrogen isotopic analysis was achieved for a variety of organics containing F-, Cl-, Br-, I-, and S-bearing heteroelements. The robust nature of the on-line EA-Cr/HTC technique was demonstrated by a series of 196 consecutive measurements with a single reactor filling. The optimized EA-Cr/HTC reactor design can be implemented in existing analytical equipment using commercially available material and

  11. Water Table Depth Reconstruction in Ombrotrophic Peatlands Using Biomarker Abundance Ratios and Compound-Specific Hydrogen Isotope Composition

    Science.gov (United States)

    Nichols, J. E.; Jackson, S. T.; Booth, R. K.; Pendall, E. G.; Huang, Y.

    2005-12-01

    Sediment cores from ombrotrophic peat bogs provide sensitive records of changes in precipitation/evaporation (P/E) balance. Various proxies have been developed to reconstruct surface moisture conditions in peat bogs, including testate amoebae, plant macrofossils, and peat humification. Studying species composition of testate amoeba assemblages is time consuming and requires specialized training. Humification index can be influenced by environmental factors other than moisture balance. The plant macrofossil proxy is less quantitative and cannot be performed on highly decomposed samples. We demonstrate that the ratio of C23 alkane to C29 alkane abundance may provide a simple alternative or complementary means of tracking peatland water-table depth. Data for this proxy can be collected quickly using a small sample (100 mg dry). Water-table depth decreases during drought, and abundance of Sphagnum, the dominant peat-forming genus, decreases as vascular plants increase. Sphagnum moss produces mainly medium chain-length alkanes (C21-C25) while vascular plants (grasses and shrubs) produce primarily longer chain-length alkanes (C27-C31). Therefore, C23:C29 n-alkane ratios quantitatively track the water table depth fluctuations in peat bogs. We compared C23:C29 n-alkane ratios in a core from Minden Bog (southeastern Michigan) with water table depth reconstructions based on testate-amoeba assemblages and humification. The 184-cm core spans the past ~3kyr of continuous peat deposition in the bog. Our results indicate that the alkane ratios closely track the water table depth variations, with C29 most abundant during droughts. We also explored the use of D/H ratios in Sphagnum biomarkers as a water-table depth proxy. Compound-specific hydrogen isotope ratio analyses were performed on Sphagnum biomarkers: C23 and C25 alkane and C24 acid. Dry periods are represented in these records by an enrichment of deuterium in these Sphagnum-specific compounds. These events also correlate

  12. Chromatographic hydrogen isotope separation

    International Nuclear Information System (INIS)

    Aldridge, F.T.

    1983-01-01

    Intermetallic compounds with the CaCu5 type of crystal structure, particularly LaNiCo and CaNi5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors

  13. Chromatographic hydrogen isotope separation

    International Nuclear Information System (INIS)

    Aldridge, F.T.

    1981-01-01

    Intermetallic compounds with the CaCu5 type of crystal structure , particularly LaNiCo and CaNi5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors

  14. A measuring system for the fast simultaneous isotope ratio and elemental analysis of carbon, hydrogen, nitrogen and sulfur in food commodities and other biological material.

    Science.gov (United States)

    Sieper, Hans-Peter; Kupka, Hans-Joachim; Williams, Tony; Rossmann, Andreas; Rummel, Susanne; Tanz, Nicole; Schmidt, Hanns-Ludwig

    2006-01-01

    The isotope ratio of each of the light elements preserves individual information on the origin and history of organic natural compounds. Therefore, a multi-element isotope ratio analysis is the most efficient means for the origin and authenticity assignment of food, and also for the solution of various problems in ecology, archaeology and criminology. Due to the extraordinary relative abundances of the elements hydrogen, carbon, nitrogen and sulfur in some biological material and to the need for individual sample preparations for H and S, their isotope ratio determination currently requires at least three independent procedures and approximately 1 h of work. We present here a system for the integrated elemental and isotope ratio analysis of all four elements in one sample within 20 min. The system consists of an elemental analyser coupled to an isotope ratio mass spectrometer with an inlet system for four reference gases (N(2), CO(2), H(2) and SO(2)). The combustion gases are separated by reversible adsorption and determined by a thermoconductivity detector; H(2)O is reduced to H(2). The analyser is able to combust samples with up to 100 mg of organic material, sufficient to analyse samples with even unusual elemental ratios, in one run. A comparison of the isotope ratios of samples of water, fruit juices, cheese and ethanol from wine, analysed by the four-element analyser and by classical methods and systems, respectively, yielded excellent agreements. The sensitivity of the device for the isotope ratio measurement of C and N corresponds to that of other systems. It is less by a factor of four for H and by a factor of two for S, and the error ranges are identical to those of other systems. Copyright (c) 2006 John Wiley & Sons, Ltd.

  15. Observations of molecular hydrogen mixing ratio and stable isotopic composition at the Cabauw tall tower in the Netherlands

    Science.gov (United States)

    Batenburg, A. M.; Popa, M. E.; Vermeulen, A. T.; van den Bulk, W. C. M.; Jongejan, P. A. C.; Fisher, R. E.; Lowry, D.; Nisbet, E. G.; Röckmann, T.

    2016-12-01

    Measurements of the stable isotopic composition (δD(H2) or δD) of atmospheric molecular hydrogen (H2) are a useful addition to mixing ratio (χ(H2)) measurements for understanding the atmospheric H2 cycle. δD datasets published so far consist mostly of observations at background locations. We complement these with observations from the Cabauw tall tower at the CESAR site, situated in a densely populated region of the Netherlands. Our measurements show a large anthropogenic influence on the local H2 cycle, with frequently occurring pollution events that are characterized by χ(H2) values that reach up to ≈1 ppm and low δD values. An isotopic source signature analysis yields an apparent source signature below -400‰, which is much more D-depleted than the fossil fuel combustion source signature commonly used in H2 budget studies. Two diurnal cycles that were sampled at a suburban site near London also show a more D-depleted source signature (≈-340‰), though not as extremely depleted as at Cabauw. The source signature of the Northwest European vehicle fleet may have shifted to somewhat lower values due to changes in vehicle technology and driving conditions. Even so, the surprisingly depleted apparent source signature at Cabauw requires additional explanation; microbial H2 production seems the most likely cause. The Cabauw tower site also allowed us to sample vertical profiles. We found no decrease in χ(H2) at lower sampling levels (20 and 60 m) with respect to higher sampling levels (120 and 200 m). There was a significant shift to lower median δD values at the lower levels. This confirms the limited role of soil uptake around Cabauw, and again points to microbial H2 production during an extended growing season, as well as to possible differences in average fossil fuel combustion source signature between the different footprint areas of the sampling levels. So, although knowledge of the background cycle of H2 has improved over the last decade, surprising

  16. A 10-yr record of stable isotope ratios of hydrogen and oxygen in precipitation at Calgary, Alberta, Canada

    International Nuclear Information System (INIS)

    Peng, Haidong; Mayer, Bernhard; Krouse, H. Roy; Harris, Stuart

    2004-01-01

    Short-term (0.5-3 d) precipitation samples were collected from January 1992 to December 2001 in Calgary, Alberta, Canada, and the stable isotope ratios of hydrogen ( 2 H/ 1 H) and oxygen ( 18 O/ 16 O) for these samples were determined. The 10-yr amount-weighted average δ 2 H and δ 18 O values of precipitation were -136.1 per mill and -17.9 per mill, respectively. Consistent with IAEA established practice, the following local meteoric water line (LMWL) for Calgary was derived using amount-weighted monthly average δ 2 H and δ 18 O values: δ 2 H = 7.68 δ 18 O -0.21 (r 2 = 0.96, n= 104) . The correlation equation between δ 2 H and δ 18 O values from individual samples was found to be δ 2 H = 7.10 δ 18 O -13.64 (r 2 = 0.95, n= 839) , which is different from the LMWL, exhibiting lower slope and intercept values. A comparison of δ 2 H and δ 18 O correlation equations with temperature during precipitation events showed a trend of decreasing slopes and intercepts with increasing temperature. Our data suggest that this is caused by incorporation of moisture derived from evaporation from water bodies and soils along the storm paths and by secondary evaporation between the cloud base and the ground during precipitation events. These processes compromise the usefulness of d-excess values as an indicator for the meteorological conditions in the maritime source regions. The δ 18 O temperature dependence at Calgary was found to be ∼ 0.44 per mill/deg C. The study shows that short-term sampling of individual precipitation events yields valuable information, which is not obtainable by the widely used monthly collection programs

  17. A 10-yr record of stable isotope ratios of hydrogen and oxygen in precipitation at Calgary, Alberta, Canada

    Science.gov (United States)

    Peng, Haidong; Mayer, Bernhard; Harris, Stuart; Krouse, H. Roy

    2004-04-01

    Short-term (0.5 3 d) precipitation samples were collected from January 1992 to December 2001 in Calgary, Alberta, Canada, and the stable isotope ratios of hydrogen (2H/1H) and oxygen (18O/16O) for these samples were determined. The 10-yr amount-weighted average δ2H and δ18O values of precipitation were -136.1‰ and -17.9‰, respectively. Consistent with International Atomic Energy Agency (IAEA) established practice, the following local meteoric water line (LMWL) for Calgary was derived using amount-weighted monthly average δ2H and δ18O values: δ2H = 7.68 δ18O -0.21 (r2= 0.96, n= 104). The correlation equation between δ2H and δ18O values from individual samples was found to be δ2H = 7.10 δ18O -13.64 (r2= 0.95, n= 839), which is different from the LMWL, exhibiting lower slope and intercept values. A comparison of δ2H and δ18O correlation equations with temperature during precipitation events showed a trend of decreasing slopes and intercepts with increasing temperature. Our data suggest that this is caused by incorporation of moisture derived from evaporation from water bodies and soils along the storm paths and by secondary evaporation between the cloud base and the ground during precipitation events. These processes compromise the usefulness of d-excess values as an indicator for the meteorological conditions in the maritime source regions. The δ18O temperature dependence at Calgary was found to be 0.44‰°C1. The study shows that short-term sampling of individual precipitation events yields valuable information, which is not obtainable by the widely used monthly collection programs.

  18. Container for hydrogen isotopes

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-12

    A container is described for storage, shipping and and dispensing of hydrogen isotopes such as hydrogen, deuterium, tritium, or mixtures of the same. The container is compact, safe against fracture or accident, and is reusable. It consists of an outer housing with suitable inlet and outlet openings and electrical feed elements, the housing containing an activated sorber material in the form, for example of titanium sponge or an activated zirconium aluminate cartridge. The gas to be stored is introduced into the chamber under conditions of heat and vacuum and is retained in the sorber material. Subsequently, it may be released by heating the unit to drive off the stored gas at desired rates.

  19. Container for hydrogen isotopes

    International Nuclear Information System (INIS)

    1976-01-01

    A container is described for storage, shipping and and dispensing of hydrogen isotopes such as hydrogen, deuterium, tritium, or mixtures of the same. The container is compact, safe against fracture or accident, and is reusable. It consists of an outer housing with suitable inlet and outlet openings and electrical feed elements, the housing containing an activated sorber material in the form, for example of titanium sponge or an activated zirconium aluminate cartridge. The gas to be stored is introduced into the chamber under conditions of heat and vacuum and is retained in the sorber material. Subsequently, it may be released by heating the unit to drive off the stored gas at desired rates

  20. Electrochemical hydrogen isotope sensor based on solid electrolytes

    International Nuclear Information System (INIS)

    Matsumoto, Hiroshige; Hayashi, Hiroyuki; Iwahara, Hiroyasu

    2002-01-01

    An electrochemical sensor of hydrogen isotopes based on solid electrolytes for determining the hydrogen isotope ratios and/or total hydrogen pressures in gases has been developed. This paper describes the methodology of the hydrogen isotope sensing together with experimental results. When hydrogen isotope gases are introduced to an electrochemical cell using a proton-conducting electrolyte (hydrogen isotope cell), the electromotive force (EMF) of the cell agrees with that theoretically estimated. The EMF signals can be used for the determination of the hydrogen isotope ratio in gases if the total hydrogen pressure is predetermined. By supplementary use of an oxide ion conductor cell, both the ratio and total pressure of the hydrogen isotopes can be simultaneously determined. (author)

  1. Hydrogen isotope technology

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    Hydrogen pumping speeds on panels of molecular sieve types 5A and Na-Y were compared for a variety of sieve (and chevron) temperatures between 10 and 30 K. Although pumping speeds declined with time, probably because of the slow diffusion of hydrogen from the surface of the sieve crystals into the internal regions, the different sieve materials and operating conditions could be compared using time-averaged pump speeds. The (average) pumping speeds declined with increasing temperature. Under some conditions, the Na-Y sieve performed much better than the 5A sieve. Studies of the effect of small concentrations (approx. 4%) of hydrogen on helium pumping indicate that compound cryopumps in fusion reactors will not have to provide complete screening of hydrogen from helium panels. The concentrations of hydrogen did not lower effective helium pumping speeds or shorten the helium operating period between instabilities. Studies of tritium recovery from blankets of liquid lithium focused on design and construction of a flowing-lithium test system and on ultimate removal of tritium from yttrium sorbents. At 505 0 C, tritium release from yttrium behaves as a diffusion-controlled process, but the release rates are very low. Apparently, higher temperatures will be required for effective sorbent regeneration. An innovative technique for separating hydrogen isotopes by using bipolar electrolysis with permeable electrodes was analyzed to determine its potential usefulness in multistage separation

  2. Noncovalent Hydrogen Isotope Effects

    Science.gov (United States)

    Buchachenko, A. L.; Breslavskaya, N. N.

    2018-02-01

    Zero-point energies (ZPE) and isotope effects, induced by intermolecular, noncovalent vibrations, are computed and tested by experimental data. The ZPE differences of H- and D-complexes of water with hydrogen, methane, and water molecules are about 100-300 cal/mol; they result to isotope effects IE of 1.20-1.70. Semi-ionic bonds between metal ions and water ligands in M(H2O) 6 2+ complexes are much stronger; their ZPEs are about 12-14 kcal/mol per molecule and result to IE of 1.9-2.1 at 300 K. Protonated (deuterated) water and biwater exhibit the largest ZPE differences and isotope effects; the latter are 25-28 and 12-13 for water and biwater, respectively. Noncovalent IEs contribute markedly into the experimentally measured effects and explain many anomalous and even magic properties of the effects, such as the dependence of IE on the solvents and on the presence of the third substances, enormously large isotope effects at the mild conditions, the difference between IEs measured in the reactions of individual protiated and deuterated compounds and those measured in their mixture. Noncovalent IEs are not negligible and should be taken into account to make correct and substantiated conclusions on the reaction mechanisms. The kinetic equations are derived for the total isotope effects, which include noncovalent IEs as additive factors.

  3. Container for hydrogen isotopes

    International Nuclear Information System (INIS)

    Solomon, D.E.

    1977-01-01

    A container for the storage, shipping and dispensing of hydrogen isotopes such as hydrogen, deuterium, tritium, or mixtures of the same which has compactness, which is safe against fracture or accident, and which is reusable is described. The container consists of an outer housing with suitable inlet and outlet openings and electrical feed elements, the housing containing an activated sorber material in the form, for example, of titanium sponge or an activated zirconium aluminate cartridge. The gas to be stored is introduced into the chamber under conditions of heat and vacuum and will be retained in the sorber material. Subsequently, it may be released by heating the unit to drive off the stored gas at desired rates

  4. Compound-Specific Carbon, Nitrogen, and Hydrogen Isotopic Ratios for Amino Acids in CM and CR Chondrites and their use in Evaluating Potential Formation Pathways

    Science.gov (United States)

    Elsila, Jamie E.; Charnley, Steven B.; Burton, Aaron S.; Glavin, Daniel P.; Dworkin, Jason P.

    2012-01-01

    Stable hydrogen, carbon, and nitrogen isotopic ratios (oD, 013C, and olSN) of organic compounds can revcal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may indicate the most likely of these pathways. We have applied gas chromatography with mass spectrometry and combustion isotope ratio mass spectrometry to measure the compound-specific C, N, and H stable isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites: CM1I2 Allan Hills (ALH) 83100, CM2 Murchison, CM2 Lewis Cliff (LEW) 90500, CM2 Lonewolf Nunataks (LON) 94101, CRZ Graves Nunataks (GRA) 95229, CRZ Elephant Moraine (EET) 92042, and CR3 Queen Alexandra Range (QUE) 99177. We compare the isotopic compositions of amino acids in these meteorites with predictions of expected isotopic enrichments from potential formation pathways. We observe trends of decreasing ODC and increasing oD with increasing carbon number in the aH, (l-NH2 amino acids that correspond to predictions made for formation via Streckercyanohydrin synthesis. We also observe light ODC signatures for -alanine, which may indicate either formation via Michael addition or via a pathway that forms primarily small, straight-chain, amine-terminal amino acids (n-ro-amino acids). Higher deuterium enrichments are observed in amethyl amino acids, indicating formation of these amino acids or their precursors in cold interstellar or nebular environments. Finally, individual amino acids are more enriched in deuterium in CR chondrites than CM chondrites, reflecting different parent-body chemistry.

  5. Normalization of oxygen and hydrogen isotope data

    Science.gov (United States)

    Coplen, T.B.

    1988-01-01

    To resolve confusion due to expression of isotopic data from different laboratories on non-corresponding scales, oxygen isotope analyses of all substances can be expressed relative to VSMOW or VPDB (Vienna Peedee belemnite) on scales normalized such that the ??18O of SLAP is -55.5% relative to VSMOW. H3+ contribution in hydrogen isotope ratio analysis can be easily determined using two gaseous reference samples that differ greatly in deuterium content. ?? 1988.

  6. Melatonin labeled with hydrogen isotopes

    International Nuclear Information System (INIS)

    Dmitrevskaya, L.I.; Smushkevich, Yu.I.; Kurkovskaya, L.N.; Ponomarenko, N.K.; Suvorov, N.N.

    1989-01-01

    A study has been made of isotope exchange between melatonin and deuterium (D 2 O) or tritium (HTO) oxide under different conditions. The ease of isotope exchange for the indole ring hydrogens of melatonin in an acidic medium decreases over the series H 4 > H 2 H 6 >> H 7 , enabling the authors to process a route for production of melatonin labeled with hydrogen isotopes at positions 4,6, and 2 of the indole ring. A method has been suggested for producing melatonin labeled with hydrogen isotopes at position 2 by desulfurization of 2-(2,4-dinitro-phenylsulfenyl)melatonin at Ni(Re) (D)

  7. Melatonin labelled by hydrogen isotopes

    International Nuclear Information System (INIS)

    Dmitrevskaya, L.I.; Smushkevich, Yu.I.; Kurkovskaya, L.N.; Ponomarenko, N.K.; Suvorov, N.N.

    1988-01-01

    Isotope exchange of melatonin with deuterium (D 2 O) and tritium (HTO) oxides under different conditions is studied. Simplicity of isotope exchange of hydrogens of the indole ring of melatonin in the acidic medium decreases in series H 4 >H 2 >H 6 >>H 7 , that permits to suggest the way of melatonin preparation labelled by hydrogen isotopes in positions 4,6 and 2 of the indole ring. The way of melatonin preparation labelled by hydrogen isotopes in position 2 according to the reaction of desulfation 2-(2,4-dinitrophenylsulphenyl) melatonin at catalyst Ni(Re)(D) is suggested

  8. Hydrogen isotope ratios of terrestrial leaf wax n-alkanes from the Tibetan Plateau: Controls on apparent enrichment factors, effect of vapor sources and implication for altimetry

    Science.gov (United States)

    Zhang, Xiaolong; Xu, Baiqing; Günther, Franziska; Mügler, Ines; Lange, Markus; Zhao, Huabiao; Li, Jiule; Gleixner, Gerd

    2017-08-01

    Empirical evidence suggested that the altitudinal dependence of hydrogen isotope ratios of leaf wax n-alkanes (δDwax) can be used to estimate paleoaltitudinal changes. However, the application of δDwax-based paleoaltimetry remains difficult, as the impacts of evaporative, transpirative and biosynthetic processes on hydrogen isotope fractionations in changing environments and the influence of likely changing water vapor sources are not well explored. For this study, we sampled stream waters, soils and plant leaves along two transects spanning large gradients of altitude, precipitation amount, vapor source, temperature and vegetation type on the Tibetan Plateau (TP). δD values of stream water (as an approximation for δDp), soil water (δDsw) and plant leaf water (δDlw) as well as leaf wax n-alkanes were measured in order to quantify isotopic fractionations in the formation of leaf waxes. Most interestingly, we found a strong negative correlation between the evapotranspirative enrichment of leaf water against precipitation (εlw-p), which combines the effects of soil evaporation and leaf transpiration, and the biosynthetic hydrogen isotope fractionation (εwax-lw), which describes isotopic enrichment between leaf wax and leaf water. The relationship yields a steady apparent isotopic enrichment factor (εwax-p) between leaf wax and precipitation, which is independent from climatic parameters and has an average value of -107 ± 26‰ for grasses (monocotyledons) and -77 ± 22‰ for trees (dicotyledons). Since the terrestrial n-alkanes, especially n-C27 and n-C29, in sediments are derived from trees and grasses, the likely change of the vegetation type in the uplift of mountains can change the isotopic estimates by about ±30‰, which corresponds to an altitudinal change of ∼1600 m. We, therefore, suggest that hydrogen isotope ratio of sedimentary n-C31 alkane, which is mainly derived from grasses might be better proxies to reconstruct paleoaltitudes. Our large

  9. The Cl-35/Cl-37 isotopic ratio in dense molecular clouds : HIFI observations of hydrogen chloride towards W3 A

    NARCIS (Netherlands)

    Cernicharo, J.; Goicoechea, J. R.; Daniel, F.; Agundez, M.; Caux, E.; de Graauw, T.; De Jonge, A.; Kester, D.; Leduc, H. G.; Steinmetz, E.; Stutzki, J.; Ward, J. S.

    2010-01-01

    We report on the detection with the HIFI instrument on board the Herschel satellite of the two hydrogen chloride isotopologues, (HCl)-Cl-35 and (HCl)-Cl-37, towards the massive star-forming region W3 A. The J = 1-0 line of both species was observed with receiver 1b of the HIFI instrument at similar

  10. South Pacific Convergence Zone Changes during the Late Holocene Identified from Hydrogen Isotope Ratios of Terrestrial and Aquatic Biomarkers from Freshwater Lake Sediments in Vanuatu

    Science.gov (United States)

    Maloney, A. E.; Ladd, N.; Nelson, D. B.; Sachs, J. P.; Dubois, N.

    2017-12-01

    The South Pacific Convergence Zone (SPCZ) is one of Earth's major precipitation features. Mean annual rainfall rates are as high as 10 mm/day in the Solomon Islands in the northwest portion of the SPCZ, and decline to 4 mm/day in portions of French Polynesia the southeastern reach of the SPCZ. Coral records suggest that the mean annual position and precipitation intensity associated with the SPCZ have most likely expanded and contracted on decadal to centennial timescales, but existing data is limited, making it difficult to constrain and characterize these changes. Thion Island (15.03 °S, 167.09 °E) is located off the east coast of Espírito Santo in Vanuatu, at an intermediate position in the modern SPCZ. As such, it should be sensitive to major contractions and expansions of the SPCZ, with wetter conditions when the SPCZ expands southeast, and drier conditions when it contracts to the northwest. In order to determine changes in precipitation over the past millennium on Thion Island, we collected sediment cores from two adjacent freshwater lakes on the island, White Lake and Red Lake, and measured compound specific hydrogen isotope ratios (2H/1H) of lipid biomarkers from terrestrial plants (long-chain n-alkanes and n­-alkanoic acids), aquatic plants (mid-chain n­-alkanes and n-alkanoic acids), and microalgae (dinosterol and botryococcenes). For all measured biomarkers, 2H/1H ratios were higher during the Little Ice Age (LIA, late 14th century to early 19th century) relative to the preceding Medieval Climate Anomaly (MCA) and to the 20th century, suggesting drier conditions at this location during the LIA. The magnitude of decrease in 2H/1H ratios was twice as large for microalgal dinosterol ( 40 ‰ decrease) as for leaf waxes associated with higher plants ( 20 ‰ decrease). The leaf wax data likely reflects changes in precipitation isotopes due to the amount effect, while the microalgal values should change with lake water 2H/1H, which is sensitive to both

  11. Stable carbon and hydrogen isotope analysis of methyl tert-butyl ether and tert-amyl methyl ether by purge and trap-gas chromatography-isotope ratio mass spectrometry: method evaluation and application.

    Science.gov (United States)

    Kujawinski, Dorothea M; Stephan, Manuel; Jochmann, Maik A; Krajenke, Karen; Haas, Joe; Schmidt, Torsten C

    2010-01-01

    In order to monitor the behaviour of contaminants in the aqueous environment effective enrichment techniques often have to be employed due to their low concentrations. In this work a robust and sensitive purge and trap-gas chromatography-isotope ratio mass spectrometry method for carbon and hydrogen isotope analysis of fuel oxygenates in water is presented. The method evaluation included the determination of method detection limits, accuracy and reproducibility of deltaD and delta(13)C values. Lowest concentrations at which reliable delta(13)C values could be determined were 5 microg L(-1) and 28 microg L(-1) for TAME and MTBE, respectively. Stable deltaD values for MTBE and TAME could be achieved for concentrations as low as 25 and 50 microg L(-1). Good long-term reproducibility of delta(13)C and deltaD values was obtained for all target compounds. But deltaD values varying more than 5 per thousand were observed using different thermal conversion tubes. Thus, a correction of deltaD values in the analysis of groundwater samples was necessary to guarantee comparability of the results. The applicability of this method was shown by the analysis of groundwater samples from a gasoline contaminated site. By two dimensional isotope analysis two locations within this site were identified at which anaerobic and aerobic degradation of methyl tert-butyl ether occurred.

  12. Reproducibility of isotope ratio measurements

    International Nuclear Information System (INIS)

    Elmore, D.

    1981-01-01

    The use of an accelerator as part of a mass spectrometer has improved the sensitivity for measuring low levels of long-lived radionuclides by several orders of magnitude. However, the complexity of a large tandem accelerator and beam transport system has made it difficult to match the precision of low energy mass spectrometry. Although uncertainties for accelerator measured isotope ratios as low as 1% have been obtained under favorable conditions, most errors quoted in the literature for natural samples are in the 5 to 20% range. These errors are dominated by statistics and generally the reproducibility is unknown since the samples are only measured once

  13. Process for exchanging hydrogen isotopes between gaseous hydrogen and water

    International Nuclear Information System (INIS)

    Hindin, S. G.; Roberts, G. W.

    1980-01-01

    A process for exchanging isotopes of hydrogen, particularly tritium, between gaseous hydrogen and water is provided whereby gaseous hydrogen depeleted in tritium and liquid or gaseous water containing tritium are reacted in the presence of a metallic catalyst

  14. Catalysed hydrogen isotope exchange

    International Nuclear Information System (INIS)

    1973-01-01

    A method is described for enhancing the rate of exchange of hydrogen atoms in organic compounds or moieties with deuterium or tritium atoms. It comprises reacting the organic compound or moiety and a compound which is the source of deuterium or tritium in the presence of a catalyst consisting of a non-metallic, metallic or organometallic halide of Lewis acid character and which is reactive towards water, hydrogen halides or similar protonic acids. The catalyst is a halide or organometallic halide of: (i) zinc or another element of Group IIb; (ii) boron, aluminium or another element of Group III; (iii) tin, lead, antimony or another element of Groups IV to VI; or (iv) a transition metal, lanthanide or stable actinide; or a halohalide. (author)

  15. Biogeochemistry of the stable hydrogen isotopes

    International Nuclear Information System (INIS)

    Estep, M.F.; Hoering, T.C.

    1980-01-01

    The fractionation of H isotopes between the water in the growth medium and the organically bonded H from microalgae cultured under conditions, where light intensity and wavelength, temperature, nutrient availability, and the H isotope ratio of the water were controlled, is reproducible and light dependent. All studies were based either on the H isotope ratios of the total organic H or on the lipids, where most of the H is firmly bonded to C. H bonded into other macromolecules, proteins, carbohydrates and nucleic acids, does not exchange with water, when algae are incubated in water enriched with deuterium. Only after the destruction of quaternary H bonds are labile hydrogens in macromolecules free to exchange with water. By growing algae (18 strains), including blue-green algae, green algae and diatoms, in continuous light, the isotope fractionations in photosynthesis were reproducibly -93 to -178 per thousand, depending on the organism tested. This fractionation was not temperature dependent. Microalgae grown in total darkness with an organic substrate did not show the isotope fractionation seen in cells grown in light. In both light- and dark-grown algae, however, additional depletion of deuterium (-30 to -60 per thousand) in cellular organic matter occurs during the metabolism of carbohydrates to form lipids. Plants from several natural populations also fractionated isotopes during photosynthesis by an average of -90 to -110 per thousand. In addition, the organically bonded H in nonsaponifiable lipids was further fractionated by -80 per thousand from that in saponifiable lipids, isolated from two geographically distinct populations of marsh plants. This difference between H isotope ratios of these two groups of lipids provides an endogenous isotopic marker. (author)

  16. Biogeochemistry of the stable hydrogen isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Estep, M F; Hoering, T C [Carnegie Institution of Washington, DC (USA)

    1980-08-01

    The fractionation of H isotopes between the water in the growth medium and the organically bonded H from microalgae cultured under conditions, where light intensity and wavelength, temperature, nutrient availability, and the H isotope ratio of the water were controlled, is reproducible and light dependent. All studies were based either on the H isotope ratios of the total organic H or on the lipids, where most of the H is firmly bonded to C. H bonded into other macromolecules, proteins, carbohydrates and nucleic acids, does not exchange with water, when algae are incubated in water enriched with deuterium. Only after the destruction of quaternary H bonds are labile hydrogens in macromolecules free to exchange with water. By growing algae (18 strains), including blue-green algae, green algae and diatoms, in continuous light, the isotope fractionations in photosynthesis were reproducibly -93 to -178 per thousand, depending on the organism tested. This fractionation was not temperature dependent. Microalgae grown in total darkness with an organic substrate did not show the isotope fractionation seen in cells grown in light. In both light- and dark-grown algae, however, additional depletion of deuterium (-30 to -60 per thousand) in cellular organic matter occurs during the metabolism of carbohydrates to form lipids. Plants from several natural populations also fractionated isotopes during photosynthesis by an average of -90 to -110 per thousand. In addition, the organically bonded H in nonsaponifiable lipids was further fractionated by -80 per thousand from that in saponifiable lipids, isolated from two geographically distinct populations of marsh plants. This difference between H isotope ratios of these two groups of lipids provides an endogenous isotopic marker.

  17. Process for exchanging hydrogen isotopes between gaseous hydrogen and water

    International Nuclear Information System (INIS)

    Hindin, S.G.; Roberts, G.W.

    1977-01-01

    A process is described for exchanging isotopes (particularly tritium) between water and gaseous hydrogen. Isotope depleted gaseous hydrogen and water containing a hydrogen isotope are introduced into the vapour phase in a first reaction area. The steam and gaseous hydrogen are brought into contact with a supported metal catalyst in this area in a parallel flow at a temperature range of around 225 and 300 0 C. An effluent flow comprising a mixture of isotope enriched gaseous hydrogen and depleted steam is evacuated from this area and the steam condensed into liquid water [fr

  18. Recent development in isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    Platzner, I.

    1992-01-01

    Within the limited of this review the following topics will be briefly discussed: a) Accuracy, precision, internal relative standard deviation (RISD) and external relative standard deviation (RESD) of isotope ratio measurements. With advanced instrumentation and use of standard reference materials, high accuracy and RESD = 0.002% (or better) may be achieved; b) The advantages of modern automatic isotope ratio mass spectrometer are briefly described. Computer controlled operation and data acquisition, and multiple ion collection are the recent important improvement; c) The isotopic fractionation during the course of isotope ratio measurement is considered as a major source of errors in thermal ionization of metallic elements. The phenomenon in strontium, neodymium, uranium, lead and calcium and methods to correct the measured data are discussed; d) Applications of isotope ratio mass spectrometry in atomic weight determinations, the isotope dilution technique, isotope geology, and isotope effects in biological systems are described together with specific applications in various research and technology area. (author)

  19. Hydrogen isotope fractionation in methane plasma

    Science.gov (United States)

    Robert, François; Derenne, Sylvie; Lombardi, Guillaume; Hassouni, Khaled; Michau, Armelle; Reinhardt, Peter; Duhamel, Rémi; Gonzalez, Adriana; Biron, Kasia

    2017-01-01

    The hydrogen isotope ratio (D/H) is commonly used to reconstruct the chemical processes at the origin of water and organic compounds in the early solar system. On the one hand, the large enrichments in deuterium of the insoluble organic matter (IOM) isolated from the carbonaceous meteorites are interpreted as a heritage of the interstellar medium or resulting from ion-molecule reactions taking place in the diffuse part of the protosolar nebula. On the other hand, the molecular structure of this IOM suggests that organic radicals have played a central role in a gas-phase organosynthesis. So as to reproduce this type of chemistry between organic radicals, experiments based on a microwave plasma of CH4 have been performed. They yielded a black organic residue in which ion microprobe analyses revealed hydrogen isotopic anomalies at a submicrometric spatial resolution. They likely reflect differences in the D/H ratios between the various CHx radicals whose polymerization is at the origin of the IOM. These isotopic heterogeneities, usually referred to as hot and cold spots, are commensurable with those observed in meteorite IOM. As a consequence, the appearance of organic radicals in the ionized regions of the disk surrounding the Sun during its formation may have triggered the formation of organic compounds.

  20. Hydrogen isotope effect through Pd in hydrogen transport pipe

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi

    1992-01-01

    This investigation concerns hydrogen system with hydrogen transport pipes for transportation, purification, isotope separation and storage of hydrogen and its isotopes. A principle of the hydrogen transport pipe (heat pipe having hydrogen transport function) was proposed. It is comprised of the heat pipe and palladium alloy tubes as inlet, outlet, and the separation membrane of hydrogen. The operation was as follows: (1) gas was introduced into the heat pipe through the membrane in the evaporator; (2) the introduced gas was transported toward the condenser by the vapor flow; (3) the transported gas was swept and compressed to the end of the condenser by the vapor pressure; and (4) the compressed gas was exhausted from the heat pipe through the membrane in the condenser. The characteristics of the hydrogen transport pipe were examined for various working conditions. Basic performance concerning transportation, evacuation and compression was experimentally verified. Isotopic dihydrogen gases (H 2 and D 2 ) were used as feed gas for examining the intrinsic performance of the isotope separation by the hydrogen transport pipe. A simulated experiment for hydrogen isotope separation was carried out using a hydrogen-helium gas mixture. The hydrogen transport pipe has a potential for isotope separation and purification of hydrogen, deuterium and tritium in fusion reactor technology. (author)

  1. Treatment and storage of hydrogen isotopes

    International Nuclear Information System (INIS)

    Jung, H. S.; Lee, H. S.; An, D. H.; Kim, K. R.; Lee, S. H.; Choi, H. J.; Back, S. W.; Kang, H. S.; Eom, K. Y.; Lee, M. S.

    2000-01-01

    Storage of gaseous hydrogen isotopes in a cylinder is a well-established technology. However, Immobilization in the solid form is preferred for long-term storage of radioactive isotope gas because of the concern for leakage of the gas. The experimental thermodynamic p-c-T data show that Ti and U soak up hydrogen isotope gas at a temperature of a few hundred .deg. C and modest pressures. It was found that more hydrogen is dissolved in the metal than deuterium at constant pressure. Thus, the lighter isotope tends to be enriched in the solid phase

  2. Isotope exchange reactions in hydrogen mixtures

    International Nuclear Information System (INIS)

    Czaplinski, W.; Gula, A.; Kravtsov, A.; Mikhailov, A.; Popov, N.

    1990-12-01

    The rates of isotopic exchange for the excited states of muonic hydrogen are calculated as functions of collision energy. Ground state population q 1s for different collision energies, target densities and isotope concentrations is obtained. It is shown that for principal quantum numbers n > 5 the isotopic exchange still considerably influences the value of q 1s . (author)

  3. Laser photochemical separation of hydrogen isotopes

    International Nuclear Information System (INIS)

    Fowler, M.C.

    1979-01-01

    A method of separating isotopes of hydrogen utilizing isotopically selective photodissociation of organic acid is disclosed. Specifically acetic or formic acid containing compounds of deuterated nd hydrogenated acid is irradiated by radiation having a wavelength in the infrared spectrum between 9.2 to 10.8 microns to produce deuterium hydroxide and deuterium hydride respectively. Maintaining the acid at an elevated temperature significantly improves the yield of isotope separation

  4. Permeability of hydrogen isotopes through Pd-Ag membrane

    International Nuclear Information System (INIS)

    Yoshida, Hiroshi

    1981-01-01

    This paper represents the permeabilities, diffusion coefficients and isotope effects for hydrogen and deuterium through Pd-25 wt.% Ag alloy tubes The feed gas H 2 or D 2 flowing into the permeation cell was preheated before it reached to the outer surface of the permeation tube made of palladium-silver alloy. Permeation time lag method could be successfully carried out with the present apparatus to measure both permeability and diffusion coefficient. The square-root pressure dependence for the permeation of hydrogen isotopes was observed. The observed systematic temperature dependence indicates that the approximation of the Arrhenius' relation was effective within this experimental conditions. Some tendency of permeation fluxes in relation to the reciprocal temperature, 1/T, was seen. The permeability ratio was larger than the square root of isotopic mass ratio, and it decreased with temperature rise. On the contrary, the diffusion coefficient ratio was much smaller than the square root of isotopic mass ratio. (Kato, T.)

  5. Isotopic ratios in the solar system

    International Nuclear Information System (INIS)

    1985-01-01

    This colloquium is aimed at presentation of isotope ratio measurements in different objects of solar system and surrounding interstellar space and evaluation of what information on composition and structure of primitive solar nebula and on chemical evolution of interstellar space in this part of the galaxy can be deduced from it. Isotope ratio in solar system got from laboratory study of extraterrestrial materials is a subject of this colloquium. Then isotope ratio measured in solar wind, planets and comets. Measurements either are made in-situ by mass spectrometry of ions in solar wind or planetery atmosphere gases either are remote measurements of spectra emitted by giant planets and comets. At last, planetology and astrophysics implications are presented and reviewed. Consraints for solar system formation model can be deduced from isotope ratio measurement. Particularly, isotope anomalies are marks of the processes, which have influenced the primitive solar nebula contraction [fr

  6. Strange Isotope Ratios in Jupiter

    Science.gov (United States)

    Manuel, O.; Ragland, D.; Windler, K.; Zirbel, J.; Johannes, L.; Nolte, A.

    1998-05-01

    At the January AAS meeting, Dr. Daniel Goldin ordered the release of isotopic data from the 1995 Galileo probe into Jupiter. This probe took mass readings for mass numbers 2-150, which includes all of the noble gas isotopes. A certain few noble gas isotopes, specifically those at mass/charge = 21, 40, 78, 124, and 126, are difficult to distinguish from background, while interference causes some variation in signals for noble gas isotopes at mass/charge = 20, 22, 36, 38, 40, 80, 82, 83, 84 and 86. Some contamination was caused by incomplete adsorption of low mass hydrocarbons by Carbosieve, the material used in the concentration cells [Space Sci. Rev. 60, 120 (1992)]. Thus, preliminary results are most reliable in the high mass region that includes xenon. The Galileo Probe provided the first direct measurements from a planet with a chemical composition drastically different from Earth. Our preliminary analyses indicate that Jupiter contains Xe-X [Nature 240, 99 (1972)], which differs significantly from Earth's xenon. Xe-X and primordial He are tightly coupled on the microscopic scale of meteorite minerals [Science 195, 208 (1977); Meteoritics 15, 117 (1980)]. The presence today of Xe-X in the He-rich atmosphere of Jupiter suggests that the primordial linkage of Xe-X with He extended across the protosolar nebula, on a planetary scale [Comments Astrophys. 18, 335 (1997)]. Contamination by hydrocarbons and other gases does not necessarily remove light noble gases from further consideration. Currently, isolation of signals of these elements from interference continues and may result in the presentation of many other interesting observations at the conference.

  7. Process chemistry related to hydrogen isotopes

    International Nuclear Information System (INIS)

    Iwasaki, Matae; Ogata, Yukio

    1991-01-01

    Hydrogen isotopes, that is, protium, deuterium and tritium, are all related deeply to energy in engineering region. Deuterium and tritium exist usually as water in extremely thin state. Accordingly, the improvement of the technology for separating these isotopes is a large engineering subject. Further, tritium is radioactive and its half-life period is 12.26 years, therefore, it is desirable to fix it in more stable form besides its confinement in the handling system. As the chemical forms of hydrogen, the molecular hydrogen with highest reactivity, metal hydride, carbon-hydrogen-halogen system compounds, various inorganic hydrides, most stable water and hydroxides are enumerated. The grasping of the behavior from reaction to stable state of these hydrogen compounds and the related materials is the base of process chemistry. The reaction of exchanging isotopes between water and hydrogen on solid catalyzers, the decomposition of ethane halide containing hydrogen, the behavior of water and hydroxides in silicates are reported. The isotope exchange between water and hydrogen is expected to be developed as the process of separating and concentrating hydrogen isotopes. (K.I.) 103 refs

  8. Sulfur and Hydrogen Isotope Anomalies in Meteorite Sulfonic Acids

    Science.gov (United States)

    Cooper, George W.; Thiemens, Mark H.; Jackson, Teresa L.; Chang, Sherwood

    1997-01-01

    Intramolecular carbon, hydrogen, and sulfur isotope ratios were measured on a homologous series of organic sulfonic acids discovered in the Murchison meteorite. Mass-independent sulfur isotope fractionations were observed along with high deuterium/hydrogen ratios. The deuterium enrichments indicate formation of the hydrocarbon portion of these compounds in a low-temperature environment that is consistent with that of interstellar clouds. Sulfur-33 enrichments observed in methanesulfonic acid could have resulted from gas-phase ultraviolet irradiation of a precursor, carbon disulfide. The source of the sulfonic acid precursors may have been the reactive interstellar molecule carbon monosulfide.

  9. Room temperature Sieving of Hydrogen Isotopes Using 2-D Materials

    Energy Technology Data Exchange (ETDEWEB)

    Hitchcock, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Krentz, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Serkiz, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Velten, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Xiao, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-28

    Hydrogen isotope separation is critical to the DOE’s mission in environmental remediation and nuclear nonproliferation. Isotope separation is also a critical technology for the NNSA, and the ability to perform the separations at room temperature with a relatively small amount of power and space would be a major advancement for their respective missions. Recent work has shown that 2-D materials such as graphene and hexagonal boron nitride can act as an isotopic sieve at room temperature; efficiently separating hydrogen isotopes in water with reported separation ratios of 10:1 for hydrogen: deuterium separation for a single pass. The work performed here suggests that this technique has merit, and furthermore, we are investigating optimization and scale up of the required 2-D material based membranes.

  10. Isotope ratio in stellar atmospheres and nucleosynthesis

    International Nuclear Information System (INIS)

    Barbuy, B.L.S.

    1987-01-01

    The determination of isotopic ratios in stellar atmospheres is studied. The isotopic shift of atomic and molecular lines of different species of a certain element is examined. CH and MgH lines are observed in order to obtain the 12 C: 13 C and 24 Mg: 25 Mg: 26 Mg isotpic ratios. The formation of lines in stellar atmospheres is computed and the resulting synthetic spectra are employed to determine the isotopic abundances. The results obtained for the isotopic ratios are compared to predictions of nucleosynthesis theories. Finally, the concept of primary and secondary element is discussed, and these definitions are applied to the observed variations in the abundance of elements as a function of metallicity. (author) [pt

  11. Calibration and application of lipid hydrogen isotopic ratios for quantitative reconstruction of new england climate variability over the past 15 kyr

    Science.gov (United States)

    Hou, Juzhi

    2009-11-01

    In Chapter 1, I use transects of modern lake surface sediment in eastern North America to demonstrate that the D/H ratios of C22 n-alkanoic acid (deltaDBA), mainly produced by aquatic macrophytes, effectively capture lake water isotopic composition. Downcore variations in deltaDBA values and pollen taxa are highly consistent with the known climate change history of New England. D/H fractionations of long chain even numbered fatty acids (C24-C30 n-acids) relative to lake water provide independent estimates of relative humidity during the growing season. In Chapter 2, I investigate the variability of deltaD values of leaf waxes produced by various terrestrial plants in order to understand the controlling factors of leaf wax deltaD values. The results indicate that inferring precipitation D/H ratios based on sedimentary leaf waxes are only viable when significant vegetation change is absent or can be accounted for isotopically. In addition, the negative correlation between leaf wax deltaD and delta13C values of various trees suggest that plant water-use efficiency exerts an important control on the leaf wax deltaD variation among different tree species. In Chapter 3, the D/H ratios of leaf waxes (deltaDwax) derived from terrestrial plants and preserved in lake sediments have been shown as a reliable proxy for precipitation isotopic variation, especially in relative dry regions. Leaf waxes produced by plants grown under controlled conditions (RH = 80, 60, 40%) show a small increase in D/H ratios as RH decreases, consistent with prediction from the Craig-Gordon model. However, the isotopic effect of RH on deltaDwax along the entire transect is partially countered by the opposing influence of vegetation changes. The correlation between deltaD wax and deltaDP values is significantly higher (R 2 = 0.84) in the drier portions of the transect than in the wetter regions (R2 = 0.64). This study suggests that D/H ratios of sedimentary leaf waxes can be used as a proxy for

  12. Molecular dynamics simulation of hydrogen isotope injection into graphene

    International Nuclear Information System (INIS)

    Nakamura, Hiroaki; Takayama, Arimichi; Ito, Atsushi

    2007-07-01

    We reveal the hydrogen isotope effect of three chemical reactions, i.e., the reflection, the absorption and the penetration ratios, by classical molecular dynamics simulation with a modified Brenner's reactive empirical bond order (REBO) potential. We find that the reflection by π-electron does not depend on the mass of the incident isotope, but the peak of the reflection by nuclear moves to higher side of incident energy. In addition to the reflection, we also find that the absorption ratio in the positive z side of the graphene becomes larger, as the mass of the incident isotope becomes larger. On the other hand, the absorption ratio in the negative z side of the graphene becomes smaller. Last, it is found that the penetration ratio does not depend on the mass of the incident isotope because the graphene potential is not affected by the mass. (author)

  13. Evaluation of the plasma hydrogen isotope content by residual gas analysis at JET and AUG

    Science.gov (United States)

    Drenik, A.; Alegre, D.; Brezinsek, S.; De Castro, A.; Kruezi, U.; Oberkofler, M.; Panjan, M.; Primc, G.; Reichbauer, T.; Resnik, M.; Rohde, V.; Seibt, M.; Schneider, P. A.; Wauters, T.; Zaplotnik, R.; ASDEX-Upgrade, the; EUROfusion MST1 Teams; contributors, JET

    2017-12-01

    The isotope content of the plasma reflects on the dynamics of isotope changeover experiments, efficiency of wall conditioning and the performance of a fusion device in the active phase of operation. The assessment of the isotope ratio of hydrogen and methane molecules is used as a novel method of assessing the plasma isotope ratios at JET and ASDEX-Upgrade (AUG). The isotope ratios of both molecules in general shows similar trends as the isotope ratio detected by other diagnostics. At JET, the absolute values of RGA signals are in relatively good agreement with each other and with spectroscopy data, while at AUG the deviation from neutral particle analyser data are larger, and the results show a consistent spatial distribution of the isotope ratio. It is further shown that the isotope ratio of the hydrogen molecule can be used to study the degree of dissociation of the injected gas during changeover experiments.

  14. Uranium isotope ratio measurements in field settings

    International Nuclear Information System (INIS)

    Shaw, R.W.; Barshick, C.M.; Young, J.P.; Ramsey, J.M.

    1997-01-01

    The authors have developed a technique for uranium isotope ratio measurements of powder samples in field settings. Such a method will be invaluable for environmental studies, radioactive waste operations, and decommissioning and decontamination operations. Immediate field data can help guide an ongoing sampling campaign. The measurement encompasses glow discharge sputtering from pressed sample hollow cathodes, high resolution laser spectroscopy using conveniently tunable diode lasers, and optogalvanic detection. At 10% 235 U enrichment and above, the measurement precision for 235 U/( 235 U+ 238 U) isotope ratios was ±3%; it declined to ±15% for 0.3% (i.e., depleted) samples. A prototype instrument was constructed and is described

  15. Stable isotope ratios in hair and teeth reflect biologic rhythms.

    Directory of Open Access Journals (Sweden)

    Otto Appenzeller

    Full Text Available Biologic rhythms give insight into normal physiology and disease. They can be used as biomarkers for neuronal degenerations. We present a diverse data set to show that hair and teeth contain an extended record of biologic rhythms, and that analysis of these tissues could yield signals of neurodegenerations. We examined hair from mummified humans from South America, extinct mammals and modern animals and people, both healthy and diseased, and teeth of hominins. We also monitored heart-rate variability, a measure of a biologic rhythm, in some living subjects and analyzed it using power spectra. The samples were examined to determine variations in stable isotope ratios along the length of the hair and across growth-lines of the enamel in teeth. We found recurring circa-annual periods of slow and fast rhythms in hydrogen isotope ratios in hair and carbon and oxygen isotope ratios in teeth. The power spectra contained slow and fast frequency power, matching, in terms of normalized frequency, the spectra of heart rate variability found in our living subjects. Analysis of the power spectra of hydrogen isotope ratios in hair from a patient with neurodegeneration revealed the same spectral features seen in the patient's heart-rate variability. Our study shows that spectral analysis of stable isotope ratios in readily available tissues such as hair could become a powerful diagnostic tool when effective treatments and neuroprotective drugs for neurodegenerative diseases become available. It also suggests that similar analyses of archaeological specimens could give insight into the physiology of ancient people and animals.

  16. Application of gas chromatography in hydrogen isotope separation

    International Nuclear Information System (INIS)

    Ye Xiaoqiu; Sang Ge; Peng Lixia; Xue Yan; Cao Wei

    2008-01-01

    The principle of gas chromatographic separation of hydrogen isotopes was briefly introduced. The main technology and their development of separating hydrogen isotopes, including elution chromatography, hydrogen-displacement chromatography, self-displacement chromatography and frontal chromatography were discussed in detail. The prospect of hydrogen isotope separation by gas chromatography was presented. (authors)

  17. Plutonium isotope ratios in polychaete worms

    International Nuclear Information System (INIS)

    Beasley, T.M.; Fowler, S.W.

    1976-01-01

    Reference is made to recent reports that suggest that terrestrial and aquatic organisms may preferentially take up 238 Pu compared with sup(239+240)Pu. It is stated that although kinetic isotope effects are known to occur in biological systems for low mass number elements, such as H, C and N, such effects are generally discounted with higher mass numbers, and differences in the biological 'uptake' of isotopes of high mass number elements, such as those of Pu, are normally attributable to differences in the chemical or physical forms of the isotopes or to different quantities of isotopes available to organisms. This has been applied to explain differential Pu isotope behaviour in animals under controlled laboratory conditions, but it is not certain that it can be applied to explain anomalies of Pu isotope behaviour in organisms contaminated by nuclear test debris or by wastes from nuclear fuel reprocessing plants. Geochemical weathering may also have an effect. Described here are experiments in which it was found that deposit feeding marine worms living in sediments contaminated in different ways with Pu isotopes did not show preferential accumulation of 238 Pu. The worms had been exposed to different chemical and physical forms of the isotopes, including exposure to laboratory-labelled sediment, sediment collected from a former weapons test site, and sediment contaminated by wastes from a nuclear fuel reprocessing plant. The worms were allowed to accumulate Pu for times of 5 to 40 days. Isotope ratios were determined by α-spectrometric techniques. It is considered that the results are important for environmental samples where Pu activity levels are low. (U.K.)

  18. H/D Isotope Effects in Hydrogen Bonded Systems

    Directory of Open Access Journals (Sweden)

    Aleksander Filarowski

    2013-04-01

    Full Text Available An extremely strong H/D isotope effect observed in hydrogen bonded A-H…B systems is connected with a reach diversity of the potential shape for the proton/deuteron motion. It is connected with the anharmonicity of the proton/deuteron vibrations and of the tunneling effect, particularly in cases of short bridges with low barrier for protonic and deuteronic jumping. Six extreme shapes of the proton motion are presented starting from the state without possibility of the proton transfer up to the state with a full ionization. The manifestations of the H/D isotope effect are best reflected in the infra-red absorption spectra. A most characteristic is the run of the relationship between the isotopic ratio nH/nD and position of the absorption band shown by using the example of NHN hydrogen bonds. One can distinguish a critical range of correlation when the isotopic ratio reaches the value of ca. 1 and then increases up to unusual values higher than . The critical range of the isotope effect is also visible in NQR and NMR spectra. In the critical region one observes a stepwise change of the NQR frequency reaching 1.1 MHz. In the case of NMR, the maximal isotope effect is reflected on the curve presenting the dependence of Δd (1H,2H on d (1H. This effect corresponds to the range of maximum on the correlation curve between dH and ΔpKa that is observed in various systems. There is a lack in the literature of quantitative information about the influence of isotopic substitution on the dielectric properties of hydrogen bond except the isotope effect on the ferroelectric phase transition in some hydrogen bonded crystals.

  19. Hydrogen isotope separation by cryogenic distillation method

    International Nuclear Information System (INIS)

    Hayakawa, Nobuo; Mitsui, Jin

    1987-01-01

    Hydrogen isotope separation in fusion fuel cycle and tritium recovery from heavy water reactor are very important, and therefore the early establishment of these separation techniques are desired. The cryogenic distillation method in particular is promising for the separation of hydrogen isotope and the recovery of high concentrated tritium. The studies of hydrogen isotope separation by cryogenic distillation method have been carried out by using the experimental apparatus made for the first time in Japan. The separation of three components (H 2 -HD-D 2 ) under total reflux conditions was got by using the packing tower of 500 mm height. It was confirmed that the Height Equivalent Theoretical Plate (HETP) was 20 - 30 mm for the vapor's line velocity of 20 - 80 mm/s. (author)

  20. Effect Of Substrates On The Fractionation Of Hydrogen Isotopes During Lipid-Biosynthesis By Haloarcula marismortui

    Science.gov (United States)

    Dirghangi, S. S.; Pagani, M.

    2010-12-01

    Lipids form an important class of proxies for paleoclimatological research, and hydrogen isotope ratios of lipids are being increasingly used for understanding changes in the hydrological system. Proper understanding of hydrogen isotope fractionation during lipid biosynthesis is therefore important and attention has been directed toward understanding the magnitude of hydrogen isotope fractionation that occurs during lipid biosynthesis in various organisms. Hydrogen isotope ratios of lipids depend on the hydrogen isotopic composition of the ambient water, hydrogen isotopic composition of NADPH used during biosynthesis, growth conditions, pathways of lipid biosynthesis, and substrates in the case of heterotrophic organisms. Recently it has been observed that NADPH contributes a significant part of the hydrogen in fatty acids synthesized by bacteria during heterotrophic growth (Zhang et al, 2009). As NADPH is formed by reduction of NADP+ during metabolism of substrates, different metabolic pathways form NADPH with different D/H ratios, which in turn results in variation in D/H ratios of lipids (Zhang et al, 2009). Therefore, substrates play a significant role in hydrogen isotopic compositions of lipids. For this study, we are investigating the effects of substrates on hydrogen isotope fractionation during biosynthesis of isoprenoidal lipids by heterotrophically growing halophilic archaea. Haloarcula marismortui is a halophilic archaea which synthesizes Archaeol (a diether lipid) and other isoprenoidal lipids. We have grown Haloarcula marismortui in pure cultures on three different substrates and are in the process of evaluating isotopic variability of Archaeol and other lipids associated with substrate and the D/H composition of ambient water. Our results will be helpful for a better understanding of hydrogen isotope fractionations during lipid synthesis by archaea. Also, halophilic archaea are the only source of archaeol in hypersaline environments. Therefore, our

  1. The hydrogen isotopic composition of kaolin minerals in Japan

    International Nuclear Information System (INIS)

    Marumo, Katsumi; Nagasawa, Keinosuke; Kuroda, Yoshimasu.

    1979-01-01

    Hydrogen isotopic composition (D/H ratio) was determined for kaolin minerals from geothermal areas and sedimentary and hydrothermal kaolin deposits in Japan. On the Ohnuma, Matsukawa, and Ohtake geothermal areas, the hydrogen isotopic fractionation factor between kaolin minerals and water was calculated to fall between 0.97 and 0.99 for the temperature range of 50 to 200 0 C, a fact which shows that the temperature of formation has no important effect on the D/H ratio of kaolin minerals. D/H ratio of kaolinites and dickites from many kaolin deposits shows local variation, and seems to correlate with isotopic variation of the present-day meteoric surface water. Exceptions are seen in some kaolin deposits such as Shokozan, Hiroshima Prefecture, where kaolinite and dickite have considerably high values of D/H ratio, and seem to have reacted with water rich in deuterium. D/H ratio of halloysite is not correlated with that of the present-day meteoric surface water. As Lawrence and Taylor (1971) pointed out, the original D/H ratio of constitutional water of halloysite is not preserved because of the isotopic exchange between the interlayer water and the constitutional water. (author)

  2. New mass spectrometers for hydrogen isotope analyses

    International Nuclear Information System (INIS)

    Chastagner, P.; Daves, H.L.; Hess, W.B.

    1981-01-01

    Two advanced mass spectrometers for the accurate analysis of mixtures of the hydrogen isotopes are being evaluated by Du Pont personnel at the Savannah River Laboratory. One is a large double-focusing instrument with a resolution of 2000 at mass 4, an abundance sensitivity of > 100,000 for the HT-D 2 doublet, and a sophisticated electronic control and data collection system. The second is a smaller, simpler, stigmatic-focusing instrument in which exceptionally high ion intensities (> 1 x 10 -9 A) result in high signal to noise ratios. A containment facility with sample inlet systems and a standard distribution system was built to permit testing with tritium mixtures. The characteristics of the mass spectrometers under a variety of operating conditions will be presented. Factors to be discussed include: sample equilibration and its elimination; linearity; trimer formation; gas interference; stability; signal to noise ratio; mass discrimination; and anticipated precision and accu sublimed molybdenum collector of Converter No. 262; and (3) demonstration of tungsten CVD onto molybdenum flange using a reuseable graphite mandrel

  3. Hydrogen isotope permeation in elastomeric materials

    International Nuclear Information System (INIS)

    Steinmeyer, R.H.; Braun, J.D.

    1976-01-01

    The permeabilities of elastomeric and polymeric materials to hydrogen isotopes were measured at room temperature. The technique for measuring permeation rates is based on the following constant-volume method: a fixed pressure of gas is applied to one side of the specimen to be studied and the permeability constant is determined from the observed rate of pressure increase in an initially evacuated volume on the other side of the specimen. Permeability constants for hydrogen, deuterium, and tritium were measured for Mylar, Teflon, Kapton, Saran, Buna-N, and latex rubber. Results were compared with literature values for hydrogen and deuterium where available and showed excellent agreement

  4. Thermomagnetic torque in hydrogen isotopes

    International Nuclear Information System (INIS)

    Cramer, J.A.

    1975-01-01

    The thermomagnetic torque has been measured in parahydrogen and ortho and normal deuterium for pressures from 0.10 to 2.0 torr and temperatures from 100 to 370 K. Since the torque depends on the precession of the molecular rotational magnetic moment around the field direction, coupling of the molecular nuclear spin to the rotational moment can affect the torque. Evidence of spin coupling effects is found for the torque in both deuterium modifications. In para hydrogen the torque at all temperatures and pressures exhibits behavior expected of a gas of zero nuclear spin molecules. Additionally, earlier data for hydrogen deuteride and for normal hydrogen from 105 to 374 K are evaluated and discussed. The high pressure limiting values of torque peak heights and positions for all these gases are compared with theory

  5. Method of eliminating gaseous hydrogen isotopes

    International Nuclear Information System (INIS)

    Nagakura, Masaaki; Imaizumi, Hideki; Suemori, Nobuo; Aizawa, Takashi; Naito, Taisei.

    1983-01-01

    Purpose: To prevent external diffusion of gaseous hydrogen isotopes such as tritium or the like upon occurrence of tritium leakage accident in a thermonuclear reactor by recovering to eliminate the isotopes rapidly and with safety. Method: Gases at the region of a reactor container where hydrogen isotopes might leak are sucked by a recycing pump, dehumidified in a dehumidifier and then recycled from a preheater through a catalytic oxidation reactor to a water absorption tower. In this structure, the dehumidifier is disposed at the upstream of the catalytic oxidation reactor to reduce the water content of the gases to be processed, whereby the eliminating efficiency for the gases to be processed can be maintained well even when the oxidation reactor is operated at a low temperature condition near the ambient temperature. This method is based on the fact that the oxidating reactivity of the catalyst can be improved significantly by eliminating the water content in the gases to be processed. (Yoshino, Y.)

  6. Measuring hydrogen-isotope distribution profiles

    International Nuclear Information System (INIS)

    Poppe, C.H.

    1977-01-01

    A new nondestructive technique was developed for measuring the depth distribution of hydrogen isotopes absorbed or implanted near the surface of any material. The method allows real-time study of the inventory and diffusion of hydrogen, deuterium, and tritium. Briefly, the technique involves bombarding the surface with a monoenergetic beam of ions chosen for their ability to react with the hydrogen isotope in question and produce fast neutrons. The energy distribution of the neutrons is a sensitive indicator of the energy of the bombarding particles at the instant of reaction, and hence of the depth of the reaction sites below he surface of the material. A sensitivity of one part per million was obtained for tritium in copper. The technique is applicable to several energy-related materials problems. 5 figures

  7. Accurate isotope ratio mass spectrometry. Some problems and possibilities

    International Nuclear Information System (INIS)

    Bievre, P. de

    1978-01-01

    The review includes reference to 190 papers, mainly published during the last 10 years. It covers the following: important factors in accurate isotope ratio measurements (precision and accuracy of isotope ratio measurements -exemplified by determinations of 235 U/ 238 U and of other elements including 239 Pu/ 240 Pu; isotope fractionation -exemplified by curves for Rb, U); applications (atomic weights); the Oklo natural nuclear reactor (discovered by UF 6 mass spectrometry at Pierrelatte); nuclear and other constants; isotope ratio measurements in nuclear geology and isotope cosmology - accurate age determination; isotope ratio measurements on very small samples - archaeometry; isotope dilution; miscellaneous applications; and future prospects. (U.K.)

  8. Significance of Isotopically Labile Organic Hydrogen in Thermal Maturation of Organic Matter

    Energy Technology Data Exchange (ETDEWEB)

    Arndt Schimmelmann; Maria Mastalerz

    2010-03-30

    Isotopically labile organic hydrogen in fossil fuels occupies chemical positions that participate in isotopic exchange and in chemical reactions during thermal maturation from kerogen to bitumen, oil and gas. Carbon-bound organic hydrogen is isotopically far less exchangeable than hydrogen bound to nitrogen, oxygen, or sulfur. We explore why organic hydrogen isotope ratios express a relationship with organic nitrogen isotope ratios in kerogen at low to moderate maturity. We develop and apply new techniques to utilize organic D/H ratios in organic matter fractions and on a molecular level as tools for exploration for fossil fuels and for paleoenvironmental research. The scope of our samples includes naturally and artificially matured substrates, such as coal, shale, oil and gas.

  9. Co-deposition of palladium with hydrogen isotopes

    International Nuclear Information System (INIS)

    Dash, J.; Ambadkar, A.

    2006-01-01

    Palladium was co-deposited with hydrogen isotopes on a Pd cathode. This resulted in enhanced production of excess thermal power. After electrolysis the Pd Lβ/ Lα ratio was found to be increased in characteristic X-ray spectra from localized, microscopic areas on the surface of the Pd cathode. This suggests the possibility that appreciable amounts of silver are present in these areas. (authors)

  10. Raman scattering method and apparatus for measuring isotope ratios and isotopic abundances

    International Nuclear Information System (INIS)

    Harney, R.C.; Bloom, S.D.

    1978-01-01

    Raman scattering is used to measure isotope ratios and/or isotopic abundances. A beam of quasi-monochromatic photons is directed onto the sample to be analyzed, and the resulting Raman-scattered photons are detected and counted for each isotopic species of interest. These photon counts are treated mathematically to yield the desired isotope ratios or isotopic abundances

  11. Critical overview on water - hydrogen isotopic exchange; a case study

    International Nuclear Information System (INIS)

    Peculea, Marius

    2002-01-01

    Water - hydrogen isotopic exchange process is attractive due to its high separation factor; it is neither corrosive or pollutant and, when used as a technological process of heavy water production, it requires water as raw material. Its efficiency depends strongly on the catalyst performance and geometry of the isotopic water - hydrogen exchange zone in which the isotopic transfer proceeds in two steps: liquid vapor distillation in the presence of an inert gas and a catalytic reaction in vapor - gas gaseous phase. An overview of the water hydrogen isotopic exchange is presented and technological details of the Trail - Canada facility as well as characteristics of the two pilots operated in Romania with Ni, Cr and hydrophobic catalysts are described. The mathematical approach of the successive water-water vapor-hydrogen isotopic exchange process given is based on a mathematical model worked out earlier by Palibroda. Discrepancies between computation and experimental results, lower than 11% for extreme cases and around 6% for the average range are explained as due to the ratio of the exchange potentials. Assumption is made in the theoretical approach that this ratio is positive and constant all long the column while the measurements showed that it varies within 0.7 and 1.1 at the upper end and within - 2.5 and - 4.4 at the lower end, what indicates a strong end effect. In conclusion it is stressed that a competing technological solution is emerging based on a monothermal electrolytic process or a bithermal - bibaric process both for heavy water and tritium separation process

  12. Isotopic ratio method for determining uranium contamination

    International Nuclear Information System (INIS)

    Miles, R.E.; Sieben, A.K.

    1994-01-01

    The presence of high concentrations of uranium in the subsurface can be attributed either to contamination from uranium processing activities or to naturally occurring uranium. A mathematical method has been employed to evaluate the isotope ratios from subsurface soils at the Rocky Flats Nuclear Weapons Plant (RFP) and demonstrates conclusively that the soil contains uranium from a natural source and has not been contaminated with enriched uranium resulting from RFP releases. This paper describes the method used in this determination which has widespread application in site characterizations and can be adapted to other radioisotopes used in manufacturing industries. The determination of radioisotope source can lead to a reduction of the remediation effort

  13. Hydrogen isotope fractionation in methane plasma

    OpenAIRE

    Robert, François; Derenne, Sylvie; Lombardi, Guillaume; Hassouni, Khaled; Michau, Armelle; Reinhardt, Peter; Duhamel, Rémi; Gonzalez, Adriana; Biron, Kasia

    2017-01-01

    Large variations in light element isotope ratios (H, N, C) are routinely observed in meteorite organic matter. The origin of these so-called anomalies is not accounted for by the classical theory of isotope fractionation. In the case of H, micrometer-size areas within the insoluble organic matter (IOM) isolated from meteorites by acid treatment, exhibit extreme deuterium enrichment. They are generally interpreted as components exogenous to the solar system and attributed to surviving interste...

  14. Hydrogen isotope analysis by quadrupole mass spectrometry

    International Nuclear Information System (INIS)

    Ellefson, R.E.; Moddeman, W.E.; Dylla, H.F.

    1981-03-01

    The analysis of isotopes of hydrogen (H, D, T) and helium ( 3 He, 4 He) and selected impurities using a quadrupole mass spectrometer (QMS) has been investigated as a method of measuring the purity of tritium gas for injection into the Tokamak Fusion Test Reactor (TFTR). A QMS was used at low resolution, m/Δm 3 He, and 4 He in HT/D 2

  15. Oxygen isotope ratios of the Icelandic crust

    International Nuclear Information System (INIS)

    Hattori, K.; Muehlenbachs, K.

    1982-01-01

    Oxygen isotope ratios of hydrothermally altered basalts from depth of up to approx.3 km are reported from three localities in Iceland: International Research Drilling Project (IRDP) core at Reydarfjordur, eastern Iceland (Tertiary age); drill cuttings from Reykjavik (Plio-Pleistocene age); and Halocene drill cuttings from the active Krafla central volcano. Whole rock samples from these three localities have delta 18 O values averaging +3.9 +- 1.3, +2.4 +- 1.1, and -7.7 +- 2.4%, respectively. The observed values in the deeper samples from Krafla are as low as the values for any rocks previously reported. There seems to be a slight negative gradient in delta 18 O with depth at the former two localities and a more pronounced one at Krafla. Oxygen isotope fractionations between epidote and quartz and those between calcite and fluid suggests that the basalts were altered at temperatures of 300 0 --400 0 C. Low deltaD and delta 18 O of epidote and low delta 34 S of anhydrite indicate that the altering fluids in all three areas originated as meteoric waters and have undergone varied 'oxygen shifts'. Differences in the 18 O shift of the fluids are attributed to differences in hydrothermal systems; low water/rock ratios ( 5) at Krafla. The convective hydrothermal activity, which is probably driven by silicic magma beneath the central volcanoes, has caused strong subsolidus depletion of 18 O in the rocks. The primary-magnetic delta 18 O value of the rocks in the Tertiary IRDP core was about +3.9%, which is lower than that obtained for fresh basalt from other places. Such exceptionally low delta 18 O magmas are common in Iceland and may occur as the result of oxygen isotope exchange with or assimilation of altered rocks that form a thick sequence beneath the island due to isostatic subsidence

  16. Carbon isotope ratios of atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Sakai, Hitoshi; Kishima, Noriaki; Tsutaki, Yasuhiro.

    1982-01-01

    The delta 13 C values relative to PDB were measured for carbon dioxide in air samples collected at various parts of Japan and at Mauna Loa Observatory, Hawaii in the periods of 1977 and 1978. The delta 13 C values of the ''clean air'' are -7.6 % at Hawaii and -8.1 per mille Oki and Hachijo-jima islands. These values are definitely lighter than the carbon isotope ratios (-6.9 per mille) obtained by Keeling for clean airs collected at Southern California in 1955 to 1956. The increase in 12 C in atmospheric carbon dioxide is attributed to the input of the anthropogenic light carbon dioxides (combustion of fossil fuels etc.) Taking -7.6 per mille to be the isotope ratio of CO 2 in the present clean air, a simple three box model predicts that the biosphere has decreased rather than increased since 1955, implying that it is acting as the doner of carbon rather than the sink. (author)

  17. Hydrogen isotope separation for fusion power applications

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R., E-mail: robert.smith@ccfe.ac.uk [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Whittaker, D.A.J.; Butler, B.; Hollingsworth, A.; Lawless, R.E.; Lefebvre, X.; Medley, S.A.; Parracho, A.I.; Wakeling, B. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2015-10-05

    Highlights: • Summary of the tritium plant, the Active Gas Handling System (AGHS), at JET. • Review of the Water Detritiation System (WDS) under construction. • Design of the new Material Detritiation Facility (MDF). • Review of problems in fusion related to metal/hydrogen system. - Abstract: The invited talk given at MH2014 in Salford ranged over many issues associated with hydrogen isotope separation, fusion machines and the hydrogen/metal systems found in the Joint European Torus (JET) machine located near Oxford. As this sort of talk does not lend itself well to a paper below I have attempted to highlight some of the more pertinent information. After a description of the Active Gas Handling System (AGHS) a brief summary of isotope separation systems is described followed by descriptions of three major projects currently being undertaken by the Tritium Engineering and Science Group (TESG), the upgrade to the Analytical Systems (AN-GC) at the AGH, the construction of a Water Detritiation System (WDS) and a Material Detritiation Facility (MDF). Finally, a review of some of the challenges facing fusion with respect to metal/hydrogen systems is presented.

  18. A Hydrogen and He Isotope Nanoprobe

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Barney L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Van Deusen, Stuart B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    Materials that incorporate hydrogen and helium isotopes are of great interest at Sandia and throughout the NNSA and DOE. The Ion Beam Lab at SNL-NM has invented techniques using micron to mm-size MeV ion beams to recoil these light isotopes (Elastic Recoil Detection or ERD) that can very accurately make such measurements. However, there are many measurements that would benefit NW and DOE that require much better resolution, such as the distribution of H isotopes (and 3He) in individual grains of materials relevant to TPBARs, H and He-embrittlement of weapon components important to Tritium Sustainment Programs, issues with GTSs, batteries… Higher resolution would also benefit the field of materials science in general. To address these and many other issues, nm-scale lateral resolution is required. This LDRD demonstrated that neutral H atoms could be recoiled through a thin film by 70 keV electrons and detected with a Channeltron electron multiplier (CEM). The electrons were steered away from the CEM by strong permanent magnets. This proved the feasibility that the high energy electrons from a transmissionelectron- microscope-TEM can potentially be used to recoil and subsequently detect (e-ERD), quantify and map the concentration of H and He isotopes with nm resolution. This discovery could lead to a TEM-based H/He-isotope nanoprobe with 1000x higher resolution than currently available.

  19. How the oxygen isotope ratio of rain water influences the isotope ratio of chicken eggshell carbonate

    Science.gov (United States)

    Price, Gregory; Grimes, Stephen

    2015-04-01

    The stable oxygen isotope ratio of chicken eggshell carbonate was analysed from chicken eggs laid under free range, and organic farming regimes from across the UK. The eggshell carbonate oxygen isotope data shows a clear depletion in delta18O distribution from the southwest to the northeast. Although consistently offset by around 1 permil, the same isotopic distribution as that seen in eggshell carbonate is observed in the delta18O ratio of rainfall and groundwater from across the UK. This distribution is related to the Rayleigh distillation of rainfall driven by westerly winds across the UK landmass. The clear relationship observed between eggshell delta18O values and that of rainwater presumably reflects the nature of free range chickens which must be drinking locally derived rainwater and supplementing their diet and water intake with locally derived food. These results suggest that the oxygen isotope value of chicken eggshells can be used as a forensic tool to identify the locality that free range and organic eggs were laid within the UK. Furthermore, if suitable material is preserved in the archaeological and geological record then such a relationship can potentially be used to establish the oxygen isotope value of rainwater from which ancient and / or ancestral birds lived.

  20. Worldwide lead-isotope ratio in bivalves and sediments

    DEFF Research Database (Denmark)

    Larsen, Martin Mørk; Jacobsen, Gitte; Strand, Jakob

    The lead-isotope ratio have been used to assess and identify impact of leaded gasoline, coal combustion and  mineral activities[ref 1] due to the difference in 206Pb (~52%), 207Pb (~24%) and 208Pb (~23%) isotope ratios. The source of these differences is the decaying of the parent isotopes of 238U...

  1. Kinetics of the excited muonic hydrogen in the mixtures of hydrogen isotopes in helium

    International Nuclear Information System (INIS)

    Bystritskij, V.M.; Kravtsov, A.V.; Popov, N.P.

    1989-01-01

    De-excitation of the excited muonic hydrogen in the mixture of hydrogen isotopes and helium is considered. The method is proposed which allows one to determine the rates of the muon transfer from the excited muonic hydrogen to helium nuclei, as well as the probability of the direct muon atomic capture by nuclei of hydrogen isotopes. 20 refs.; 4 figs

  2. Hydrogen isotope exchange in metal hydride columns

    International Nuclear Information System (INIS)

    Wiswall, R.; Reilly, J.; Bloch, F.; Wirsing, E.

    1977-01-01

    Several metal hydrides were shown to act as chromatographic media for hydrogen isotopes. The procedure was to equilibrate a column of hydride with flowing hydrogen, inject a small quantity of tritium tracer, and observe its elution behavior. Characteristic retention times were found. From these and the extent of widening of the tritium band, the heights equivalent to a theoretical plate could be calculated. Values of around 1 cm were obtained. The following are the metals whose hydrides were studied, together with the temperature ranges in which chromatographic behavior was observed: vanadium, 0 to 70 0 C; zirconium, 500 to 600 0 C; LaNi 5 , -78 to +30 0 C; Mg 2 Ni, 300 to 375 0 C; palladium, 0 to 70 0 C. A dual-temperature isotope separation process based on hydride chromatography was demonstrated. In this, a column was caused to cycle between two temperatures while being supplied with a constant stream of tritium-traced hydrogen. Each half-cycle was continued until ''breakthrough,'' i.e., until the tritium concentration in the effluent was the same as that in the feed. Up to that point, the effluent was enriched or depleted in tritium, by up to 20%

  3. Hydrogen-water isotopic exchange process

    International Nuclear Information System (INIS)

    Cheung, H.

    1984-01-01

    The objects of this invention are achieved by a dual temperature isotopic exchange process employing hydrogen-water exchange with water passing in a closed recirculation loop between a catalyst-containing cold tower and the upper portion of a catalyst-containing hot tower, with feed water being introduced to the lower portion of the hot tower and being maintained out of contact with the water recirculating in the closed loop. Undue retarding of catalyst activity during deuterium concentration can thus be avoided. The cold tower and the upper portion of the hot tower can be operated with relatively expensive catalyst material of higher catalyst activity, while the lower portion of the hot tower can be operated with a relatively less expensive, more rugged catalyst material of lesser catalyst activity. The feed water stream, being restricted solely to the lower portion of the hot tower, requires minimal pretreatment for the removal of potential catalyst contaminants. The catalyst materials are desirably coated with a hydrophobic treating material so as to be substantially inaccessible to liquid water, thereby retarding catalyst fouling while being accessible to the gas for enhancing isotopic exchange between hydrogen gas and water vapor. A portion of the water of the closed loop can be passed to a humidification zone to heat and humidify the circulating hydrogen gas and then returned to the closed loop

  4. ICP-MS for isotope ratio measurement

    Science.gov (United States)

    The use of stable isotopes in mineral nutrition research has become a fundamental aspect of conducting this research. A gradual transition has occurred, now virtually complete, from radioactive isotope studies to those using stable isotopes. Although primarily used in human research, mineral stable ...

  5. Water-hydrogen isotope exchange process analysis

    International Nuclear Information System (INIS)

    Fedorchenko, O.; Alekseev, I.; Uborsky, V.

    2008-01-01

    The use of a numerical method is needed to find a solution to the equation system describing a general case of heterogeneous isotope exchange between gaseous hydrogen and liquid water in a column. A computer model of the column merely outputting the isotope compositions in the flows leaving the column, like the experimental column itself, is a 'black box' to a certain extent: the solution is not transparent and occasionally not fully comprehended. The approximate analytical solution was derived from the ZXY-diagram (McCabe-Thiele diagram), which illustrates the solution of the renewed computer model called 'EVIO-4.2' Several 'unusual' results and dependences have been analyzed and explained. (authors)

  6. Study on influencing factors for hydrogen isotopic exchange

    International Nuclear Information System (INIS)

    Gu Mei; Liu Jun; Luo Yangming

    2013-01-01

    Background: Hydrogen-water catalytic exchange reaction offers an approach to hydrogen isotope separation, which can be applied in heavy water detritiation. Purpose: To optimize the operating condition for hydrogen-water catalytic exchange reaction, we analysed the influence of different factors on the transfer coefficient. Methods: In detail, the isotope exchange experiments of H-D system were carried out in a self-designed catalytic bed loaded with hydrophobic catalyst and hydrophilic packing with certain volume ratio. The experiments showed the changes of both the transfer coefficient and the pressure drop of column with the changing of the operational temperatures (29℃, 45℃, 60℃ and 75℃), the ratios of gas to liquid (0.58, 1.17, 2.65, 3.54) and the deuterium concentrations (5.05×10 -3 , 1.0144×10 -2 , 2.01×10 -2 ). Results: Results showed that 45℃ is the optimal temperature for operating. The transfer coefficient increases with the increasing of the ratio of gas to liquid in the ranges of 0.58 to 1.17 and 2.65 to 3.56, while decreases with the deuterium concentration increases from 5.05×10 -3 to 2.01×10 -2 . The pressure drop of column increases with increasing of gas flow rate. Conclusions: The experiment proves that the ratio of gas to liquid, the reaction temperature and the deuterium concentration are all important factors, which influence the transfer coefficient of deuterium obviously. The optimal operating condition for hydrogen-water catalytic exchange reaction are as follows: the temperature is 45℃, the ratio of gas to liquid is 3.56, and the deuterium concentration is 2.01×10 -2 . (authors)

  7. Impact analysis of a hydrogen isotopes container

    International Nuclear Information System (INIS)

    Lee, M. S.; Hwang, C. S.; Jeong, H. S.

    2003-01-01

    The container used for the radioactive materials, containing hydrogen isotopes is evaluated in a view of hypothetical accident. The computational analysis is a cost effective tool to minimize testing and streamline the regulatory procedures, and supports experimental programs to qualify the container for the safe transport of radioactive materials. The numerical analysis of 9m free-drop onto a flat unyielding, horizontal surface has been performed using the explicit finite element computer program ABAQUS. Especially free-drop simulations for 30 .deg. C tilted condition are precisely estimated

  8. Dynamic simulation of hydrogen isotope distillation unit

    International Nuclear Information System (INIS)

    Le Lann, J.M.; Latge, C.; Joulia, X.; Sere-Peyrigain, P.

    1995-01-01

    Dynamic simulation of hydrogen isotope distillation unit involved in the complex environment of a fusion power plant can be a powerful technique in view to analyze the tritium hazard potential. In this paper, issues related to the development of such a dynamic simulator with model formulation and the numerical treatment of the resulting Differential-Algebraic equation (DAE) system are properly adressed. The typical dynamic characteristics of such columns are quantitatively and qualitatively enlighted on case study with very large disturbances. The developed system has proven to be beneficial for understanding the dynamic behaviour and further for developing control schemes. (orig.)

  9. Dynamic simulation of hydrogen isotope distillation unit

    International Nuclear Information System (INIS)

    Le Lann, J.M.; Joulia, X.; Sere-Peyrigain, P.

    1994-01-01

    Dynamic simulation of hydrogen isotope distillation unit involved in the complex environment of a fusion power plant can be a powerful technique in view to analyze the tritium hazard potential. Issues related to the development of such a dynamic simulator with model formulation and the numerical treatment of the resulting Differential-Algebraic equation (DAE) system are properly addressed. The typical dynamic characteristics of such columns are quantitatively and qualitatively enlightened on case study with very large disturbances. The developed system has proven to be beneficial for understanding the dynamic behaviour and further for developing control schemes. (author) 12 refs.; 4 figs

  10. Adsorption methods for hydrogen isotope storage on zeolite sieves

    International Nuclear Information System (INIS)

    Cristescu, Ioana; Cristescu, Ion; Vasut, Felicia; Brad, Sebastian; Lazar, Alin

    2001-01-01

    Adsorption molecular sieves and activated carbon were used for hydrogen isotopes. The adsorption process proceeds at liquid nitrogen and liquid hydrogen temperatures. The synthetic zeolites have similar properties as natural zeolites, but they have a regular pore structure and affinity for molecules of different size with defined shapes. Experimental results obtained at liquid nitrogen and liquid hydrogen temperatures evidenced the efficient behavior of the activated carbon and zeolite sieves for hydrogen isotope temporary storage. (authors)

  11. Hydrogen-water isotopic exchange process

    International Nuclear Information System (INIS)

    Cheung, H.

    1983-01-01

    Deuterium is concentrated in a hydrogen-water isotopic exchange process enhanced by the use of catalyst materials in cold and hot tower contacting zones. Water is employed in a closed liquid recirculation loop that includes the cold tower, in which deuterium is concentrated in the water, and the upper portion of the hot tower in which said deuterium is concentrated in the hydrogen stream. Feed water is fed to the lower portion of said hot tower for contact with the circulating hydrogen stream. The feed water does not contact the water in the closed loop. Catalyst employed in the cold tower and the upper portion of the hot tower, preferably higher quality material, is isolated from impurities in the feed water that contacts only the catalyst, preferably of lower quality, in the lower portion of the hot zone. The closed loop water passes from the cold zone to the dehumidification zone, and a portion of said water leaving the upper portion of the hot tower can be passed to the humidification zone and thereafter recycled to said closed loop. Deuterium concentration is enhanced in said catalytic hydrogen-water system while undue retarding of catalyst activity is avoided

  12. Evidence From Hydrogen Isotopes in Meteorites for a Martian Permafrost

    Science.gov (United States)

    Usui, T.; Alexander, C. M. O'D.; Wang, J.; Simon, J. I.; Jones, J. H.

    2014-01-01

    Fluvial landforms on Mars suggest that it was once warm enough to maintain persistent liquid water on its surface. The transition to the present cold and dry Mars is closely linked to the history of surface water, yet the evolution of surficial water is poorly constrained. We have investigated the evolution of surface water/ ice and its interaction with the atmosphere by measurements of hydrogen isotope ratios (D/H: deuterium/ hydrogen) of martian meteorites. Hydrogen is a major component of water (H2O) and its isotopes fractionate significantly during hydrological cycling between the atmosphere, surface waters, ground ice, and polar cap ice. Based on in situ ion microprobe analyses of three geochemically different shergottites, we reported that there is a water/ice reservoir with an intermediate D/H ratio (delta D = 1,000?2500 %) on Mars. Here we present the possibility that this water/ice reservoir represents a ground-ice/permafrost that has existed relatively intact over geologic time.

  13. Determination of fission gas yields from isotope ratios

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg

    1983-01-01

    This paper describes a method of calculating the actual fission yield of Kr and Xe in nuclear fuel including the effect of neutron capture reactions and decay. The bases for this calculation are the cumulative yields (ref. 1) of Kr and Xe isotopes (or pairs of isotopes) which are unaffected...... by neutron capture reactions, and measured Kr and Xe isotope ratios. Also the burnup contribution from the different fissile heavy isotopes must be known in order to get accurate fission gas yields....

  14. Combined electrolysis catalytic exchange (CECE) process for hydrogen isotope separation

    International Nuclear Information System (INIS)

    Hammerli, M.; Stevens, W.H.; Butler, J.P.

    1978-01-01

    Hydrogen isotopes can be separated efficiently by a process which combines an electrolysis cell with a trickle bed column packed with a hydrophobic platinum catalyst. The column effects isotopic exchange between countercurrent streams of electrolytic hydrogen and liquid water while the electrolysis cell contributes to isotope separation by virtue of the kinetic isotope effect inherent in the hydrogen evolution reaction. The main features of the CECE process for heavy water production are presented as well as a discussion of the inherent positive synergistic effects, and other advantages and disadvantages of the process. Several potential applications of the process in the nuclear power industry are discussed. 3 figures, 2 tables

  15. Continuous flow isotope ratio mass spectrometer (CF-IRMS) and its applications in hydrocarbon research and exploration

    International Nuclear Information System (INIS)

    Kalpana, G.; Patil, D.J.; Kumar, B.

    2004-01-01

    Stable isotope ratio mass spectrometers have been widely used to determine the isotopic ratios of light elements such as hydrogen, carbon, nitrogen, oxygen and sulphur. Continuous Flow Isotope Ratio Mass Spectrometry (CFIRMS) provides reliable data on nanomole amount of sample gas without the need for cryogenic trapping using cold fingers as in dual inlet isotope ratio mass spectrometer. High sample throughput is achieved as the system is configured with automated sample preparation devices and auto samplers. This paper presents a brief description of CFIRMS exploration

  16. System and method for high precision isotope ratio destructive analysis

    Science.gov (United States)

    Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

    2013-07-02

    A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

  17. Stable carbon and nitrogen isotope ratios of sodium and potassium cyanide as a forensic signature.

    Science.gov (United States)

    Kreuzer, Helen W; Horita, Juske; Moran, James J; Tomkins, Bruce A; Janszen, Derek B; Carman, April

    2012-01-01

    Sodium and potassium cyanide are highly toxic, produced in large amounts by the chemical industry, and linked to numerous high-profile crimes. The U.S. Centers for Disease Control and Prevention has identified cyanide as one of the most probable agents to be used in a chemical terrorism event. We investigated whether stable C and N isotopic content of sodium and potassium cyanide could serve as a forensic signature for sample matching, using a collection of 65 cyanide samples. Upon analysis, a few of the cyanide samples displayed nonhomogeneous isotopic content associated with degradation to a carbonate salt and loss of hydrogen cyanide. Most samples had highly reproducible isotope content. Of the 65 cyanide samples, >95% could be properly matched based on C and N isotope ratios, with a false match rate <3%. These results suggest that stable C and N isotope ratios are a useful forensic signature for matching cyanide samples. © 2011 American Academy of Forensic Sciences.

  18. Intracrystalline site preference of hydrogen isotopes in the water of crystallization of copper sulfate pentahydrate

    International Nuclear Information System (INIS)

    Kita, I.; Matsuo, S.

    1981-01-01

    Difference in the isotopic partition at different sites of the water of crystallization of CuSO 4 .5H 2 O (the site preference) was estimated for the hydrogen isotopes. Fractional dehydration of CuSO 4 .5H 2 O under vacuum at 0 and 25 0 C was used to determine the isotopic ratio, the amount of dehydrated water, and the rate process of dehydration. The following results were obtained. (1) Two maxima occur in the isotopic ratio in the dehydration range, F < 0.8. (2) The dehydration occurs by the three sequential zeroth-order rate processes which have different rate constants for dehydration. The three different rate constants may be explained by the combination of the rate constants of dehydration of the water molecules dehydrated. The estimation of the difference in hydrogen isotope distribution for different sites, i.e., four of the five water molecules in the coordination sphere of copper ion (site A) and one bonded to the sulfate ion through hydrogen bonding (site B) was made. The site preference of hydrogen isotopes (delta D,%) was concluded to be -3.20 +- 0.52 for site A and +2.26 +- 2.09 for site B, where the delta D value was referred to the isotopic ratio of the mother liquor from which the crystal was formed

  19. Intracrystalline site preference of hydrogen isotopes in the water of crystallization of copper sulfate pentahydrate

    Energy Technology Data Exchange (ETDEWEB)

    Kita, I.; Matsuo, S.

    1981-04-02

    Difference in the isotopic partition at different sites of the water of crystallization of CuSO/sub 4/.5H/sub 2/O (the site preference) was estimated for the hydrogen isotopes. Fractional dehydration of CuSO/sub 4/.5H/sub 2/O under vacuum at 0 and 25/sup 0/C was used to determine the isotopic ratio, the amount of dehydrated water, and the rate process of dehydration. The following results were obtained. (1) Two maxima occur in the isotopic ratio in the dehydration range, F < 0.8. (2) The dehydration occurs by the three sequential zeroth-order rate processes which have different rate constants for dehydration. The three different rate constants may be explained by the combination of the rate constants of dehydration of the water molecules dehydrated. The estimation of the difference in hydrogen isotope distribution for different sites, i.e., four of the five water molecules in the coordination sphere of copper ion (site A) and one bonded to the sulfate ion through hydrogen bonding (site B) was made. The site preference of hydrogen isotopes (delta D,%) was concluded to be -3.20 +- 0.52 for site A and +2.26 +- 2.09 for site B, where the delta D value was referred to the isotopic ratio of the mother liquor from which the crystal was formed.

  20. [Fractionation of hydrogen stable isotopes in the human body].

    Science.gov (United States)

    Siniak, Iu E; Grigor'ev, A I; Skuratov, V M; Ivanova, S M; Pokrovskiĭ, B G

    2006-01-01

    Fractionation of hydrogen stable isotopes was studied in 9 human subjects in a chamber with normal air pressure imitating a space cabin. Mass-spectrometry of isotopes in blood, urine, saliva, and potable water evidenced increases in the contents of heavy H isotope (deuterium) in the body liquids as compared with water. These results support one of the theories according to which the human organism eliminates heavy stable isotopes of biogenous chemical elements.

  1. Determination of the hydrogen isotopic compositions of organic materials and hydrous minerals using thermal combustion laser spectroscopy.

    Science.gov (United States)

    Koehler, Geoff; Wassenaar, Leonard I

    2012-04-17

    Hydrogen isotopic compositions of hydrous minerals and organic materials were measured by combustion to water, followed by optical isotopic analysis of the water vapor by off-axis integrated cavity output spectroscopy. Hydrogen and oxygen isotopic compositions were calculated by numerical integration of the individual isotopologue concentrations measured by the optical spectrometer. Rapid oxygen isotope exchange occurs within the combustion reactor between water vapor and molecular oxygen so that only hydrogen isotope compositions may be determined. Over a wide range in sample sizes, precisions were ±3-4 per mil. This is comparable but worse than continuous flow-isotope ratio mass spectroscopy (CF-IRMS) methods owing to memory effects inherent in water vapor transfer. Nevertheless, the simplicity and reduced cost of this analysis compared to classical IRMS or CF-IRMS methods make this an attractive option to determine the hydrogen isotopic composition of organic materials where the utmost precision or small sample sizes are not needed.

  2. Isotopic exchange of carbon-bound hydrogen over geologic timescales

    Science.gov (United States)

    Sessions, Alex L.; Sylva, Sean P.; Summons, Roger E.; Hayes, John M.

    2004-04-01

    The increasing popularity of compound-specific hydrogen isotope (D/H) analyses for investigating sedimentary organic matter raises numerous questions about the exchange of carbon-bound hydrogen over geologic timescales. Important questions include the rates of isotopic exchange, methods for diagnosing exchange in ancient samples, and the isotopic consequences of that exchange. This article provides a review of relevant literature data along with new data from several pilot studies to investigate such issues. Published experimental estimates of exchange rates between organic hydrogen and water indicate that at warm temperatures (50-100°C) exchange likely occurs on timescales of 104 to 108 yr. Incubation experiments using organic compounds and D-enriched water, combined with compound-specific D/H analyses, provide a new and highly sensitive method for measuring exchange at low temperatures. Comparison of δD values for isoprenoid and n-alkyl carbon skeletons in sedimentary organic matter provides no evidence for exchange in young (exchange in ancient (>350 Ma) rocks. Specific rates of exchange are probably influenced by the nature and abundance of organic matter, pore-water chemistry, the presence of catalytic mineral surfaces, and perhaps even enzymatic activity. Estimates of equilibrium fractionation factors between organic H and water indicate that typical lipids will be depleted in D relative to water by ∼75 to 140‰ at equilibrium (30°C). Thus large differences in δD between organic molecules and water cannot be unambiguously interpreted as evidence against hydrogen exchange. A better approach may be to use changes in stereochemistry as a proxy for hydrogen exchange. For example, estimated rates of H exchange in pristane are similar to predicted rates for stereochemical inversion in steranes and hopanes. The isotopic consequences of this exchange remain in question. Incubations of cholestene with D2O indicate that the number of D atoms incorporated during

  3. Precise and accurate isotope ratio measurements by ICP-MS.

    Science.gov (United States)

    Becker, J S; Dietze, H J

    2000-09-01

    The precise and accurate determination of isotope ratios by inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) is important for quite different application fields (e.g. for isotope ratio measurements of stable isotopes in nature, especially for the investigation of isotope variation in nature or age dating, for determining isotope ratios of radiogenic elements in the nuclear industry, quality assurance of fuel material, for reprocessing plants, nuclear material accounting and radioactive waste control, for tracer experiments using stable isotopes or long-lived radionuclides in biological or medical studies). Thermal ionization mass spectrometry (TIMS), which used to be the dominant analytical technique for precise isotope ratio measurements, is being increasingly replaced for isotope ratio measurements by ICP-MS due to its excellent sensitivity, precision and good accuracy. Instrumental progress in ICP-MS was achieved by the introduction of the collision cell interface in order to dissociate many disturbing argon-based molecular ions, thermalize the ions and neutralize the disturbing argon ions of plasma gas (Ar+). The application of the collision cell in ICP-QMS results in a higher ion transmission, improved sensitivity and better precision of isotope ratio measurements compared to quadrupole ICP-MS without the collision cell [e.g., for 235U/238U approximately 1 (10 microg x L(-1) uranium) 0.07% relative standard deviation (RSD) vs. 0.2% RSD in short-term measurements (n = 5)]. A significant instrumental improvement for ICP-MS is the multicollector device (MC-ICP-MS) in order to obtain a better precision of isotope ratio measurements (with a precision of up to 0.002%, RSD). CE- and HPLC-ICP-MS are used for the separation of isobaric interferences of long-lived radionuclides and stable isotopes by determination of spallation nuclide abundances in an irradiated tantalum target.

  4. Stable isotope ratio mass spectrometry in forensic science and food adulteration research

    International Nuclear Information System (INIS)

    Kumar, B.

    2009-01-01

    Stable Isotope Ratio Mass Spectrometry (SIRMS) is an established technique for the determination of origin of geological, biological, chemical and physio-chemical samples/materials. With the development of highly precise mass spectrometers, the stable isotope ratio determination of hydrogen, carbon, nitrogen and oxygen have gained considerable interest in the fields of forensic science and food authentication. Natural variations in the isotopic composition of lighter elements occur due to fractionation effects, resulting in the finger printing of specific isotope ratio values that are characteristic of the origin, purity, and manufacturing processes of the products and their constituents. Forensic science uses scientific and technical methods to investigate traceable evidence of criminal acts. Stable isotope ratio mass spectrometry has been applied to numerous aspects of the forensic science. The analysis of explosives such as ammonium nitrate, gun powder and tri-nitro-toluene (TNT), cases of murder, armed robbery, drug smuggling, terrorism, arson and hit and run traffic accidents are a few of them. The main types of geological evidences in such cases are mud, soil, rocks, sand, gravel, dust particles, biological materials, organic particles and anthropogenic components. Stable isotopes are used as tools to corroborate and confirm the evidential leads in the investigation of such crimes. The variation in natural abundances of carbon and nitrogen and their isotopic ratios δ 13 C and δ 15 N can identify links between items found at crime scene with those of suspect. The paper discusses the applications of SIRMS in the field of forensic science and food adulteration research

  5. Determination of uranium, thorium and radium isotope ratio

    International Nuclear Information System (INIS)

    Sokolova, Z.A.

    1983-01-01

    The problems connected with the study of isotope composition of natural radioactive elements in natural objects are considered. It is pointed out that for minerals, ores and rocks the following ratios are usually determined: 234 U/ 238 U, 230 Th/ 238 U, 226 Ra/ 238 U, 228 Th/ 230 Th, 228 Th/ 232 Th and lead isotopes; for natural waters, besides the enumerated - 226 Ra/ 228 Ra. General content of uranium and thorium in the course of isotope investigations is determined from separate samples, most frequently by the X-ray spectral method, radium content - by usual radiochemical method, uranium and radium content in waters -respectively by calorimetric and emanation methods. Radiochemical preparation of geologic powder and aqueous samples for isotope analysis is described in detail. The technique of measuring and calculating isotope ratios (α-spectrometry for determining isotope composition of uranium and thorium and emanation method for determining 226 Ra/ 228 Ra) is presented

  6. Device to remove hydrogen isotopes from a gas phase

    International Nuclear Information System (INIS)

    Morlock, G.; Wiesemes, J.; Bachner, D.

    1977-01-01

    The device described here guarantees the selective removal of hydrogen isotopes from gas phases in order to prevent the occurence of explosive H 2 gas mixtures, or to separate off radioactive tritium in nuclear plants from the gas phase. It consists of a closed container whose walls are selectively penetrable by hydrogen isotopes. It is simultaneously filled compactly and presssure-resistant with a metal bulk (e.g. powder, sponges or the like of titanium or other hydrogen isotope binding metal). Walling and bulk are maintained at suitable working temperatures by means of a system according to the Peltier effect. The whole thing is safeguarded by protective walling. (RB) [de

  7. Hydrogen Isotope Measurements of Organic Acids and Alcohols by Pyrolysis-GC-MS-TC-IRMS

    Science.gov (United States)

    Socki, Richard A.; Fu, Qi; Niles, Paul B.

    2011-01-01

    One possible process responsible for methane generation on Mars is abiotic formation by Fischer-Tropsch-type (FTT) synthesis during serpentinization reactions. Measurement of carbon and hydrogen isotopes of intermediary organic compounds can help constrain the origin of this methane by tracing the geochemical pathway during formation. Of particular interest within the context of this work is the isotopic composition of organic intermediaries produced on the surfaces of mineral catalysts (i.e. magnetite) during hydrothermal experiments, and the ability to make meaningful and reproducible hydrogen isotope measurements. Reported here are results of experiments to characterize the hydrogen isotope composition of low molecular weight organic acids and alcohols. The presence of these organic compounds has been suggested by others as intermeadiary products made during mineral surface catalyzed reactions. This work compliments our previous study characterizing the carbon isotope composition of similar low molecular weight intermediary organic compounds (Socki, et al, American Geophysical Union Fall meeting, Abstr. #V51B-2189, Dec., 2010). Our hydrogen isotope measurements utilize a unique analytical technique combining Pyrolysis-Gas Chromatograph-Mass Spectrometry-High Temperature Conversion-Isotope Ratio Mass Spectrometry (Py-GC-MS-TC-IRMS). Our technique is unique in that it carries a split of the pyrolyzed GC-separated product to a Thermo DSQ-II? quadrupole mass spectrometer as a means of making qualitative and semi-quantitative compositional measurements of separated organic compounds, therefore both chemical and isotopic measurements can be carried out simultaneously on the same sample.

  8. An improved data acquisition system for isotopic ratio mass spectrometers

    International Nuclear Information System (INIS)

    Saha, T.K.; Reddy, B.; Nazare, C.K.; Handu, V.K.

    1999-01-01

    Isotopic ratio mass spectrometers designed and fabricated to measure the isotopic ratios with a precision of better than 0.05%. In order to achieve this precision, the measurement system consisting of ion signal to voltage converters, analog to digital converters, and data acquisition electronics should be at least one order better than the overall precision of measurement. Using state of the art components and techniques, a data acquisition system, which is an improved version of the earlier system, has been designed and developed for use with multi-collector isotopic ratio mass spectrometers

  9. Simultaneous determination of stable carbon, oxygen, and hydrogen isotopes in cellulose.

    Science.gov (United States)

    Loader, N J; Street-Perrott, F A; Daley, T J; Hughes, P D M; Kimak, A; Levanič, T; Mallon, G; Mauquoy, D; Robertson, I; Roland, T P; van Bellen, S; Ziehmer, M M; Leuenberger, M

    2015-01-06

    A technological development is described through which the stable carbon-, oxygen-, and nonexchangeable hydrogen-isotopic ratios (δ(13)C, δ(18)O, δ(2)H) are determined on a single carbohydrate (cellulose) sample with precision equivalent to conventional techniques (δ(13)C 0.15‰, δ(18)O 0.30‰, δ(2)H 3.0‰). This triple-isotope approach offers significant new research opportunities, most notably in physiology and medicine, isotope biogeochemistry, forensic science, and palaeoclimatology, when isotopic analysis of a common sample is desirable or when sample material is limited.

  10. Mass spectrometric measurement of hydrogen isotope fractionation for the reactions of chloromethane with OH and Cl

    Directory of Open Access Journals (Sweden)

    F. Keppler

    2018-05-01

    Full Text Available Chloromethane (CH3Cl is an important provider of chlorine to the stratosphere but detailed knowledge of its budget is missing. Stable isotope analysis is a potentially powerful tool to constrain CH3Cl flux estimates. The largest degree of isotope fractionation is expected to occur for deuterium in CH3Cl in the hydrogen abstraction reactions with its main sink reactant tropospheric OH and its minor sink reactant Cl atoms. We determined the isotope fractionation by stable hydrogen isotope analysis of the fraction of CH3Cl remaining after reaction with hydroxyl and chlorine radicals in a 3.5 m3 Teflon smog chamber at 293 ± 1 K. We measured the stable hydrogen isotope values of the unreacted CH3Cl using compound-specific thermal conversion isotope ratio mass spectrometry. The isotope fractionations of CH3Cl for the reactions with hydroxyl and chlorine radicals were found to be −264±45 and −280±11 ‰, respectively. For comparison, we performed similar experiments using methane (CH4 as the target compound with OH and obtained a fractionation constant of −205±6 ‰ which is in good agreement with values previously reported. The observed large kinetic isotope effects are helpful when employing isotopic analyses of CH3Cl in the atmosphere to improve our knowledge of its atmospheric budget.

  11. MIR hollow waveguide (HWG) isotope ratio analyzer for environmental applications

    Science.gov (United States)

    Wang, Zhenyou; Zhuang, Yan; Deev, Andrei; Wu, Sheng

    2017-05-01

    An advanced commercial Mid-InfraRed Isotope Ratio (IR2) analyzer was developed in Arrow Grand Technologies based on hollow waveguide (HWG) as the sample tube. The stable carbon isotope ratio, i.e. δ13C, was obtained by measuring the selected CO2 absorption peaks in the MIR. Combined with a GC and a combustor, it has been successfully employed to measure compound specific δ13C isotope ratios in the field. By using both the 1- pass HWG and 5-path HWG, we are able to measure δ13C isotope ratio at a broad CO2 concentration of 300 ppm-37,500 ppm. Here, we demonstrate its applications in environmental studies. The δ13C isotope ratio and concentration of CO2 exhaled by soil samples was measured in real time with the isotope analyzer. The concentration was found to change with the time. We also convert the Dissolved Inorganic Carbon (DIC) into CO2, and then measure the δ13C isotope ratio with an accuracy of better than 0.3 ‰ (1 σ) with a 6 min test time and 1 ml sample usage. Tap water, NaHCO3 solvent, coca, and even beer were tested. Lastly, the 13C isotope ratio of CO2 exhaled by human beings was obtained <10 seconds after simply blowing the exhaled CO2 into a tube with an accuracy of 0.5‰ (1 σ) without sample preconditioning. In summary, a commercial HWG isotope analyzer was demonstrated to be able to perform environmental and health studies with a high accuracy ( 0.3 ‰/Hz1/2 1 σ), fast sampling rate (up to 10 Hz), low sample consumption ( 1 ml), and broad CO2 concentration range (300 ppm-37,500 ppm).

  12. Gas-chromatographic separation of hydrogen isotopic mixtures

    International Nuclear Information System (INIS)

    Preda, Anisoara; Bidica, Nicolae

    2005-01-01

    Full text: Gas chromatographic separation of hydrogen isotopes have been reported in the literature since late of 1950's. Gas chromatography is primarily an analytical method, but because of its properties it may be used in many other fields with excellent results. A simple method is proposed for the gas-chromatographic analysis of complex gas mixtures containing hydrogen isotopes; the method is based on the substantial difference in the thermal conductivity of these isotopes. One of the main disadvantages of the conventional gas chromatography is the long retention times required for the analysis of hydrogen gas mixtures while the column is operated at very low temperature. The method described in this paper was based on using a capillary molecular sieve 5A column operated for this kind of separation at 173 K. The carrier gas was Ne and the detector was TCD. In the paper chromatograms for various carrier flow rates and various hydrogen isotope mixtures are presented. (authors)

  13. Novel catalysts for isotopic exchange between hydrogen and liquid water

    International Nuclear Information System (INIS)

    Butler, J.P.; Rolston, J.H.; Stevens, W.H.

    1978-01-01

    Catalytic isotopic exchange between hydrogen and liquid water offers many inherent potential advantages for the separation of hydrogen isotopes which is of great importance in the Canadian nuclear program. Active catalysts for isotopic exchange between hydrogen and water vapor have long been available, but these catalysts are essentially inactive in the presence of liquid water. New, water-repellent platinum catalysts have been prepared by: (1) treating supported catalysts with silicone, (2) depositing platinum on inherently hydrophobic polymeric supports, and (3) treating platinized carbon with Teflon and bonding to a carrier. The activity of these catalysts for isotopic exchange between countercurrent streams of liquid water and hydrogen saturated with water vapor has been measured in a packed trickle bed integral reactor. The performance of these hydrophobic catalysts is compared with nonwetproofed catalysts. The mechanism of the overall exchange reaction is briefly discussed. 6 figures

  14. Isotope analytics for the evaluation of the feeding influence on the isotope ratio in beef samples

    International Nuclear Information System (INIS)

    Herwig, Nadine

    2010-01-01

    Information about the origin of food and associated production systems has a high significance for food control. An extremely promising approach to obtain such information is the determination of isotope ratios of different elements. In this study the correlation of the isotope ratios C-13/C-12, N-15/N-14, Mg-25/Mg-24, and Sr-87/Sr-86 in bovine samples (milk and urine) and the corresponding isotope ratios in feed was investigated. It was shown that in the bovine samples all four isotope ratios correlate with the isotope composition of the feed. The isotope ratios of strontium and magnesium have the advantage that they directly reflect the isotope ratios of the ingested feed since there is no isotope fractionation in the bovine organism which is in contrast to the case of carbon and nitrogen isotope ratios. From the present feeding study it is evident, that a feed change leads to a significant change in the delta C-13 values in milk and urine within 10 days already. For the deltaN-15 values the feed change was only visible in the bovine urine after 49 days. Investigations of cows from two different regions (Berlin/Germany and Goestling/Austria) kept at different feeding regimes revealed no differences in the N-15/N-14 and Mg-26/Mg-24 isotope ratios. The strongest correlation between the isotope ratio of the bovine samples and the kind of ingested feed was observed for the carbon isotope ratio. With this ratio even smallest differences in the feed composition were traceable in the bovine samples. Since different regions usually coincide with different feeding regimes, carbon isotope ratios can be used to distinguish bovine samples from different regions if the delta C-13 values of the ingested feed are different. Furthermore, the determination of strontium isotope ratios revealed significant differences between bovine and feed samples of Berlin and Goestling due to the different geologic realities. Hence the carbon and strontium isotope ratios allow the best

  15. Vapour pressure isotope effects in liquid hydrogen chloride

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, J.N.C.; Calado, J.C.G. (Instituto Superior Tecnico, Lisbon (Portugal)); Jancso, Gabor (Hungarian Academy of Sciences, Budapest (Hungary). Central Research Inst. for Physics)

    1992-08-10

    The difference between the vapour pressures of HCl and DCl has been measured over the temperature range 170-203 K by a differential manometric technique in a precision cryostat. In this range the vapour pressure of HCl is higher than that of DCl by 3.2% at 170 K, decreasing to 0.9% at 200 K. The reduced partition function ratios f[sub l]/f[sub g] derived from the vapour pressure data can be described by the equation ln(f[sub l]/f[sub g]) = (3914.57[+-]10)/T[sup 2] - (17.730[+-]0.055)/T. The experimentally observed H-D vapour pressure isotope effect, together with the values on the [sup 35]Cl-[sup 37]Cl isotope effect available in the literature, is interpreted in the light of the statistical theory of isotope effects in condensed systems by using spectroscopic data of the vapour and liquid phases. The results indicate that the rotation in liquid hydrogen chloride is hindered. Temperature-dependent force constants for the hindered translational and rotational motions were invoked in order to obtain better agreement between the model calculation and experiment. (author).

  16. Isotope ratios of lead as pollutant source indicators

    International Nuclear Information System (INIS)

    Chow, T.J.; Snyder, C.B.; Earal, J.L.

    1975-01-01

    Each lead ore deposit has its characteristic isotope ratios which are fixed during mineral ore genesis, and this unique property can be used to indicate the source of lead pollutants in the environment. The wolld production of primary lead is tabulated, and the geochemical significances of lead isotope ratios are discussed. The manufacture of lead alkyl additives for gasoline, which is the major source of lead pollutants, utilizes about 10% of the world annual consumption of lead. The isotope ratios of lead in gasoline, aerosols, soils and plants are correlated. Lead additives in various brands of gasoline sold in one region do not have the same isotope ratios. Regional variations in isotope ratios of lead additives were observed. This reflects the fact that petroleum refineries obtained the additives from various lead alkyl manufacturers which utilized lead from different mining districts. A definite changing trend of isotope ratios of lead pollutants in the San Diego, California (USA), area was detected. The lead shows a gradual increase in its radiogenic components during the past decade. This trend can be explained by the change of lead sources used by the additive manufacturers: Lead isotope ratios of the mid-1960's gasoline additives in the United States of America reflected those of less radiogenic leads imported from Canada, Australia, Peru and Mexico. Since then, the U.S. lead production has doubled-mainly from the Missouri district of highly radiogenic lead. Meanwhile, there has been a decrease in total lead imports. These combined effects result in changes in isotope ratios, from the less to more radiogenic, of the pooled lead. (aothor)

  17. Lead isotope ratios in artists' lead white: a progress report

    Energy Technology Data Exchange (ETDEWEB)

    Keisch, B; Callahan, R C [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA)

    1976-07-01

    The lead isotope ratios in over four hundred samples of lead white have been determined. The samples represent various geographical sources and dates from the thirteenth century to the present. A new method for organizing this large volume of data is described which helps with the visualization of temporal and geographic patterns. A number of interesting relationships between lead isotope ratio and date or source are shown to exist. Some examples of successful applications of this methodology are described.

  18. Isotopic Ratios of Samarium by TIMS for Nuclear Forensic Application

    Energy Technology Data Exchange (ETDEWEB)

    Louis Jean, James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Inglis, Jeremy David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-08

    The isotopic ratio of Nd, Sm, and Gd can provide important information regarding fissile material (nuclear devices, reactors), neutron environment, and device yield. These studies require precise measurement of Sm isotope ratios, by either TIMS or MC-ICP-MS. There has been an increasing trend to measure smaller and smaller quantities of Sm bearing samples. In nuclear forensics 10-100 ng of Sm are needed for precise measurement. To measure sub-ng Sm samples using TIMS for nuclear forensic analysis.

  19. Lead isotope ratios in artists' lead white: a progress report

    International Nuclear Information System (INIS)

    Keisch, B.; Callahan, R.C.

    1976-01-01

    The lead isotope ratios in over four hundred samples of lead white have been determined. The samples represent various geographical sources and dates from the thirteenth century to the present. A new method for organizing this large volume of data is described which helps with the visualization of temporal and geographic patterns. A number of interesting relationships between lead isotope ratio and date or source are shown to exist. Some examples of successful applications of this methodology are described. (author)

  20. Variations in the stable isotope ratios of specific aromatic and aliphatic hydrocarbons from coal conversion processes

    Energy Technology Data Exchange (ETDEWEB)

    McRae, C.; Snape, C.E.; Fallick, A.E. [University of Strathclyde, Glasgow (United Kingdom). Dept. of Pure and Applied Chemistry

    1998-07-01

    To establish the scope for applying gas chromatography-isotope ratio mass spectrometry ({sup {delta}-13}C GC-IRMS) to molecular recognition problems in coal utilisation, {sup 13}C/{sup 12}C isotope ratios were determined for n-alkanes and polycyclic aromatic hydrocarbons (PAHs) as a function of coal rank and process conditions. Six coals ranging from a lignite to a low volatile bituminous coal were subjected to chloroform extraction, fixed-bed pyrolysis under hydrogen pressure (hydropyrolysis) and fluidised-bed (flash) pyrolysis. No significant variations in the stable isotope ratios of n-alkanes were evident as a function of either rank or conversion regime. In contrast, the isotope ratios of PAHs show large variations with those for hydropyrolysis (-23 to -25 parts per thousand) being similar to the bulk values of the initial coals and being isotopically heavier (less negative) than their fluidised-bed pyrolysis counterparts by 2-3 parts per thousand. However, the PAHs from fluidised-bed pyrolysis, which resemble closely those obtained from high temperature coal carbonization, are still heavier (by 2-3 parts per thousand) than those from diesel particulates and coal gasification and combustion residues. This provides a firm basis for the source apportionment of airborne PAHs in the proximity of coking plants, particularly with no major variations in the PAH isotope ratios being found as a function of rank.

  1. Separation of hydrogen isotopes via single column pressure swing adsorption

    International Nuclear Information System (INIS)

    Wong, Y.W.; Hill, F.B.

    1981-01-01

    Separation of hydrogen isotopes based on kinetic isotope effects was studied. The mixture separated was hydrogen containing a trace of tritium as HT and the hydride was vanadium monohydride. The separation was achieved using the single-column pressure swing process. Stage separation factors are larger and product cuts smaller than for a two-column pressure swing process operated in the same monohydride phase

  2. Hydrogen isotope separation in hydrophobic catalysts between hydrogen and liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Linsen, E-mail: yls2005@mail.ustc.edu.cn [China Academy of Engineering Physics, Mianyang 621900 (China); Luo, Deli [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621907 (China); Tang, Tao; Yang, Wan; Yang, Yong [China Academy of Engineering Physics, Mianyang 621900 (China)

    2015-11-15

    Hydrogen isotope catalytic exchange between hydrogen and liquid water is a very effective process for deuterium-depleted potable water production and heavy water detritiation. To improve the characteristics of hydrophobic catalysts for this type of reaction, foamed and cellular structures of hydrophobic carbon-supported platinum catalysts were successfully prepared. Separation of deuterium or tritium from liquid water was carried out by liquid-phase catalytic exchange. At a gas–liquid ratio of 1.53 and exchange temperature of 70 °C, the theoretical plate height of the hydrophobic catalyst (HETP = 34.2 cm) was slightly lower than previously reported values. Changing the concentration of the exchange column outlet water yielded nonlinear changes in the height of the packing layer. Configurations of deuterium-depleted potable water and detritiation of heavy water provide references for practical applications.

  3. Isotope yield ratios as a probe of the reaction dynamics

    International Nuclear Information System (INIS)

    Trautmann, W.; Hildenbrand, K.D.; Lynen, U.; Mueller, W.F.J.; Rabe, H.J.; Sann, H.; Stelzer, H.; Trockel, R.; Wada, R.; Brummund, N.; Glasow, R.; Kampert, K.H.; Santo, R.; Eckert, E.M.; Pochodzalla, J.; Bock, I.; Pelte, D.

    1987-04-01

    Isotopically resolved yields of particles and complex fragments from 12 C and 18 O induced reactions on 53 Ni, 54 Ni, Ag, and 197 Au in the intermediate range of bombarding energies 30 MeV ≤ E/A ≤ 84 MeV were measured. The systematic variation of the deduced isotope yield ratios with projectile and target is used to determine the degree of N/Z equilibration achieved and to establish time scales for the reaction process. A quantum statistical model is employed in order to derive entropies of the emitting systems from the measured isotope yield ratios. (orig.)

  4. Hydrogen isotope recovering and reutilizing method and its device

    International Nuclear Information System (INIS)

    Ide, Takahiro.

    1988-01-01

    Purpose: To enable safety and convenient recovery and reutilization of gaseous tritium and other hydrogen isotopes. Constitution: Two kinds of metal hydrides different from each other in the dissociation pressure at an identical temperature are combined, in which a metal hydride of higher dissociation pressure is used for recovery and reutilization for most portion of gaseous hydrogen isotope gases, while the metal hydride of lower dissociation pressure is used for the recovery and reutilization of the remaining gaseous hydrogen isotopes. This enables to extremely lower the concentration of the remaining gaseous hydrogen isotopes, that is, the concentration of tritium in the recoverying system. In addition, since the heating temperature required for releasing the gaseous hydrogen isotopes absorbed in both of the metal hydrides is within such a range as causing no problem for the permeation of the gaseous hydrogen isotopes, there is no requirement for the countermeasure to tritium permeation or the facility for recovering permeated tritium and there is no problem for the material degradation due to the heating at high temperature. (Kawakami, Y.)

  5. Development of a new method for hydrogen isotope analysis of trace hydrocarbons in natural gas samples

    Directory of Open Access Journals (Sweden)

    Xibin Wang

    2016-12-01

    Full Text Available A new method had been developed for the analysis of hydrogen isotopic composition of trace hydrocarbons in natural gas samples by using solid phase microextraction (SPME combined with gas chromatography-isotope ratio mass spectrometry (GC/IRMS. In this study, the SPME technique had been initially introduced to achieve the enrichment of trace content of hydrocarbons with low abundance and coupled to GC/IRMS for hydrogen isotopic analysis. The main parameters, including the equilibration time, extraction temperature, and the fiber type, were systematically optimized. The results not only demonstrated that high extraction yield was true but also shows that the hydrogen isotopic fractionation was not observed during the extraction process, when the SPME device fitted with polydimethylsiloxane/divinylbenzene/carbon molecular sieve (PDMS/DVB/CAR fiber. The applications of SPME-GC/IRMS method were evaluated by using natural gas samples collected from different sedimentary basins; the standard deviation (SD was better than 4‰ for reproducible measurements; and also, the hydrogen isotope values from C1 to C9 can be obtained with satisfying repeatability. The SPME-GC/IRMS method fitted with PDMS/DVB/CAR fiber is well suited for the preconcentration of trace hydrocarbons, and provides a reliable hydrogen isotopic analysis for trace hydrocarbons in natural gas samples.

  6. Separation of Hydrogen Isotopes by Palladium Alloy Membranes Separator

    International Nuclear Information System (INIS)

    Jiangfeng, S.; Deli, L.; Yifu, X.; Congxian, L.; Zhiyong, H.

    2007-01-01

    Full text of publication follows: Separation of hydrogen isotope with palladium alloy membranes is one of the promising methods for hydrogen isotope separation. It has several advantages, such as high separation efficiency, smaller tritium inventory, simple separation device, ect. Limited by the manufacture of membrane and cost of gas transportation pump, this method is still at the stage of conceptual study. The relationship between separation factors and temperatures, feed gas components, split ratios have not been researched in detail, and the calculated results of cascade separation have not been validated with experimental data. In this thesis, a palladium alloy membrane separator was designed to further study its separation performance between H 2 and D 2 . The separation factor of the single stage was affected by the temperature, the feed gas component, the split ratio and the gas flow rate, etc. The experimental results showed that the H 2 -D 2 separation factor decreased with the increasing of temperature. On the temperature from 573 K to 773 K, when the feed rate was 5 L/min, the separation factor of 66.2%H 2 - 33.8%D 2 decreased from 2.09 to 1.85 when the split ratio was 0.1 and from 1.74 to 1.52 when the split ratio was 0.2.The separation factor also decreased with the increasing of split ratio. At 573 K and the feed rate of 5 L/min, the separation factor of 15.0%H 2 and 85.0%D 2 decreased from 2.43 to 1.35 with the increasing of split ratio from 0.050 to 0.534,and for 66.2%H 2 -33.8%D 2 , the separation factor decreased from 2.87 to 1.30 with the increasing of split ratio from 0.050 to 0.688. When the separation factor was the biggest, the flow rate of feed gas was in a perfect value. To gain a best separation performance, perfect flow rate, lower temperature and reflux ratio should be chosen. (authors)

  7. Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS)--discrimination of ammonium nitrate sources.

    Science.gov (United States)

    Benson, Sarah J; Lennard, Christopher J; Maynard, Philip; Hill, David M; Andrew, Anita S; Roux, Claude

    2009-06-01

    An evaluation was undertaken to determine if isotope ratio mass spectrometry (IRMS) could assist in the investigation of complex forensic cases by providing a level of discrimination not achievable utilising traditional forensic techniques. The focus of the research was on ammonium nitrate (AN), a common oxidiser used in improvised explosive mixtures. The potential value of IRMS to attribute Australian AN samples to the manufacturing source was demonstrated through the development of a preliminary AN classification scheme based on nitrogen isotopes. Although the discrimination utilising nitrogen isotopes alone was limited and only relevant to samples from the three Australian manufacturers during the evaluated time period, the classification scheme has potential as an investigative aid. Combining oxygen and hydrogen stable isotope values permitted the differentiation of AN prills from three different Australian manufacturers. Samples from five different overseas sources could be differentiated utilising a combination of the nitrogen, oxygen and hydrogen isotope values. Limited differentiation between Australian and overseas prills was achieved for the samples analysed. The comparison of nitrogen isotope values from intact AN prill samples with those from post-blast AN prill residues highlighted that the nitrogen isotopic composition of the prills was not maintained post-blast; hence, limiting the technique to analysis of un-reacted explosive material.

  8. Intracrystalline site preference of hydrogen isotopes in borax

    International Nuclear Information System (INIS)

    Pradhananga, T.M.; Matsuo, S.

    1985-01-01

    The total hydrogen involved in borax synthesized at 25 0 C in aqueous solution is enriched in deuterium by 5.3% compared with the mother liquor. There is no change in the value of the D/H fractionation factor between the hydrogen in borax and those in the mother liquor with changes in the degree of supersaturation. The fractionation factor changes slightly with a change in the crystallization temperature of borax in the range from 5 to 25 0 C. The D/H ratio in the different sites of borax was estimated by a fractional dehydration technique. The results show that hydrogen atoms of the polyanionic group [B 4 O 5 (OH) 4 ] are much more enriched in deuterium than those of the cationic group [Na 2 x 8H 2 O]. The delta D values, referred to the mother liquor from which the borax was crystallized, for the cationic group (site A) and the polyanionic group (site B) are -35 +/- 3 and 167 +/- 13%, respectively based on the fractional dehydration results obtained at -21 0 C. At -21 0 C, isotopic exchange between different sites during dehydration is assumed not to occur. The mechanism for dehydration of borax is discussed. 48 references, 8 figures, 3 tables

  9. Isotope mixtures of hydrogen in vanadium

    International Nuclear Information System (INIS)

    Mecking-Schloetensack, P.

    1982-03-01

    The properties of isotope-mixtures of Protium and Deuterium stored in Vanadium have been studied. Protium and Deuterium are existing as interstitial-atoms on tetrahedral sites as well as on octahedral sites in this system. This feature leads to large isotopic-effects between the two isotopes. The dependence of the thermodynamic functions like heat of solution, nonconfigurational entropy, specific heat and ordering temperatures from the composition of the isotope-mixture has been determined. (orig.)

  10. Determination of hydrogen isotope composition in organic compounds

    International Nuclear Information System (INIS)

    Ordzhonikidze, K.G.; Parulava, L.P.; Vakhaniya, G.V.; Tarielashvili, V.O.

    1989-01-01

    method for determination of hydrogen isotope composition just in organic compounds using mass-spectrometer of the second class is suggested. The method enables to determine atomic fraction of hydrogen without multiplet separation. The accuracy of determination of deuterium atomic fraction in acetone in 1-99% range was equal to 3-0.2% respectively

  11. Laser Spectroscopic Analysis of Liquid Water Samples for Stable Hydrogen and Oxygen Isotopes

    International Nuclear Information System (INIS)

    2009-01-01

    Stable isotope ratios of hydrogen and oxygen are tracers of choice for water cycle processes in hydrological, atmospheric and ecological studies. The use of isotopes has been limited to some extent because of the relatively high cost of isotope ratio mass spectrometers and the need for specialized operational skills. Here, the results of performance testing of a recently developed laser spectroscopic instrument for measuring stable hydrogen and oxygen isotope ratios of water samples are described, along with a procedure for instrument installation and operation. Over the last four years, the IAEA Water Resources Programme conducted prototype and production model testing of these instruments and this publication is the outcome of those efforts. One of the main missions of the IAEA is to promote the use of peaceful applications of isotope and nuclear methods in Member States and this publication is intended to facilitate the use of laser absorption based instruments for hydrogen and oxygen stable isotope analyses of liquid water samples for hydrological and other studies. The instrument uses off-axis integrated cavity output spectroscopy to measure absolute abundances of 2 HHO, HH 18 O, and HHO via laser absorption. Test results using a number of natural and synthetic water standards and samples with a large range of isotope values demonstrate adequate precision and accuracy (e.g. precisions of 1 per mille for δ 2 H and 0.2 per mille for δ 18 O). The laser instrument has much lower initial and maintenance costs than mass spectrometers and is substantially easier to operate. Thus, these instruments have the potential to bring about a paradigm shift in isotope applications by enabling researchers in all fields to measure isotope ratios by themselves. The appendix contains a detailed procedure for the installation and operation of the instrument. Using the procedure, new users should be able to install the instrument in less than two hours. It also provides step

  12. Interaction of hydrogen and its isotopes with irradiated beryllium

    International Nuclear Information System (INIS)

    Tazhibaeva, I.L.; Shestakov, V.P.; Klepikov, A.Kh.; Pomanenko, O.G.; Chikhraj, E.V.; Kenzhin, E.A.; Zverev, V.V.; Kolbanenkov, A.N.

    2000-01-01

    In the article the results of experiments on hydrogen and its isotopes accumulation and gas-release from irradiated beryllium are presented. The irradiation was conducted at different media and temperatures in the RA and IVG.1M reactors. The measurements were carried out by thermal desorption method. Hydrogen release from beryllium samples saturated at different conditions were calculated. Dependence of hydrogen confinement character in beryllium from grain orientation in the sample, temperature and irradiation rate was revealed

  13. Interactions of hydrogen isotopes and oxides with metal tubes

    International Nuclear Information System (INIS)

    Longhurst, G. R.; Cleaver, J.

    2008-01-01

    Understanding and accounting for interaction of hydrogen isotopes and their oxides with metal surfaces is important for persons working with tritium systems. Reported data from several investigators have shown that the processes of oxidation, adsorption, absorption, and permeation are all coupled and interactive. A computer model has been developed for predicting the interaction of hydrogen isotopes and their corresponding oxides in a flowing carrier gas stream with the walls of a metallic tube, particularly at low hydrogen concentrations. An experiment has been constructed to validate the predictive model. Predictions from modeling lead to unexpected experiment results. (authors)

  14. Interactions of hydrogen isotopes and oxides with metal tubes

    Energy Technology Data Exchange (ETDEWEB)

    Longhurst, G. R. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3860 (United States); Cleaver, J. [Idaho State Univ., 921 South 8th Avenue, Pocatello, ID 83201 (United States)

    2008-07-15

    Understanding and accounting for interaction of hydrogen isotopes and their oxides with metal surfaces is important for persons working with tritium systems. Reported data from several investigators have shown that the processes of oxidation, adsorption, absorption, and permeation are all coupled and interactive. A computer model has been developed for predicting the interaction of hydrogen isotopes and their corresponding oxides in a flowing carrier gas stream with the walls of a metallic tube, particularly at low hydrogen concentrations. An experiment has been constructed to validate the predictive model. Predictions from modeling lead to unexpected experiment results. (authors)

  15. Interactions of Hydrogen Isotopes and Oxides with Metal Tubes

    International Nuclear Information System (INIS)

    Longhurst, Glen R.

    2008-01-01

    Understanding and accounting for interaction of hydrogen isotopes and their oxides with metal surfaces is important for persons working with tritium systems. Reported data from several investigators have shown that the processes of oxidation, adsorption, absorption, and permeation are all coupled and interactive. A computer model has been developed for predicting the interaction of hydrogen isotopes and their corresponding oxides in a flowing carrier gas stream with the walls of a metallic tube, particularly at low hydrogen concentrations. An experiment has been constructed to validate the predictive model. Predictions from modeling lead to unexpected experiment results

  16. LITERATURE SURVEY ON ISOTOPIC ABUNDANCE RATIO MEASUREMENTS - 2001-2005

    International Nuclear Information System (INIS)

    HOLDEN, N.E.

    2005-01-01

    Along with my usual weekly review of the published literature for new nuclear data, I also search for new candidates for best measurements of isotopic abundances from a single source. Most of the published articles, that I previously had found in the Research Library at the Brookhaven Lab, have already been sent to the members of the Atomic Weights Commission, by either Michael Berglund or Thomas Walczyk. In the last few days, I checked the published literature for any other articles in the areas of natural variations in isotopic abundance ratios, measurements of isotopic abundance ratios on samples of extra-terrestrial material and isotopic abundance ratio measurements performed using ICPMS instruments. Hopefully this information will be of interest to members of the Commission, the sub-committee on isotopic abundance measurements (SIAM), members of the former sub-committee on natural isotopic fractionation (SNIF), the sub-committee on extra-terrestrial isotope ratios (SETIR), the RTCE Task Group and the Guidelines Task Group, who are dealing with ICPMS and TIMS comparisons. In the following report, I categorize the publications in one of four areas. Measurements performed using either positive or negative ions with Thermal Ionization Mass Spectrometer, TIMS, instruments; measurements performed on Inductively Coupled Plasma Mass Spectrometer, ICPMS, instruments; measurements of natural variations of the isotopic abundance ratios; and finally measurements on extra-terrestrial samples with instrumentation of either type. There is overlap in these areas. I selected out variations and ET results first and then categorized the rest of the papers by TIMS and ICPMS

  17. Multi-saline sample distillation apparatus for hydrogen isotope analyses : design and accuracy

    Science.gov (United States)

    Hassan, Afifa Afifi

    1981-01-01

    A distillation apparatus for saline water samples was designed and tested. Six samples may be distilled simultaneously. The temperature was maintained at 400 C to ensure complete dehydration of the precipitating salts. Consequently, the error in the measured ratio of stable hydrogen isotopes resulting from incomplete dehydration of hydrated salts during distillation was eliminated. (USGS)

  18. Transport hysteresis and hydrogen isotope effect on confinement

    Science.gov (United States)

    Itoh, S.-I.; Itoh, K.

    2018-03-01

    A Gedankenexperiment on hydrogen isotope effect is developed, using the transport model with transport hysteresis. The transport model with hysteresis is applied to case where the modulational electron cyclotron heating is imposed near the mid-radius of the toroidal plasmas. The perturbation propagates either outward or inward, being associated with the clockwise (CW) hysteresis or counter-clockwise (CCW) hysteresis, respectively. The hydrogen isotope effects on the CW and CCW hysteresis are investigated. The local component of turbulence-driven transport is assumed to be the gyro-Bohm diffusion. While the effect of hydrogen mass number is screened in the response of CW hysteresis, it is amplified in CCW hysteresis. This result motivates the experimental studies to compare CW and CCW cases in order to obtain further insight into the physics of hydrogen isotope effects.

  19. Coupled hydrogen moderator optimization with ortho/para hydrogen ratio

    International Nuclear Information System (INIS)

    Kai, Tetsuya; Harada, Masahide; Teshigawara, Makoto; Watanabe, Noboru; Ikeda, Yujiro

    2004-01-01

    Neutronic performance of a coupled hydrogen moderator was studied as a function of para hydrogen concentration, moderator thickness and height, premoderator thickness, etc. for the J-PARC spallation neutron source. It was found that a thick (140 mm) moderator with 100% para-hydrogen was optimal to provide a high time- and energy-integrated neutron intensity below 15 meV and high pulse-peak intensities at lower energies. Distribution of the cold neutrons on a moderator viewed surface was studied and found to exhibit an intensity-enhanced region at the fringe part near the premoderator. This rather peculiar distribution suggested that the moderator and the viewed surface must be designed so as to take the full advantage of the brighter region near the premoderator

  20. Applications of stable Isotope ratios determinations in fruit juice authentication

    International Nuclear Information System (INIS)

    Magdas, Dana Alina; Dehelean, Adriana; Voica, Cezara; Puscas, Romulus

    2010-01-01

    Full text: Adulteration of a product consists in making it impure by fraudulent addition of a foreign or inferior substance. The result is either an alteration of the product and of its quality or a falsification. The falsification is a voluntary act with the intention of abuse. The falsification may be more or less sophisticated and its sophistication as well as its costs increases with the improvement of analytical methods. Vacuum concentration with aroma does not affect the chemical composition of fruit juices and therefore the determination of deuterium (D) and oxygen-18 content in waters is the most confident procedure for differentiating between a natural single strength juice and a juice rediluted from a concentrate. This technique is based on the fact that when absorbed by a plant, the rainwater or the irrigation water is fractionated by evapotranspiration, and enriched in the heavy isotopes (deuterium and oxygen-18) with respect to the light isotope (hydrogen and oxygen-16, respectively). It is known that climatic conditions affect the isotope content of rain waters and therefore that of fruit juices waters: the warmer climate, the higher the deuterium and oxygen-18 contents in water. Rainwater and tap water have nearly the same isotopic content and the water of fruit juices derived from concentrate by dilution with tap water has an isotopic content close to that of tap water. This makes it easy to distinguish diluted concentrates from the isotopically more enriched water of authentic single strength juice. In this study, single strength juice, in Romanian fruits, were investigated by mean of stable isotope measurements (oxygen, hydrogen and carbon) in order to offer a discussion basis for the authenticity of some fruit juices currently available on Romanian market. (authors)

  1. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  2. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  3. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

  4. Isotope Ratio Monitoring Gas Chromatography Mass Spectrometry (IRM-GCMS)

    International Nuclear Information System (INIS)

    Freeman, K.H.; Ricci, S.A.; Studley, A.; Hayes, J.M.

    1989-01-01

    On Earth, the C-13 content of organic compounds is depleted by roughly 13 to 23 permil from atmospheric carbon dioxide. This difference is largely due to isotope effects associated with the fixation of inorganic carbon by photosynthetic organisms. If life once existed on Mars, then it is reasonable to expect to observe a similar fractionation. Although the strongly oxidizing conditions on the surface of Mars make preservation of ancient organic material unlikely, carbon-isotope evidence for the existence of life on Mars may still be preserved. Carbon depleted in C-13 could be preserved either in organic compounds within buried sediments, or in carbonate minerals produced by the oxidation of organic material. A technique is introduced for rapid and precise measurement of the C-13 contents of individual organic compounds. A gas chromatograph is coupled to an isotope-ratio mass spectrometer through a combustion interface, enabling on-line isotopic analysis of isolated compounds. The isotope ratios are determined by integration of ion currents over the course of each chromatographic peak. Software incorporates automatic peak determination, corrections for background, and deconvolution of overlapped peaks. Overall performance of the instrument was evaluated by the analysis of a mixture of high purity n-alkanes of know isotopic composition. Isotopic values measured via IRM-GCMS averaged withing 0.55 permil of their conventionally measured values

  5. Isotope ratios as pollutant source and behaviour indicators

    International Nuclear Information System (INIS)

    1975-01-01

    Recent years have witnessed significant advances in isotope techniques for identifying origins and for studying the behaviour of trace contaminants and pollutants of the environment under actual existing environmental conditions. Improvements in the supply of stable isotopes and their labelled compounds, instrumental analysis and information on stable or radioactive isotopic ratios of existing environmental contaminants as a function of origin or behaviour have provided relatively new tools for the environmental scientist. While variations in natural or existing environmental stable and radioactive nuclides could be regarded as 'background noise' in conventional tracer experiments they promised unique information about sources and behaviour to those who listened carefully. (author)

  6. Hot vacuum extraction-isotopic dilution mass spectrometry for determination of hydrogen isotopes in zircaloys

    International Nuclear Information System (INIS)

    Shi, Y.; Leeson, P.K.; Wilkin, D.; Britton, A.; Macleod, R.

    2016-01-01

    A hot vacuum extraction-isotope dilution mass spectrometry (HVE-IDMS) was studied for determination of hydrogen isotopes in zirconium metal and alloys as nuclear reactor materials. A theoretical assessment of the completeness of the extraction of hydrogen isotopes under the chosen condition was carried out based on the hydrogen and deuterium solubility data for zirconium. The optimal isotopic spiking condition for conventional IDMS was further explored for the special case IDMS where the isotope abundance of the samples is varied and non-natural. Applying the optimal conditions, the accurate IDMS determination was realized. The agreement between the measured values and the certified or prepared values of standard reference materials and homemade standard materials validate the method developed. (author)

  7. Studies of isotopic defined hydrogen beams scattering from Pd single-crystal surfaces

    International Nuclear Information System (INIS)

    Varlam, Mihai; Steflea, Dumitru

    2001-01-01

    An experimental investigation of hydrogen isotopes interaction with Pd single-crystal surface has been carried out using molecular beam technique. The energy dependence of the sticking probability and its relation with the trapping probability into the precursor state is studied by integrating the scattered angular distribution of hydrogen Isotopic defined beams from Pd (111) surface in the 40-400 K surface temperature range. The dependence has been evaluated by defining hydrogen molecular beams with different isotopic concentration - from the natural one to the 5% D/(D+H) ratio - and for different incident energies. The beam was directed onto a single-crystal Pd (111) surface. In the paper, we report the experimental results and some considerations related to it. (authors)

  8. Enhancing atom densities in solid hydrogen by isotopic substitution

    International Nuclear Information System (INIS)

    Collins, G.W.; Souers, P.C.; Mapoles, E.R.; Magnotta, F.

    1991-01-01

    Atomic hydrogen inside solid H 2 increases the energy density by 200 MegaJoules/m 3 , for each percent mole fraction stored. How many atoms can be stored in solid hydrogen? To answer this, we need to know: (1) how to produce and trap hydrogen atoms in solid hydrogen, (2) how to keep the atoms from recombining into the ground molecular state, and (3) how to measure the atom density in solid hydrogen. Each of these topics will be addressed in this paper. Hydrogen atoms can be trapped in solid hydrogen by co-condensing atoms and molecules, external irradiation of solid H 2 , or introducing a radioactive impurity inside the hydrogen lattice. Tritium, a heavy isotope of hydrogen, is easily condensed as a radioactive isotopic impurity in solid H 2 . Although tritium will probably not be used in future rockets, it provides a way of applying a large, homogenious dose to solid hydrogen. In all of the data presented here, the atoms are produced by the decay of tritium and thus knowing how many atoms are produced from the tritium decay in the solid phase is important. 6 refs., 6 figs

  9. Results of Am isotopic ratio analysis in irradiated MOX fuels

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Shin-ichi; Osaka, Masahiko; Mitsugashira, Toshiaki; Konno, Koichi [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center; Kajitani, Mikio

    1997-04-01

    For analysis of a small quantity of americium, it is necessary to separate from curium which has similar chemical property. As a chemical separation method for americium and curium, the oxidation of americium with pentavalent bismuth and subsequent co-precipitation of trivalent curium with BIP O{sub 4} were applied to analyze americium in irradiated MOX fuels which contained about 30wt% plutonium and 0.9wt% {sup 241}Am before irradiation and were irradiated up to 26.2GWd/t in the experimental fast reactor Joyo. The purpose of this study is to measure isotopic ratio of americium and to evaluate the change of isotopic ratio with irradiation. Following results are obtained in this study. (1) The isotopic ratio of americium ({sup 241}Am, {sup 242m}Am and {sup 243}Am) can be analyzed in the MOX fuels by isolating americium. The isotopic ratio of {sup 242m}Am and {sup 243}Am increases up to 0.62at% and 0.82at% at maximum burnup, respectively, (2) The results of isotopic analysis indicates that the contents of {sup 241}Am decreases, whereas {sup 242m}Am, {sup 243}Am increase linearly with increasing burnup. (author)

  10. Calcium isotope ratios in animal and human bone

    Science.gov (United States)

    Reynard, L. M.; Henderson, G. M.; Hedges, R. E. M.

    2010-07-01

    Calcium isotopes in tissues are thought to be influenced by an individual's diet, reflecting parameters such as trophic level and dairy consumption, but this has not been carefully assessed. We report the calcium isotope ratios (δ 44/42Ca) of modern and archaeological animal and human bone ( n = 216). Modern sheep raised at the same location show 0.14 ± 0.08‰ higher δ 44/42Ca in females than in males, which we attribute to lactation by the ewes. In the archaeological bone samples the calcium isotope ratios of the herbivorous fauna vary by location. At a single site, the archaeological fauna do not show a trophic level effect. Humans have lower δ 44/42Ca than the mean site fauna by 0.22 ± 0.22‰, and the humans have a greater δ 44/42Ca range than the animals. No effect of sex or age on the calcium isotope ratios was found, and intra-individual skeletal δ 44/42Ca variability is negligible. We rule out dairy consumption as the main cause of the lower human δ 44/42Ca, based on results from sites pre-dating animal domestication and dairy availability, and suggest instead that individual physiology and calcium intake may be important in determining bone calcium isotope ratios.

  11. Isotope exchange between gaseous hydrogen and uranium hydride powder

    International Nuclear Information System (INIS)

    Shugard, Andrew D.; Buffleben, George M.; Johnson, Terry A.; Robinson, David B.

    2014-01-01

    Highlights: • Isotope exchange between hydrogen gas and uranium hydride powder can be rapid and reversible. • Gas–solid exchange rate is controlled by transport within ∼0.7 μm hydride particles. • Gas chromatographic separation of hydrogen isotopes using uranium hydride is feasible. - Abstract: Isotope exchange between gaseous hydrogen and solid uranium hydride has been studied by flowing hydrogen (deuterium) gas through packed powder beds of uranium deuteride (hydride). We used a residual gas analyzer system to perform real-time analysis of the effluent gas composition. We also developed an exchange and transport model and, by fitting it to the experimental data, extracted kinetic parameters for the isotope exchange reaction. Our results suggest that, from approximately 70 to 700 kPa and 25 to 400 °C, the gas-to-solid exchange rate is controlled by hydrogen and deuterium transport within the ∼0.7 μm diameter uranium hydride particles. We use our kinetic parameters to show that gas chromatographic separation of hydrogen and deuterium using uranium hydride could be feasible

  12. Hydrogen isotopic spectral determination in inert gases with the use of light source with contracted discharge

    International Nuclear Information System (INIS)

    Nemets, V.M.; Solov'ev, A.A.

    1981-01-01

    Isotopic-spectral technique for hydrogen determination in helium, neon and argon is developed. It employs a contracted high-frequency discharge as a light source to decrease the distorting effect. of a dummy signal and the ''memory'' effect of the discharge tube. The discharge is realized in a quartz tube approximately 7 mm dia. and gas pressure in it approximately 6x10 4 Pa. The analysis technique comprises sampling of gas, dosed introduction of deuterium into the sample, selection of a mixture portion into the discharge tube, spectroscopic determination of hydrogen isotope ratio and calculation of the sought for hydrogen concentration. The lower boundary of the determined concentrations of hydrogen constitutes 7x10 - 5 , 2x10 - 4 and 4x10 - 4 volumetric per cent in helium, neon, and argon, respectively

  13. Heavy element stable isotope ratios. Analytical approaches and applications

    International Nuclear Information System (INIS)

    Tanimizu, Masaharu; Sohrin, Yoshiki; Hirata, Takafumi

    2013-01-01

    Continuous developments in inorganic mass spectrometry techniques, including a combination of an inductively coupled plasma ion source and a magnetic sector-based mass spectrometer equipped with a multiple-collector array, have revolutionized the precision of isotope ratio measurements, and applications of inorganic mass spectrometry for biochemistry, geochemistry, and marine chemistry are beginning to appear on the horizon. Series of pioneering studies have revealed that natural stable isotope fractionations of many elements heavier than S (e.g., Fe, Cu, Zn, Sr, Ce, Nd, Mo, Cd, W, Tl, and U) are common on Earth, and it had been widely recognized that most physicochemical reactions or biochemical processes induce mass-dependent isotope fractionation. The variations in isotope ratios of the heavy elements can provide new insights into past and present biochemical and geochemical processes. To achieve this, the analytical community is actively solving problems such as spectral interference, mass discrimination drift, chemical separation and purification, and reduction of the contamination of analytes. This article describes data calibration and standardization protocols to allow interlaboratory comparisons or to maintain traceability of data, and basic principles of isotope fractionation in nature, together with high-selectivity and high-yield chemical separation and purification techniques for stable isotope studies.

  14. Retention of hydrogen isotopes and helium in nickel

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Mitsumasa; Sato, Rikiya; Yamaguchi, Kenji; Yamawaki, Michio [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    In the present study, a thin foil of nickel was irradiated by H{sub 2}{sup +}, D{sub 2}{sup +} and He{sup +} to a fluence of 1.2-6.0x10{sup 20}/m{sup 2} using the TBTS (Tritium Beam Test System) apparatus. The thermal desorption spectroscopy (TDS) technique was employed to evaluate the total amount of retained hydrogen isotope and helium atoms in nickel. In the spectra, two peaks appeared at 440-585K and 720-735K for helium. Hydrogen isotopes irradiation after helium preirradiation were found to enhance the helium release and to decrease the peak temperatures. Helium irradiation after hydrogen isotopes preirradiation were found to enhance the helium release, but the peak temperature showed little difference from that without preirradiation. (author)

  15. Isotopic ratios in outbursting comet C/2015 ER61

    Science.gov (United States)

    Yang, Bin; Hutsemékers, Damien; Shinnaka, Yoshiharu; Opitom, Cyrielle; Manfroid, Jean; Jehin, Emmanuël; Meech, Karen J.; Hainaut, Olivier R.; Keane, Jacqueline V.; Gillon, Michaël

    2018-02-01

    Isotopic ratios in comets are critical to understanding the origin of cometary material and the physical and chemical conditions in the early solar nebula. Comet C/2015 ER61 (PANSTARRS) underwent an outburst with a total brightness increase of 2 magnitudes on the night of 2017 April 4. The sharp increase in brightness offered a rare opportunity to measure the isotopic ratios of the light elements in the coma of this comet. We obtained two high-resolution spectra of C/2015 ER61 with UVES/VLT on the nights of 2017 April 13 and 17. At the time of our observations, the comet was fading gradually following the outburst. We measured the nitrogen and carbon isotopic ratios from the CN violet (0, 0) band and found that 12C/13C = 100 ± 15, 14N/15N = 130 ± 15. In addition, we determined the 14N/15N ratio from four pairs of NH2 isotopolog lines and measured 14N/15N = 140 ± 28. The measured isotopic ratios of C/2015 ER61 do not deviate significantly from those of other comets.

  16. The use of carbon stable isotope ratios in drugs characterization

    Energy Technology Data Exchange (ETDEWEB)

    Magdas, D. A., E-mail: gabriela.cristea@itim-cj.ro; Cristea, G., E-mail: gabriela.cristea@itim-cj.ro; Bot, A., E-mail: gabriela.cristea@itim-cj.ro; Mirel, V., E-mail: gabriela.cristea@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania)

    2013-11-13

    Isotopic Ratio Mass Spectrometry (IRMS) is an effective toll to be used for drug product authentication. The isotopic composition could be used to assist in the differentiation between batches of drugs and assist in the identification of counterfeit materials on the market. Only two factors affect the isotopic ratios in pharmaceutical components: the isotopic composition of the raw materials and the synthetic processes performed upon them. Counterfeiting of pharmaceutical drugs threatens consumer confidence in drug products companies' economical well-being. In this preliminary study, the analyzed samples consist in two types of commercially available analgesics, which were purchases from Romanian pharmacies. Differences in δ{sup 13}C between batches from −29.7 to −31.6% were observed, demonstrating that this method can be used to differentiate among individual drug batches and subsequently identify counterfeits on the market. On the other hand, carbon isotopic ratios differences among producers were recorded, the variations being between −31.3 to −34.9% for the same type of analgesic, but from different manufactures.

  17. Hydrogen isotopic fractionation during crystallization of the terrestrial magma ocean

    Science.gov (United States)

    Pahlevan, K.; Karato, S. I.

    2016-12-01

    Models of the Moon-forming giant impact extensively melt and partially vaporize the silicate Earth and deliver a substantial mass of metal to the Earth's core. The subsequent evolution of the terrestrial magma ocean and overlying vapor atmosphere over the ensuing 105-6 years has been largely constrained by theoretical models with remnant signatures from this epoch proving somewhat elusive. We have calculated equilibrium hydrogen isotopic fractionation between the magma ocean and overlying steam atmosphere to determine the extent to which H isotopes trace the evolution during this epoch. By analogy with the modern silicate Earth, the magma ocean-steam atmosphere system is often assumed to be chemically oxidized (log fO2 QFM) with the dominant atmospheric vapor species taken to be water vapor. However, the terrestrial magma ocean - having held metallic droplets in suspension - may also exhibit a much more reducing character (log fO2 IW) such that equilibration with the overlying atmosphere renders molecular hydrogen the dominant H-bearing vapor species. This variable - the redox state of the magma ocean - has not been explicitly included in prior models of the coupled evolution of the magma ocean-steam atmosphere system. We find that the redox state of the magma ocean influences not only the vapor speciation and liquid-vapor partitioning of hydrogen but also the equilibrium isotopic fractionation during the crystallization epoch. The liquid-vapor isotopic fractionation of H is substantial under reducing conditions and can generate measurable D/H signatures in the crystallization products but is largely muted in an oxidizing magma ocean and steam atmosphere. We couple equilibrium isotopic fractionation with magma ocean crystallization calculations to forward model the behavior of hydrogen isotopes during this epoch and find that the distribution of H isotopes in the silicate Earth immediately following crystallization represents an oxybarometer for the terrestrial

  18. Development of Separation Materials Containing Palladium for Hydrogen Isotopes Separation

    International Nuclear Information System (INIS)

    Deng Xiaojun; Luo Deli; Qian Xiaojing

    2010-01-01

    Displacement chromatography (DC) is a ascendant technique for hydrogen isotopes separation. The performance of separation materials is a key factor to determine the separation effect of DC. At present,kinds of materials are researched, including palladium materials and non-palladium materials. It is hardly replaceable because of its excellent separation performance, although palladium is expensive. The theory of hydrogen isotopes separation using DC was introduced at a brief manner, while several palladium separation materials were expatiated in detail(Pd/K, Pd-Al 2 O 3 , Pd-Pt alloy). Development direction of separation materials for DC was forecasted elementarily. (authors)

  19. Applications of Isotope Ratio Mass Spectrometry in Sports Drug Testing Accounting for Isotope Fractionation in Analysis of Biological Samples.

    Science.gov (United States)

    Piper, Thomas; Thevis, Mario

    2017-01-01

    The misuse of anabolic-androgenic steroids (AAS) in sports aiming at enhancing athletic performance has been a challenging matter for doping control laboratories for decades. While the presence of a xenobiotic AAS or its metabolite(s) in human urine immediately represents an antidoping rule violation, the detection of the misuse of endogenous steroids such as testosterone necessitates comparably complex procedures. Concentration thresholds and diagnostic analyte ratios computed from urinary steroid concentrations of, e.g., testosterone and epitestosterone have aided identifying suspicious doping control samples in the past. These ratios can however also be affected by confounding factors and are therefore not sufficient to prove illicit steroid administrations. Here, carbon and, in rare cases, hydrogen isotope ratio mass spectrometry (IRMS) has become an indispensable tool. Importantly, the isotopic signatures of pharmaceutical steroid preparations commonly differ slightly but significantly from those found with endogenously produced steroids. By comparing the isotope ratios of endogenous reference compounds like pregnanediol to that of testosterone and its metabolites, the unambiguous identification of the urinary steroids' origin is accomplished. Due to the complex urinary matrix, several steps in sample preparation are inevitable as pure analyte peaks are a prerequisite for valid IRMS determinations. The sample cleanup encompasses steps such as solid phase or liquid-liquid extraction that are presumably not accompanied by isotopic fractionation processes, as well as more critical steps like enzymatic hydrolysis, high-performance liquid chromatography fractionation, and derivatization of analytes. In order to exclude any bias of the analytical results, each step of the analytical procedure is optimized and validated to exclude, or at least result in constant, isotopic fractionation. These efforts are explained in detail. © 2017 Elsevier Inc. All rights reserved.

  20. Cross contamination in dual inlet isotope ratio mass spectrometers

    NARCIS (Netherlands)

    Meijer, H.A.J.; Neubert, R.E.M.; Visser, G.H.

    2000-01-01

    Since the early days of geochemical isotope ratio mass spectrometry there has always been the problem of cross contamination, i.e. the contamination of the sample gas with traces of reference gas land vice versa) in a dual inlet system and the analyzer itself. This was attributable to valve leakages

  1. Lead isotope ratios in Japanese galena ores and archaeological objects

    International Nuclear Information System (INIS)

    Yamasaki, Kazuo; Murozumi, Masayo; Nakamura, Seiji; Hinata, Makoto; Yuasa, Mitsuaki.

    1978-01-01

    Lead isotope ratios 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, 208 Pb/ 204 Pb, 207 Pb/ 206 Pb and 208 Pb/ 206 Pb in Japanese galena ores and archaeological bronze objects were determined by a Hitachi RMU-6 mass spectrometer using a rhenium single filament as a surface ionization device. Basic experimental conditions including detection limit, fractionation effect, memory effect, etc. were examined, and the accuracy of determination was checked using the CIT shelf standard No. 1. Archaeological bronze objects were dissolved in nitric acid and lead was extracted by the dithizone method using specially purified reagents in a so-called clean laboratory. When 0.5 μg lead was loaded on the rhenium filament with phosphoric acid and silica gel as stabilizers, an ion current of 10 -13 -- 10 -15 A due to Pb + was obtained and maintained stable for several hours. Coefficients of variation found for the isotope ratios 207 Pb/ 206 Pb and 208 Pb/ 206 Pb were 0.1 -- 0.5%. Lead isotope ratios are given for 17 Japanese galena ores and for archaeological bronze objects such as bronze bells, halberds (Yayoi period), Horyuji pagoda spire (7th century), and Northern Sung coins (11th century). A close resemblance of the isotope ratios was found between Japanese galena ores and some Japanese bronze objects of the 7th century, suggesting the use of the former as raw materials of the latter. (auth.)

  2. Seawater calcium isotope ratios across the Eocene-Oligocene transition

    Science.gov (United States)

    Griffith, E.M.; Paytan, A.; Eisenhauer, A.; Bullen, T.D.; Thomas, E.

    2011-01-01

    During the Eocene-Oligocene transition (EOT, ca. 34 Ma), Earth's climate cooled significantly from a greenhouse to an icehouse climate, while the calcite (CaCO3) compensation depth (CCD) in the Pacific Ocean increased rapidly. Fluctuations in the CCD could result from various processes that create an imbalance between calcium (Ca) sources to, and sinks from, the ocean (e.g., weathering and CaCO3 deposition), with different effects on the isotopic composition of dissolved Ca in the oceans due to differences in the Ca isotopic composition of various inputs and outputs. We used Ca isotope ratios (??44/40Ca) of coeval pelagic marine barite and bulk carbonate to evaluate changes in the marine Ca cycle across the EOT. We show that the permanent deepening of the CCD was not accompanied by a pronounced change in seawater ??44/40Ca, whereas time intervals in the Neogene with smaller carbonate depositional changes are characterized by seawater ??44/40Ca shifts. This suggests that the response of seawater ??44/40Ca to changes in weathering fluxes and to imbalances in the oceanic alkalinity budget depends on the chemical composition of seawater. A minor and transient fluctuation in the Ca isotope ratio of bulk carbonate may reflect a change in isotopic fractionation associated with CaCO3 precipitation from seawater due to a combination of factors, including changes in temperature and/or in the assemblages of calcifying organisms. ?? 2011 Geological Society of America.

  3. Quantitative mass-spectrometric analysis of hydrogen helium isotope mixtures

    International Nuclear Information System (INIS)

    Langer, U.

    1998-12-01

    This work deals with the mass-spectrometric method for the quantitative analysis of hydrogen-helium-isotope mixtures, with special attention to fusion plasma diagnostics. The aim was to use the low-resolution mass spectrometry, a standard measuring method which is well established in science and industry. This task is solved by means of the vector mass spectrometry, where a mass spectrum is repeatedly measured, but with stepwise variation of the parameter settings of a quadruple mass spectrometer. In this way, interfering mass spectra can be decomposed and, moreover, it is possible to analyze underestimated mass spectra of complex hydrogen-helium-isotope mixtures. In this work experimental investigations are presented which show that there are different parameters which are suitable for the UMS-method. With an optimal choice of the parameter settings hydrogen-helium-isotope mixtures can be analyzed with an accuracy of 1-3 %. In practice, a low sensitivity for small helium concentration has to be noted. To cope with this task, a method for selective hydrogen pressure reduction has been developed. Experimental investigations and calculations show that small helium amounts (about 1 %) in a hydrogen atmosphere can be analyzed with an accuracy of 3 - 10 %. Finally, this work deals with the effects of the measuring and calibration error on the resulting error in spectrum decomposition. This aspect has been investigated both in general mass-spectrometric gas analysis and in the analysis of hydrogen-helium-mixtures by means of the vector mass spectrometry. (author)

  4. Advanced mass spectrometers for hydrogen-isotope analyses

    International Nuclear Information System (INIS)

    Chastagner, P.; Daves, H.L.; Hess, W.B.

    1982-01-01

    Two advanced mass spectrometers for the accurate analysis of mixtures of the hydrogen isotopes were evaluated by Du Pont personnel at the Savannah River Laboratory. One is a large double-focusing instrument with a resolution of 2000 at mass 4 and an abundance sensitivity of >100,000 for the HT-D 2 doublet. The second is a smaller, simpler, stigmatic focusing instrument with exceptionally high ion intensities (>1 x 10 - 9 A at 600 resolution and about 1 x 10 - 10 A at 1300 resolution) for high signal-to-noise ratios. Both instruments are computer controlled. Once a scan is started, peak switching, scanning, mass discrimination control, data collection, and data reduction are done without operator intervention. Utility routines control hysteresis effects and instrument calibration. A containment facility, with dual inlet systems and a standard distribution system, permits testing with tritium mixtures. Helium flow standards and tritium activity meters provide independent verification of the mass spectrometer calibrations. A recovery system prevents the release of tritium to the environment. The performance of the mass spectrometers was essentially equal under simulated process control conditions. Precision and accuracy for the D/T ratio was <0.5% (rel 2sigma limits). Performance factors were: sample equilibration <300 ppM; linearity within +-0.3%; and gas interference <0.1%. Mass discrimination was controlled reliably by the computers

  5. Factors determining the activity of catalysts of various chemical types in the oxidation of hydrogen. I. Oxidation and isotope exchange of hydrogen on cobalt monoxide-oxide

    International Nuclear Information System (INIS)

    Polgikh, L.Y.; Golodets, G.I.; Il'chenko, N.I.

    1985-01-01

    On the basis of data on the kinetics of the reaction 2H 2 + O 2 = 2H 2 O isotope exchange H 2 + D 2 = 2HD under the conditions of oxidative catalysis, and the kinetic isotope effect, a mechanism is proposed for the oxidation of hydrogen on cobalt monoxide-oxide. At low temperatures the reaction proceeds according to a mechanism of alternating reduction-reoxidation of the surface with the participation of hydrogen adsorbed in molecular form; at increased temperature and low P 02 /P /SUB H2/ ratios, a significant contribution to the observed rate is made by a mechanism including dissociative chemisorption of hydrogen

  6. A Time-Measurement System Based on Isotopic Ratios

    International Nuclear Information System (INIS)

    Vo, Duc T.; Karpius, P.J.; MacArthur, D.W.; Thron, J.L.

    2007-01-01

    A time-measurement system can be built based on the ratio of gamma-ray peak intensities from two radioactive isotopes. The ideal system would use a parent isotope with a short half-life decaying to a long half-life daughter. The activities of the parent-daughter isotopes would be measured using a gamma-ray detector system. The time can then be determined from the ratio of the activities. The best-known candidate for such a system is the 241 Pu- 241 Am parent-daughter pair. However, this 241 Pu- 241 Am system would require a high-purity germanium detector system and sophisticated software to separate and distinguish between the many gamma-ray peaks produced by the decays of the two isotopes. An alternate system would use two different isotopes, again one with a short half-life and one with a half-life that is long relative to the other. The pair of isotopes 210 Pb and 241 Am (with half-lives of 22 and 432 years, respectively) appears suitable for such a system. This time-measurement system operates by measuring the change in the ratio of the 47-keV peak of 210 Pb to the 60-keV peak of 241 Am. For the system to work reasonably well, the resolution of the detector would need to be such that the two gamma-ray peaks are well separated so that their peak areas can be accurately determined using a simple region-of-interest (ROI) method. A variety of detectors were tested to find a suitable system for this application. The results of these tests are presented here.

  7. Laser separation of isotopes of hydrogen

    International Nuclear Information System (INIS)

    Dave, S.M.; Ghosh, S.K.; Sadhukhan, H.K.

    1980-01-01

    Laser isotope separation technique is explained and various methods based on the technique are discussed in detail. Requirements of any laser isotope separation method to be acceptable for the production of heavy water are mentioned and economic viability of this process for heavy water production is examined. Investigations carried out to use this technique for deuterium separation using methanol, formaldehyde, propynal, 2,2,-dichloro-1-1-1,-trifluoroethane (Freon 123), polyvinyl chloride and fluoroform-d are reviewed. (M.G.B.)

  8. Determination of strontium and lead isotope ratios of grains using high resolution inductively coupled plasma mass spectrometer with single collector

    International Nuclear Information System (INIS)

    Shinozaki, Miyuki; Ariyama, Kaoru; Kawasaki, Akira; Hirata, Takafumi

    2010-01-01

    A method for determining strontium and lead isotope ratios of grains was developed. The samples investigated in this study were rice, barley and wheat. The samples were digested with nitric acid and hydrogen peroxide, and heated in a heating block. Strontium and lead were separated from the matrix by adding an acid digested solution into a column packed with Sr resin, which has selectivity for the absorption of strontium and lead. Strontium and lead isotope ratios were determined using a high-resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) with a single collector. The intraday relative standard deviations of 87 Sr/ 86 Sr and lead isotope ratios ( 204 Pb/ 206 Pb, 207 Pb/ 206 Pb, 208 Pb/ 206 Pb) by HR-ICP-MS measurements were < 0.06% and around 0.1%, respectively. This method enabled us to determine strontium and lead isotope ratios in two days. (author)

  9. Study of peculiarities of hydrogen isotopes mixture permeation through low activated steel F82H

    International Nuclear Information System (INIS)

    Kenzhin, Ye.A.; Tazhibayeva, I.L; Kulsartov, T.V.; Shestakov, V.P.; Chikhray, Ye.V.; Afanasev, S.E.; Zheldak, Yu.L.

    2003-01-01

    Full text: The problem of diffusion tritium leakage through blanket materials of future fusion device makes some constructive difficulties concerned with protection of personnel and environment and also with losses of tritium, which is planned to be used in the same device. One of the little-studied problems in the tritium leakage process in Fusion Power Plant is that in fact tritium will penetrate through materials while other hydrogen isotopes are present. These are deuterium and hydrogen which always are present in metals. Therefore, for evaluation of tritium leakage in future Fusion Power Plant under such conditions it is necessary to have experimental data about permeation of these hydrogen isotopes through the structure materials.One of proposed structure materials of fusion reactor blanket is low activated steel F82H. The experiment results on evaluation of .hydrogen, deuterium and its mixture interaction parameters with steel F82H are shown in this work. The tests were carried out within temperature range 273-973 K under inlet hydrogen pressure of 100-2000 Pa. Diffusivity, deuterium and hydrogen permeation constants for low activated steel F82H was determined from experiment results. Those experimental results were used for created phenomenology model which describes hydrogen isotope penetration through tube sample from hydrogen isotopes mixture. That model was used so determining the ratios of desorption rates (D-D, D-H, H-H) on outlet side of sample. Using of so obtained results, we can correctly evaluate, the titanium leakage from blanket of fusion machine which will be constructed using low activated steel F82H

  10. Finite mixture models for the computation of isotope ratios in mixed isotopic samples

    Science.gov (United States)

    Koffler, Daniel; Laaha, Gregor; Leisch, Friedrich; Kappel, Stefanie; Prohaska, Thomas

    2013-04-01

    Finite mixture models have been used for more than 100 years, but have seen a real boost in popularity over the last two decades due to the tremendous increase in available computing power. The areas of application of mixture models range from biology and medicine to physics, economics and marketing. These models can be applied to data where observations originate from various groups and where group affiliations are not known, as is the case for multiple isotope ratios present in mixed isotopic samples. Recently, the potential of finite mixture models for the computation of 235U/238U isotope ratios from transient signals measured in individual (sub-)µm-sized particles by laser ablation - multi-collector - inductively coupled plasma mass spectrometry (LA-MC-ICPMS) was demonstrated by Kappel et al. [1]. The particles, which were deposited on the same substrate, were certified with respect to their isotopic compositions. Here, we focus on the statistical model and its application to isotope data in ecogeochemistry. Commonly applied evaluation approaches for mixed isotopic samples are time-consuming and are dependent on the judgement of the analyst. Thus, isotopic compositions may be overlooked due to the presence of more dominant constituents. Evaluation using finite mixture models can be accomplished unsupervised and automatically. The models try to fit several linear models (regression lines) to subgroups of data taking the respective slope as estimation for the isotope ratio. The finite mixture models are parameterised by: • The number of different ratios. • Number of points belonging to each ratio-group. • The ratios (i.e. slopes) of each group. Fitting of the parameters is done by maximising the log-likelihood function using an iterative expectation-maximisation (EM) algorithm. In each iteration step, groups of size smaller than a control parameter are dropped; thereby the number of different ratios is determined. The analyst only influences some control

  11. Hydrogen isotopes identification with the electromagnetic calorimeter TAPS

    International Nuclear Information System (INIS)

    Matulewicz, T.; Aphecetche, L.; Charbonnier, Y.; Delagrange, H.; Martinez, G.; Schutz, Y.; Marques, F.M.; Diaz, J.; and others.

    1996-01-01

    A new method has been developed to identify protons and more generally charged massive particles, like charged pions, hydrogen isotopes and heavier particles reaching the TAPS detector. The method was tested on events from the reaction Ar+Ca at 180 A.MeV. (K.A.)

  12. Cascades for hydrogen isotope separation using metal hydrides

    International Nuclear Information System (INIS)

    Hill, F.B.; Grzetic, V.

    1982-01-01

    Designs are presented for continuous countercurrent hydrogen isotope separation cascades based on the use of metal hydrides. The cascades are made up of pressure swing adsorption (PSA) or temperature swing adsorption (TSA) stages. The designs were evolved from consideration of previously conducted studies of the separation performance of four types of PSA and TSA processes

  13. Cascades for hydrogen isotope separation using metal hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Hill, F B; Grzetic, V [Brookhaven National Lab., Upton, NY (USA)

    1983-02-01

    Designs are presented for continuous countercurrent hydrogen isotope separation cascades based on the use of metal hydrides. The cascades are made up of pressure swing adsorption (PSA) or temperature swing adsorption (TSA) stages. The designs were evolved from consideration of previously conducted studies of the separation performance of four types of PSA and TSA processes.

  14. Quantum mechanical calculation of diffusion of hydrogen isotopes in vanadium

    International Nuclear Information System (INIS)

    Yoshinari, Osamu

    2013-01-01

    Highlights: • Diffusion of H isotopes in V was investigated with a quantum mechanical calculation. • Calculated diffusion coefficients quantitatively agreed with the experimental data. • H in V jumps via quantum mechanical tunneling between the two tetrahedral sites. • H tunneling between ground states is dominant at low temperatures. • H tunneling between exited states becomes important at higher temperatures. -- Abstract: Diffusion of hydrogen isotopes in vanadium was investigated by a quantum mechanical calculation. Wave functions and the corresponding eigen energies (E) for hydrogen isotopes were obtained as a function of hydrogen position along the diffusion path (ξ) by solving the three dimensional Schrödinger equation. Hydrogen potential was calculated by using a first principles method with a nudged elastic band technique. By analyzing the E–ξ curves, the tunneling matrix elements were obtained for the coincidence states between two neighboring tetrahedral sites. It was clarified that the tunneling between ground states was dominant at low temperatures, whereas the contribution of that between the first exited states becomes larger at higher temperatures. The transition temperature of the dominant tunneling decreases with the isotope mass. The calculated temperature dependence of the diffusion for the V–H system quantitatively agreed with the experimental data in the literature, although those for the V–D and –T systems were somewhat underestimated

  15. Hydrogen, deuterium, and tritium isotope exchange experiments in JET

    Energy Technology Data Exchange (ETDEWEB)

    Horton, L.D.; Andrew, P.; Bracco, G.; Conroy, S.; Corti, S.; Ehrenberg, J.; Goodall, D.H.J.; Jarvis, O.N.; Lomas, P.; Loughlin, M.; Peacock, A.T.; Saibene, G.; Sadler, G.; Sartori, R.; Stamp, M.F.; Thomas, P.R.; Belle, P. van (JET Joint Untertaking, Abingdon, Oxfordshire (United Kingdom))

    1992-12-01

    Isotope exchange experiments have been performed in JET using hydrogen, deuterium, and, in the recent preliminary tritium experiment (PTE), tritium. The rate of change-over from one isotope to another involves two quite different time constants. We have modelled this behaviour using a multireservoir model which splits the accessible hydrogenic particles into two groups, each having a different rate of exchange of particles with the plasma. By applying this model to the sequence of discharges during and after the PTE, we can determine the parameters in the model. The resulting fit also gives a good representation of hydrogen/deuterium change-over experiments, indicating that the tritium behaves in the same manner as other hydrogen isotopes, at least as far as recycling is concerned. Discrepancies between the model and the actual measurements of tritium recovery after the PTE lead us to conclude that isotope exchange processes resulting from collisions of molecules with the vessel walls play a significant role in spreading tritrium around the machine. (orig.).

  16. Hydrogen-isotopic composition of some hydrous manganese minerals

    International Nuclear Information System (INIS)

    Hariya, Y.; Tsutsumi, M.

    1981-01-01

    Initial data on the hydrogen-isotopic compositions in hydrous Mn minerals from various occurrences fall in a wide range from -298 to -84per thousand, relative to SMOW. deltaD-values of todorokite and cryptomelane from Tertiary deposits show -89 and -150per thousand. 10 A-manganite and delta-MnO 2 from deep-sea nodules have relatively restricted deltaD-values ranging from -96 to -84per thousand. The deltaD-values for manganese bog ores from recent hot springs show almost -105per thousand. It is recognized that the isotopic values obtained for the deep-sea nodules and recent bog ores are slightly different ranged. Manganite and groutite are unique in their hydrogen-isotopic compositions, having the most depleted deltaD-values ranging from -298 to -236per thousand. MnO(OH) minerals are more deuterium-depleted hydrous minerals than any other hydrothermal minerals from various ore deposits. Hydrogen-isotope fractionation factors between manganite and water were experimentally determined to be 0.7894, 0.7958 and 0.8078 at 150 0 , 200 0 and 250 0 C respectively. The present experimental results indicate that if manganites were formed at temperatures below 250 0 C, under isotopic equilibrium conditions most of the manganite mineralization in the Tertiary manganese deposits must have precipitated from meteoric hydrothermal solutions. (Auth.)

  17. Study on atmospheric hydrogen enrichment by cryopump method and isotope separation by gas chromatography

    International Nuclear Information System (INIS)

    Taniyama, Yuki; Momoshima, Noriyuki

    2001-01-01

    To obtain the information of source of atmospheric hydrogen tritium an analysis of tritium isotopes is thought to be effective. So an atmospheric hydrogen enrichment apparatus and a cryogenic gas chromatographic column were made. Experiments were carried out to study the performance of cryopump to enrich atmospheric hydrogen and the column to separate hydrogen isotopes that obtained by cryopump method. The cryopump was able to process about 1000 1 atmosphere and the column was able to separate hydrogen isotopes with good resolution. (author)

  18. An analytical system for the measurement of stable hydrogen isotopes in ambient volatile organic compounds

    Science.gov (United States)

    Meisehen, T.; Bühler, F.; Koppmann, R.; Krebsbach, M.

    2015-10-01

    Stable isotope measurements in atmospheric volatile organic compounds (VOCs) are an excellent tool to analyse chemical and dynamical processes in the atmosphere. While up to now isotope studies of VOCs in ambient air have mainly focussed on carbon isotopes, we herein present a new measurement system to investigate hydrogen isotope ratios in atmospheric VOCs. This system, consisting of a gas chromatography pyrolysis isotope ratio mass spectrometer (GC-P-IRMS) and a pre-concentration system, was thoroughly characterised using a VOC test mixture. A precision of better than 9 ‰ (in δ 2H) is achieved for n-pentane, 2-methyl-1,3-butadiene (isoprene), n-heptane, 4-methyl-pentane-2-one (4-methyl-2-pentanone), methylbenzene (toluene), n-octane, ethylbenzene, m/p-xylene and 1,2,4-trimethylbenzene. A comparison with independent measurements via elemental analysis shows an accuracy of better than 9 ‰ for n-pentane, n-heptane, 4-methyl-2-pentanone, toluene and n-octane. Above a minimum required pre-concentrated compound mass the obtained δ 2H values are constant within the standard deviations. In addition, a remarkable influence of the pyrolysis process on the isotope ratios is found and discussed. Reliable measurements are only possible if the ceramic tube used for the pyrolysis is sufficiently conditioned, i.e. the inner surface is covered with a carbon layer. It is essential to verify this conditioning regularly and to renew it if required. Furthermore, influences of a necessary H3+ correction and the pyrolysis temperature on the isotope ratios are discussed. Finally, the applicability to measure hydrogen isotope ratios in VOCs at ambient levels is demonstrated with measurements of outside air on 5 different days in February and March 2015. The measured hydrogen isotope ratios range from -136 to -105 ‰ forn-pentane, from -86 to -63 ‰ for toluene, from -39 to -15 ‰ for ethylbenzene, from -99 to -68 ‰ for m/p-xylene and from -45 to -34 ‰ for o-xylene.

  19. High precision isotopic ratio analysis of volatile metal chelates

    International Nuclear Information System (INIS)

    Hachey, D.L.; Blais, J.C.; Klein, P.D.

    1980-01-01

    High precision isotope ratio measurements have been made for a series of volatile alkaline earth and transition metal chelates using conventional GC/MS instrumentation. Electron ionization was used for alkaline earth chelates, whereas isobutane chemical ionization was used for transition metal studies. Natural isotopic abundances were determined for a series of Mg, Ca, Cr, Fe, Ni, Cu, Cd, and Zn chelates. Absolute accuracy ranged between 0.01 and 1.19 at. %. Absolute precision ranged between +-0.01-0.27 at. % (RSD +- 0.07-10.26%) for elements that contained as many as eight natural isotopes. Calibration curves were prepared using natural abundance metals and their enriched 50 Cr, 60 Ni, and 65 Cu isotopes covering the range 0.1-1010.7 at. % excess. A separate multiple isotope calibration curve was similarly prepared using enriched 60 Ni (0.02-2.15 at. % excess) and 62 Ni (0.23-18.5 at. % excess). The samples were analyzed by GC/CI/MS. Human plasma, containing enriched 26 Mg and 44 Ca, was analyzed by EI/MS. 1 figure, 5 tables

  20. Carbon isotope ratios in field Population II giant stars

    International Nuclear Information System (INIS)

    Sneden, C.; Pilachowski, C.A.; Vandenberg, D.A.; Kitt Peak National Observatory, Tucson, AZ; Victoria Univ., Canada)

    1986-01-01

    Carbon isotope ratios have been derived from high-resolution spectra of the CH G-band in 15 very metal-poor Population II giant stars and two similar dwarf stars. Many of the giants possess very low C-12/C-13 ratios, some approaching the CN cycle equilibrium value. The metal-poor dwarfs do not have detectable CH-13 features; thus the low carbon isotope ratios in the giants probably are due to their internal evolutions. These results strongly support the idea that at least part of the anomalously low C/N values in Population II giants arises from very efficient mixing of their envelopes into the CN cycle burning layers. Detailed calculations of the expected CNO surface abundances in Population II giants in different evolutionary states have been performed. These computations demonstrate that the observed carbon isotope ratios cannot be produced during the first dredge-up mixing phases in low-mass, low metal abundance stars. Numerical experiments show that theoretical and observational results can be brought into agreement with artificially induced extra mixing. An agent to provoke this additional mixing has not been identified with certainty yet, although internal stellar rotation is a promising candidate. 63 references

  1. Lead isotope ratios of ancient Chinese and Japanese glasses

    International Nuclear Information System (INIS)

    Yamasaki, Kazuo; Murozumi, Masayo; Nakamura, Seiji; Yuasa, Mitsuaki; Watarai, Motohiko.

    1980-01-01

    Lead isotope ratios of 29 archaeological glass samples (5 samples excavated in China, 10 samples excavated in Japan, and 14 samples made in Japan) were determined by surface ionization mass spectrometry with a HITACHI RMU-6 spectrometer. Of these glass samples, 28 were made of high lead glass, and one, of alkali-lime glass. Glass samples were decomposed in a mixture of hydrofluoric and nitric acids, and lead was separated from other elements by extraction with dithizone-chloroform. The lead nitrate solution thus prepared (corresponding to 0.5 μg Pb) was loaded on the rhenium single filament. The coefficients of variation of the determined ratios, 207 Pb/ 206 Pb and 208 Pb/ 206 Pb, were 0.1 -- 0.3%. Among the glasses excavated in Japan, some samples of the Yayoi period (ca. 3 rd C. B.C. -- ca. 3 rd C. A.D.) contained a large amount of barium in addition to lead, and resembled closely Chinese pre-Han glasses not only in chemical compositions, but also in lead isotope ratios. This means that pre-Han glasses were brought to Japan and then re-cast into glass beads characteristic of Japan. The lead isotope ratios of the glasses were compared with those of Chinese (2 samples), Korean (2) and Japanese (17) galena orea, and it was found that 12 glass beads made in the 8th century at Nara and 2 fine glass tubes made at Saga in the 18 th -- 19 th centuries showed similar lead isotope ratios with those of the Japanese galena ores. Consequently it is considered that the Japanese galena ores were already used as one of raw materials at manufacturing of these glass beads in ancient centuries. (author)

  2. MAGNESIUM ISOTOPE RATIOS IN ω CENTAURI RED GIANTS

    International Nuclear Information System (INIS)

    Da Costa, G. S.; Norris, John E.; Yong, David

    2013-01-01

    We have used the high-resolution observations obtained at the Anglo-Australian Telescope with Ultra-High Resolution Facility (R ∼ 100,000) and at Gemini-S with b-HROS (R ∼ 150,000) to determine magnesium isotope ratios for seven ω Cen red giants that cover a range in iron abundance from [Fe/H] = –1.78 to –0.78 dex, and for two red giants in M4 (NGC 6121). The ω Cen stars sample both the ''primordial'' (i.e., O-rich, Na- and Al-poor) and the ''extreme'' (O-depleted, Na- and Al-rich) populations in the cluster. The primordial population stars in both ω Cen and M4 show ( 25 Mg, 26 Mg)/ 24 Mg isotopic ratios that are consistent with those found for the primordial population in other globular clusters with similar [Fe/H] values. The isotopic ratios for the ω Cen extreme stars are also consistent with those for extreme population stars in other clusters. The results for the extreme population stars studied indicate that the 26 Mg/ 24 Mg ratio is highest at intermediate metallicities ([Fe/H] 26 Mg in the extreme population stars is notably higher than that of 25 Mg, in contrast to model predictions. The 25 Mg/ 24 Mg isotopic ratio in fact does not show any obvious dependence on either [Fe/H] or [Al/Fe] nor, intriguingly, any obvious difference between the primordial and extreme population stars.

  3. Preparation of Pt-PTFE hydrophobic catalyst for hydrogen-water isotope exchange

    International Nuclear Information System (INIS)

    Li Junhua; Kang Yi; Han Yande; Ruan Hao; Dou Qincheng; Hu Shilin

    2001-01-01

    The hydrophobic catalyst used in the hydrogen-water isotope exchange is prepared with Pt as the active metal, PTFE as the hydrophobic material, active carbon or silicon dioxide as the support. The isotope catalytic exchange reaction between hydrogen and water is carried out in the trickle bed and the effects of different carriers, mass fraction of Pt and PTFE on the catalytic activity are discussed. The experimental results show that the activity of Pt-C-PTFE hydrophobic catalyst with the ratio between PTFE and Pt-C from 1 to 2 is higher than other kinds of catalysts and the overall volume transfer coefficient is increased with the increasing of the hydrogen flow rate and reaction temperature

  4. Ratio of dialytic coefficients of hydrogen and tritium in permeation through palladium alloy film

    International Nuclear Information System (INIS)

    Fujita, Haruyuki; Fujita, Kunio; Sakamoto, Hiroshi; Higashi, Kunio; Okada, Sakae.

    1982-01-01

    The dialytic coefficient for hydrogen is especially large in palladium and its alloys. Recently, with the research on fusion reactors, the dialytic coefficient of tritium permeating through solids and its isotopic effect have been the object of interest. The ratio of the dialytic coefficients of tritium and hydrogen has been usually assumed to be 3. The measurement of the dialytic coefficient in solids using pure tritium is practically difficult. Therefore, the authors carried out the experiment to determine the ratio of the dialytic coefficients of pure T 2 and pure H 2 by permeating the mixed gas of T and H through Pd-Au-Ag alloy. The mixed hydrogen gas was filled in a separation cell containing a palladium alloy tube, and the separation factor of tritium and hydrogen was measured by changing pressure, flow rate and temperature. The separation factor depends mainly on the relative dialytic coefficients of tritium and hydrogen, therefore, the ratio of dialytic coefficients can be determined by the simple analysis of the experimental results. This experimental method is suitable to determine the relative value of dialytic coefficients, and the obtained ratio was about 2.1. (Kako, I.)

  5. Adsorption methods for hydrogen isotope storage on zeolitic sieves

    International Nuclear Information System (INIS)

    Cristescu, Ioana; Cristescu, Ion; Vasut, F.; Brad, S.; Lazar, A.

    2001-01-01

    For hydrogen isotope separation, adsorption molecular sieves and active carbon were used. Adsorption process proceeds at liquid nitrogen and liquid hydrogen temperatures. Commercial zeolites have the same proprieties with natural zeolites, but they have a regular pore structure. They also have affinity for molecules of different size with defined shapes. Experimental results obtained at liquid nitrogen temperature (77.4 K) and liquid hydrogen revealed the efficient behaviour of the active carbon and zeolitic sieves for hydrogen isotopes temporary storage. We study adsorption of the synthetic zeolites in a wide range of temperatures and pressures and we used the molecular sieves 4A, 5A and active carbon. The 4A and 5A zeolites have a tridimensional structure with 11.4 A diameter. When the hydration water is eliminated, the material keeps a porous structure. The porous volume represents 45% from the zeolite mass for 4A and 5A sieves. The activation temperature of the zeolite and the carbon is very important for obtaining a high adsorption capacity. If the temperature used for activation is low, the structural water will be not eliminated and the adsorption capacity will be low. The excessive temperature will destroy the porous structure. The adsorption capacity for the hydrogen isotopes was calculated with the relation: A = V ads /m (cm 3 /g). The adsorption capacity and efficiency for the adsorbent materials, are given. Physical adsorption process of the hydrogen isotopes was carried out at liquid nitrogen temperature. The flux gas used in the adsorption system is composed of dry deuterium and protium. This mixture is cooled in liquid nitrogen and then is passed to the adsorbent getter at the same temperature (77.4 K). The gas flux in the adsorbent getter is 5 and 72 l/h (which correspond to 0.008 and 0.134 discharge velocity, respectively). (authors)

  6. Plutonium isotopes/137Cs activity ratios for soil in Montenegro

    International Nuclear Information System (INIS)

    Antovic, N. M.; Vukotic, P.; Svrkota, N.; Andrukhovich, S.K.

    2011-01-01

    Plutonium isotopes/ 137 Cs activity ratios were determined for six soil samples from Montenegro, using the results of alpha-spectrometric measurements of 239+240 Pu and 238 Pu, as well as gamma-spectrometric cesium measurements. An average 239+240 Pu/ 137 Cs activity ratio is found to be 0.02, as the 238 Pu/ 137 Cs and 238 Pu/ 239+240 Pu one - 0.0006 and 0.03, respectively. It follows from the results that the source of plutonium in Montenegro soil is nuclear weapon testing during the fifties and sixties of the twentieth century. On the other hand, there is a contribution of the accident at the Chernobyl nuclear power plant to the soil contamination with 137 Cs isotope. [sr

  7. Measurement of boron isotope ratios in groundwater studies

    International Nuclear Information System (INIS)

    Porteous, N.C.; Walsh, J.N.; Jarvis, K.E.

    1995-01-01

    Boron is present at low levels in groundwater and rainfall in the UK, ranging between 2 and 200 ng ml -1 . A sensitive technique has been developed using inductively coupled plasma mass spectrometry (ICP-MS) to measure boron isotope ratios at low concentrations with a precision (s r ) of between 0.1 and 0.2%. Samples were evaporated to increase elemental boron concentrations to 200 ng ml -1 and interfering matrix elements were removed by an adapted cation-exchange separation procedure. The validity of measuring boron isotopic ratios by ICP-MS at this concentration level is discussed in relation to the theoretical instrument precision attainable based on counting statistics. (author)

  8. Separation of hydrogen isotope by hydrogen-water exchange

    International Nuclear Information System (INIS)

    Isomura, Shohei; Kaetsu, Hayato; Nakane, Ryohei

    1979-01-01

    The deuterium exchange reaction between gaseous hydrogen and liquid water is studied by use of three kinds of trickle bed exchange columns packed with hydrophobic catalysts supporting platinum. All columns have the effective lengths of 30 cm. They are 17 mm, 30 mm, and 95 mm in diameters, respectively. The separation experiments are carried out by the once-through methods. The separation efficiencies of the columns are evaluated by the parameters such as the height equivalent to a theoretical plate (H. E. T. P.) and the mass transfer co-efficient. It is found that the operating condition of the exchange column is optimum when the superficial hydrogen flow velocity is 0.3 m/sec. (author)

  9. Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples

    NARCIS (Netherlands)

    Godin, Jean-Philippe; Breuillé, Denis; Obled, Christiane; Papet, Isabelle; Schierbeek, Henk; Hopfgartner, Gérard; Fay, Laurent-Bernard

    2008-01-01

    On-line gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is commonly used to measure isotopic ratios at natural abundance as well as for tracer studies in nutritional and medical research. However, high-precision (13)C isotopic enrichment can also be measured by liquid

  10. Isotope ratios and chemical fractionation of CO in Lynds 134

    International Nuclear Information System (INIS)

    Dickman, R.L.; Langer, W.D.

    1977-01-01

    Mahoney, McCutcheon and Shuter (1976) reported observations of the J = 1 → 0 transition of three isotopes of CO in the dust cloud Lynds 134 using the 4.6 m telescope at Aerospace Corporation. In this paper a new observation of 12 C 17 O is discussed and the question of the ratio 13 C 16 O/ 12 C 18 O across the dust cloud is considered further. (Auth.)

  11. Steroid isotopic standards for gas chromatography-combustion isotope ratio mass spectrometry (GCC-IRMS).

    Science.gov (United States)

    Zhang, Ying; Tobias, Herbert J; Brenna, J Thomas

    2009-03-01

    Carbon isotope ratio (CIR) analysis of urinary steroids using gas chromatography-combustion isotope ratio mass spectrometry (GCC-IRMS) is a recognized test to detect illicit doping with synthetic testosterone. There are currently no universally used steroid isotopic standards (SIS). We adapted a protocol to prepare isotopically uniform steroids for use as a calibrant in GCC-IRMS that can be analyzed under the same conditions as used for steroids extracted from urine. Two separate SIS containing a mixture of steroids were created and coded CU/USADA 33-1 and CU/USADA 34-1, containing acetates and native steroids, respectively. CU/USADA 33-1 contains 5alpha-androstan-3beta-ol acetate (5alpha-A-AC), 5alpha-androstan-3alpha-ol-17-one acetate (androsterone acetate, A-AC), 5beta-androstan-3alpha-ol-11, 17-dione acetate (11-ketoetiocholanolone acetate, 11k-AC) and 5alpha-cholestane (Cne). CU/USADA 34-1 contains 5beta-androstan-3alpha-ol-17-one (etiocholanolone, E), 5alpha-androstan-3alpha-ol-17-one (androsterone, A), and 5beta-pregnane-3alpha, 20alpha-diol (5betaP). Each mixture was prepared and dispensed into a set of about 100 ampoules using a protocol carefully designed to minimize isotopic fractionation and contamination. A natural gas reference material, NIST RM 8559, traceable to the international standard Vienna PeeDee Belemnite (VPDB) was used to calibrate the SIS. Absolute delta(13)C(VPDB) and Deltadelta(13)C(VPDB) values from randomly selected ampoules from both SIS indicate uniformity of steroid isotopic composition within measurement reproducibility, SD(delta(13)C)<0.2 per thousand. This procedure for creation of isotopic steroid mixtures results in consistent standards with isotope ratios traceable to the relevant international reference material.

  12. Impurity effects of hydrogen isotope retention on boronized wall in LHD

    International Nuclear Information System (INIS)

    Oya, Yasuhisa; Okuno, Kenji; Ashikawa, Naoko; Nishimura, Kiyohiko; Sagara, Akio

    2010-11-01

    The impurity effect on hydrogen isotopes retention in the boron film deposited in LHD was evaluated by means of XPS and TDS. It was found that the impurity concentrations in boron film were increased after H-H main plasma exposure in LHD. The ratio of hydrogen retention trapped by impurity to total hydrogen retention during H-H main plasma exposure was reached to 70%, although that of deuterium retention by impurity in D 2 + implanted LHD-boron film was about 35%. In addition, the dynamic chemical sputtering of hydrogen isotopes with impurity as the form of water and / or hydrocarbons was occurred by energetic hydrogen isotopes irradiation. It was expected that the enhancement of impurity concentration during plasma exposure in LHD would induce the dynamic formation of volatile molecules and their re-emission to plasma. These facts would prevent stable plasma operation in LHD, concluding that the dynamic impurity behavior in boron film during plasma exposure is one of key issues for the steady-state plasma operation in LHD. (author)

  13. Proposed configuration for ITER hydrogen isotope separation system (ISS)

    International Nuclear Information System (INIS)

    Lazar, A.; Brad, S.; Sofalca, N.; Vijulie, M.; Cristescu, I.; Doer, L; Wurster, W.

    2008-01-01

    Full text: The isotope separation system utilizes cryogenic distillation and catalytic reaction for isotope exchange to separate elemental hydrogen isotope gas mixtures. The ISS shall separate hydrogen isotope mixtures from two sources to produce up to five different products. These are: protium, effluent for discharge to the atmosphere, deuterium for fuelling, deuterium for NB injector (NBI) source gas, 50 % and 90% T fuelling streams. The concept of equipment 3D layout for the ISS main components were developed using the Part Design, Assembly Design, Piping Design, Equipment Arrangement and Plant Layout application from CATIA V5. The 3D conceptual layouts for ISS system were created having as reference the DDD -32-B report, the drawings 0028.0001.2D. 0100. R 'Process Flow Diagram'; 0029.0001.2D. 0200.R 'Process Instrumentation Diagram -1' (in the cold box); 0030.0001.2D. 0100. R 'Process Instrumentation Diagram -2' (in the hard shell confinement) and imputes from TLK team. The main components designed for ISS are: ISS cold box system (CB) with cryogenic distillation columns (CD) and recovery heat exchangers (HX), ISS hard shell containment (HSC) system with metals bellow pumps (MB) and chemical equilibrators (RC), valve box system, instrumentation box system, vacuum system and hydrogen expansion vessels. Work related to these topics belongs to the contract FU06-CT-2006-00508 (EFDA 06-1511) from the EFDA Technology Workprogramm 2006 and was done in collaboration with FZK Association team during the period January 2007 - September 2008. (authors)

  14. Ratio of the dose factors of the isotopes of iodine

    International Nuclear Information System (INIS)

    Papadopoulos, D.; Thomas, P.

    1977-12-01

    The ratio of dose factors occurring during inhalation and ingestion to the respective dose factors of I-129 is calculated for the isotopes of I-123 to I-126 and I-129 to I-135. All the dose factors refer to the thyroid as the critical organ. A distinction is made between adults and infants up to 1 year of age. To calculate the ratios only the effective energies and the effective half-lives in the human body and on grass are required. Most of the data have been taken from the literature. The effective energies of I-123 and I-125 have been calculated as examples. (orig.) [de

  15. Hydrogen isotope exchange reaction rates in tritium, hydrogen and deuterium mixed gases

    International Nuclear Information System (INIS)

    Uda, Tatsuhiko

    1992-01-01

    Hydrogen isotope exchange reaction rates in H 2 +T 2 , D 2 +T 2 and H 2 +D 2 +T 2 mixed gases, as induced by tritium decay and beta radiation, were experimentally measured by laser Raman spectrometry. Initially a glass cell was filled with T 2 gas to a pressure of 30-40 kPa, and an equivalent partial pressure of H 2 and/or D 2 was added. The first-order hydrogen isotope exchange reaction rates were 5.54x10 -2 h -1 for H 2 +T 2 mixed gas and 4.76x10 -2 h -1 for D 2 +T 2 . The actual HT producing rate was nearly equivalent to the rate of DT, but the reverse reaction rate of HT was faster than that of DT. The exchange reaction rates between H, D and T showed the isotope effect, HD>HT>DT. The hydrogen isotope exchange reaction rates observed were about twenty times larger than ion formation rates by beta radiation. This result suggests that a free radical chain reaction in hydrogen isotopes is occurring. (orig.)

  16. Hydrogen isotopic substitution experiments in nanostructured porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, W.D. [Facultad de Ciencias Exactas y Naturales y Agrimensura - (UNNE), Avenida Libertad 5500, 3400 Corrientes (Argentina); Koropecki, R.R. [INTEC (CONICET-UNL), Gueemes 3450, 3000 Santa Fe (Argentina)], E-mail: rkoro@intec.ceride.gov.ar; Arce, R.D. [INTEC (CONICET-UNL), Gueemes 3450, 3000 Santa Fe (Argentina); Busso, A. [Facultad de Ciencias Exactas y Naturales y Agrimensura - (UNNE), Avenida Libertad 5500, 3400 Corrientes (Argentina)

    2008-04-30

    Nanostructured porous silicon is usually prepared by electrochemical anodization of monocrystalline silicon using a fluorine-rich electrolyte. As a result of this process, the silicon atoms conserve their original crystalline location, and many of the dangling bonds appearing on the surface of the nanostructure are saturated by hydrogen coming from the electrolyte. This work presents an IR study of the effects produced by partial substitution of water in the electrolytic solution by deuterium oxide. The isotopic effects on the IR spectra are analyzed for the as-prepared samples and for the samples subjected to partial thermal effusion of hydrogen and deuterium. We demonstrate that, although deuterium is chemically indistinguishable from hydrogen, it presents a singular behaviour when used in porous silicon preparation. We found that deuterium preferentially bonds forming Si-DH groups. A possible explanation of the phenomenon is presented, based on the different diffusivities of hydrogen and deuterium.

  17. Hydrogen isotopic substitution experiments in nanostructured porous silicon

    International Nuclear Information System (INIS)

    Palacios, W.D.; Koropecki, R.R.; Arce, R.D.; Busso, A.

    2008-01-01

    Nanostructured porous silicon is usually prepared by electrochemical anodization of monocrystalline silicon using a fluorine-rich electrolyte. As a result of this process, the silicon atoms conserve their original crystalline location, and many of the dangling bonds appearing on the surface of the nanostructure are saturated by hydrogen coming from the electrolyte. This work presents an IR study of the effects produced by partial substitution of water in the electrolytic solution by deuterium oxide. The isotopic effects on the IR spectra are analyzed for the as-prepared samples and for the samples subjected to partial thermal effusion of hydrogen and deuterium. We demonstrate that, although deuterium is chemically indistinguishable from hydrogen, it presents a singular behaviour when used in porous silicon preparation. We found that deuterium preferentially bonds forming Si-DH groups. A possible explanation of the phenomenon is presented, based on the different diffusivities of hydrogen and deuterium

  18. Method for enriching and separating heavy hydrogen isotopes from substance streams containing such isotopes by means of isotope exchange

    International Nuclear Information System (INIS)

    Knochel, A.; Eggers, I.; Klatte, B.; Wilken, R. D.

    1985-01-01

    A process for enriching and separating heavy hydrogen isotopes having a heavy hydrogen cation (deuterium and/or tritium) from substance streams containing them, wherein the respectively present hydrogen isotopes are exchanged in chemical equilibria. A protic, acid solution containing deuterium and/or tritium is brought into contact with a value material from the group of open-chained polyethers or aminopolyethers, macro-monocyclic or macro-polycyclic polyethers, macro-monocyclic or macro-polycyclic amino polyethers, and mixtures of these values, in their free or proton salt form to form a reaction product of the heavy hydrogen cation with the value or value salt and bring about enrichment of deuterium and/or tritium in the reaction product. The reaction product containing the value or value salt is separated from the solution. The separated reaction product is treated to release the hydrogen isotope(s) to be enriched in the form of deuterium oxide (HDO) and/or tritium oxide (HTO) by regenerating the value or its salt, respectively. The regenerated value is returned for reuse

  19. Separation of tritium from other hydrogen isotopes

    International Nuclear Information System (INIS)

    Roth, E.

    1988-01-01

    The paper describes a plant that has been operated at Marcoule for tritium production and used thermal diffusion enrichment, a facility that was built in Saclay to enrich hydrogen in tritium for low level measurements, and the Laue Langevin Institute tritium extraction plant. Details are given on the project under construction for the tritium separation facility at JET using Gas Chromatography, and on proposals for circuits for NET. Studies on catalysers for liquid phase catalytic exchange, on electrolysers, or different gas chromatography arrangements, are described. Systems designed for reprocessing plants, for detritiation of heavy water by distillation are briefly accounted for

  20. Hydrogen isotope exchange in a metal hydride tube

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, David B. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2014-09-01

    This report describes a model of the displacement of one hydrogen isotope within a metal hydride tube by a different isotope in the gas phase that is blown through the tube. The model incorporates only the most basic parameters to make a clear connection to the theory of open-tube gas chromatography, and to provide a simple description of how the behavior of the system scales with controllable parameters such as gas velocity and tube radius. A single tube can be seen as a building block for more complex architectures that provide higher molar flow rates or other advanced design goals.

  1. Tritium removal by hydrogen isotopic exchange between hydrogen gas and water on hydrophobic catalyst

    International Nuclear Information System (INIS)

    Morishita, T.; Isomura, S.; Izawa, H.; Nakane, R.

    1980-01-01

    Many kinds of the hydrophobic catalysts for hydrogen isotopic exchange between hydrogen gas and water have been prepared. The carriers are the hydrophobic organic materials such as polytetrafluoroethylene(PTFE), monofluorocarbon-PTFE mixture(PTFE-FC), and styrene-divinylbenzene copolymer(SDB). 0.1 to 2 wt % Pt is deposited on the carriers. The Pt/SDB catalyst has much higher activity than the Pt/PTFE catalyst and the Pt/PTFE-FC catalyst shows the intermediate value of catalytic activity. The observation of electron microscope shows that the degrees of dispersion of Pt particles on the hydrophobic carriers result in the difference of catalytic activities. A gas-liquid separated type column containing ten stages is constructed. Each stage is composed of both the hydrophobic catalyst bed for the hydrogen gas/water vapor isotopic exchange and the packed column type bed for the water vapor/liquid water isotopic exchange. In the column hydrogen gas and water flow countercurrently and hydrogen isotopes are separated

  2. Hydrogen isotope storage in zircaloy scrap

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H. S.; Kuk, I. H.; Chung, H.; Paek, S. W.; Kang, H. S

    1999-08-01

    8 MCi of tritium a year will be produced after wolsong TRF is in operation. The metal hydride form is one of useful tritium storage. The metals in use for metal hydride are uranium, titanium, etc., however uranium is limited to use by regulation, and titanium is relatively costly. Both metals are not produced in country but whole amount is imported. On the other hand 2,000kg of zircaloy scrap is produced by CANDU nuclear fuel fabrication process, which is also useful for hydrogen storage. The purpose of this study is to evaluation of hydrogen absorption capacity for zircaloy scrap that is produced as waste by CANDU nuclear fuel fabrication process. The sample evacuated for an hour at 1000 deg C. The strip showed higher capacity : 0.7 at 25 deg C, 2.0 at 200 deg C, 2.0 at 200 deg C, 2.0 at 400 deg C, respectively. The H/M values for commercial zircaloy sponge were 2.0 at 25 deg C and 2.0 at 400 deg C.

  3. Kinetics of hydrogen isotope exchange reactions

    International Nuclear Information System (INIS)

    Gold, V.; McAdam, M.E.

    1975-01-01

    Under the influence of tritium β-radiation, 1,4-dioxan undergoes hydrogen exchange with the solvent water. The inhibition of the reaction by known electron scavengers (Ag + , Cu 2+ , Ni 2+ , Co 2+ , Zn 2+ , H 3 + O) and also by species with high reactivity towards hydroxyl radicals but negligible reactivity towards solvated electrons (N 3 - , Br - , SCN - ) has been examined in detail. γ-irradiation similarly induces hydrogen exchange. The action of scavengers is interpreted as requiring the involvement of two separately scavengeable primary radiolysis products in the sequence of reactions leading to exchange. The presence of electron scavengers, even at high concentration, does not totally inhibit the exchange, and a secondary exchange route, involving a low vacancy state of inhibitor cations, is considered responsible for the 'unscavengeable' portion of the reaction, by providing an alternative exchange route. Analogies are drawn between the exchange reaction and other radiation-induced reactions that are thought to involve spur processes. Some implication of radiation-chemical studies in water-alcohol mixtures are indicated. (author)

  4. Hydrogen isotope storage in zircaloy scrap

    International Nuclear Information System (INIS)

    Lee, H. S.; Kuk, I. H.; Chung, H.; Paek, S. W.; Kang, H. S.

    1999-08-01

    8 MCi of tritium a year will be produced after wolsong TRF is in operation. The metal hydride form is one of useful tritium storage. The metals in use for metal hydride are uranium, titanium, etc., however uranium is limited to use by regulation, and titanium is relatively costly. Both metals are not produced in country but whole amount is imported. On the other hand 2,000kg of zircaloy scrap is produced by CANDU nuclear fuel fabrication process, which is also useful for hydrogen storage. The purpose of this study is to evaluation of hydrogen absorption capacity for zircaloy scrap that is produced as waste by CANDU nuclear fuel fabrication process. The sample evacuated for an hour at 1000 deg C. The strip showed higher capacity : 0.7 at 25 deg C, 2.0 at 200 deg C, 2.0 at 200 deg C, 2.0 at 400 deg C, respectively. The H/M values for commercial zircaloy sponge were 2.0 at 25 deg C and 2.0 at 400 deg C

  5. A revision in hydrogen isotopic composition of USGS42 and USGS43 human-hair stable isotopic reference materials for forensic science

    Science.gov (United States)

    Coplen, Tyler B.; Qi, Haiping

    2016-01-01

    The hydrogen isotopic composition (δ2HVSMOW-SLAP) of USGS42 and USGS43 human hair stable isotopic reference materials, normalized to the VSMOW (Vienna-Standard Mean Ocean Water)–SLAP (Standard Light Antarctic Precipitation) scale, was originally determined with a high temperature conversion technique using an elemental analyzer (TC/EA) with a glassy carbon tube and glassy carbon filling and analysis by isotope-ratio mass spectrometer (IRMS). However, the TC/EA IRMS method can produce inaccurate δ2HVSMOW-SLAPresults when analyzing nitrogen-bearing organic substances owing to the formation of hydrogen cyanide (HCN), leading to non-quantitative conversion of a sample into molecular hydrogen (H2) for IRMS analysis. A single-oven, chromium-filled, elemental analyzer (Cr-EA) coupled to an IRMS substantially improves the measurement quality and reliability of hydrogen isotopic analysis of hydrogen- and nitrogen-bearing organic material because hot chromium scavenges all reactive elements except hydrogen. USGS42 and USGS43 human hair isotopic reference materials have been analyzed with the Cr-EA IRMS method, and the δ2HVSMOW-SLAP values of their non-exchangeable hydrogen fractions have been revised:where mUr = 0.001 = ‰. On average, these revised δ2HVSMOW-SLAP values are 5.7 mUr more positive than those previously measured. It is critical that readers pay attention to the δ2HVSMOW-SLAP of isotopic reference materials in publications as they may need to adjust the δ2HVSMOW–SLAP measurement results of human hair in previous publications to ensure all results are on the same isotope-delta scale.

  6. The potential of Isotope Ratio Mass Spectrometry (IRMS) and gas chromatography-IRMS analysis of triacetone triperoxide in forensic explosives investigations

    NARCIS (Netherlands)

    Bezemer, K.D.B.; Koeberg, M.; Heijden, A.E.D.M. van der; Driel, C.A. va; Blaga, C.; Bruinsma, J.; Asten, A.C. van

    2016-01-01

    Studying links between triacetone triperoxide (TATP) samples from crime scenes and suspects can assist in criminal investigations. Isotope ratio mass spectrometry (IRMS) and gas chromatography (GC)-IRMS were used to measure the isotopic compositions of TATP and its precursors acetone and hydrogen

  7. Solubility of hydrogen isotopes in liquid LiPb

    International Nuclear Information System (INIS)

    Konishi, S.; Yamamoto, Y.; Noborio, K.; Calderoni, P.; Merrill, B.

    2014-01-01

    This research was performed mainly in the first half of the task 1-2 of TITAN project to investigate the interaction between hydrogen isotopes and liquid LiPb. Solubility of hydrogen in liquid LiPb was measured under a static condition. Kyoto University provided the first experimental apparatus shipped to Idaho, and Kyushu University succeeded the experiment and further improved. Obtained solubility generally agreed with some previous reports, but varied orders of magnitudes suggesting influence of impurity or other chemical processes. (author)

  8. Hafnium isotope ratios of nine GSJ reference samples

    International Nuclear Information System (INIS)

    Hanyu, Takeshi; Nakai, Shun'ichi; Tatsuta, Riichiro

    2005-01-01

    176 Hf/ 177 Hf ratios of nine geochemical reference rocks from the Geological Survey of Japan, together with BIR-1 and BCR-2, were determined using multi-collector inductively coupled plasma mass spectrometry. Our data for BIR-1, BCR-2 and JB-1 are in agreement with those previously reported, demonstrating the appropriateness of the chemical procedure and isotopic measurement employed in this study. The reference rocks have a wide range of 176 Hf/ 177 Hf covering the field defined by various volcanic rocks, such as mid-ocean ridge basalts, ocean island basalts, and subduction related volcanic rocks. They are therefore suitable as rock standards for Hf isotope measurement of geological samples. (author)

  9. Determination of hydrogen/deuterium ratio with neutron measurements on MAST

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, I., E-mail: iwona.klimek@physics.uu.se; Cecconello, M.; Ericsson, G. [Department of Physics and Astronomy, Uppsala University, Uppsala (Sweden); Sharapov, S. E.; Harrison, J. [CCFE, Culham Science Centre, Abingdon (United Kingdom)

    2014-11-15

    On MAST, compressional Alfvén eigenmodes can be destabilized by the presence of a sufficiently large population of energetic particles in the plasma. This dependence was studied in a series of very similar discharges in which increasing amounts of hydrogen were puffed into a deuterium plasma. A simple method to estimate the isotopic ratio n{sub H}/n{sub D} using neutron emission measurements is here described. The inferred isotopic ratio ranged from 0.0 to 0.6 and no experimental indication of changes in radial profile of n{sub H}/n{sub D} were observed. These findings are confirmed by TRANSP/NUBEAM simulations of the neutron emission.

  10. Deuterium isotope separation factor between hydrogen and liquid water

    International Nuclear Information System (INIS)

    Rolston, J.H.; den Hartog, J.; Butler, J.P.

    1976-01-01

    The overall deuterium isotope separation factor between hydrogen and liquid water, α, has been measured directly for the first time between 280 and 370 0 K. The data are in good agreement with values of α calculated from literature data on the equilibrium constant for isotopic exchange between hydrogen and water vapor, K 1 , and the liquid-vapor separation factor, α/sub V/. The temperature dependence of α over the range 273-473 0 K based upon these new experimental results and existing literature data is given by the equation ln α = -0.2143 + (368.9/T) + (27,870/T 2 ). Measurements on α/sub V/ given in the literature have been surveyed and the results are summarized over the same temperature range by the equation ln α/sub V/ = 0.0592 - (80.3/T) +

  11. Hydrogen isotopes transport parameters in fusion reactor materials

    International Nuclear Information System (INIS)

    Serra, E.; Ogorodnikova, O.V.

    1998-01-01

    This work presents a review of hydrogen isotopes-materials interactions in various materials of interest for fusion reactors. The relevant parameters cover mainly diffusivity, solubility, trap concentration and energy difference between trap and solution sites. The list of materials includes the martensitic steels (MANET, Batman and F82H-mod.), beryllium, aluminium, beryllium oxide, aluminium oxide, copper, tungsten and molybdenum. Some experimental work on the parameters that describe the surface effects is also mentioned. (orig.)

  12. Experimental study of hydrogen isotopes storage on titanium bed

    International Nuclear Information System (INIS)

    Vasut, Felicia; Zamfirache, Marius; Bornea, Anisia; Pearsica, Claudia; Bidica, Nicolae

    2002-01-01

    As known, the Nuclear Power Plant Cernavoda equipped with a Canadian reactor, of CANDU type, is the most powerful tritium source from Europe. On long term, due to a 6·10 16 Bq/year, Cernavoda area will be contaminated due to the increasing tritium quantity. Also, the continuous contamination of heavy water from the reactor, induces a reduction of moderation's capacity. Therefore, one considers that it is improperly to use heavy water if its activity level is higher than 40 Ci/kg in the moderator and 2 Ci/kg in the cooling fluid. For these reasons, we have developed a detritiation technology, based on catalytic isotopic exchange and cryogenic distillation. Tritium will be removed from the tritiated heavy water, so it appears the necessity of storage of tritium in a special vessel that can provide a high level of protection and safety of environment and personal. There several metals were tested as storage beds for hydrogen isotopes. One of the reference materials used for storage of hydrogen isotopes is uranium, a material with a great storage capacity, but unfortunately it is a radioactive metal and also can react with the impurities from the stored gas. Other metals and alloys as ZrCo, Ti, FeTi are also adequate as storage beds at normal temperature. The paper presents studies about the reaction between hydrogen and titanium used as storage bed for the hydrogen isotopes resulted after the detritiation of tritiated heavy water. The experiments that were carried out used protium and mixture of deuterium and protium at different storage parameters as process gas. (authors)

  13. Separation of hydrogen isotopes for tritium waste removal

    International Nuclear Information System (INIS)

    Wilkes, W.R.

    1975-01-01

    A distillation cascade for separating hydrogen isotopes was simulated by means of a multicomponent, multistage computer code. A hypothetical test mixture containing equal atomic fractions of protium, deuterium and tritium, equilibrated to high temperature molecular concentrations was used as feed. The results show that a two-column cascade can be used to separate the protium from the tritium. Deuterium appears both in the protium and the tritium product streams. (auth)

  14. Carbon isotope ratios and isotopic correlations between components in fruit juices

    Science.gov (United States)

    Wierzchnicki, Ryszard

    2013-04-01

    Nowadays food products are defined by geographical origin, method of production and by some regulations concerning terms of their authenticity. Important data for confirm the authenticity of product are providing by isotopic methods of food control. The method checks crucial criteria which characterize the authenticity of inspected product. The European Union Regulations clearly show the tendency for application of the isotopic methods for food authenticity control (wine, honey, juice). The aim of the legislation steps is the protection of European market from possibility of the commercial frauds. Method of isotope ratio mass spectrometry is very effective tool for the use distinguishably the food products of various geographical origin. The basic problem for identification of the sample origin is the lack of databases of isotopic composition of components and information about the correlations of the data. The subject of the work was study the isotopic correlations existing between components of fruits. The chemical and instrumental methods of separation: water, sugars, organic acids and pulp from fruit were implemented. IRMS technique was used to measure isotopic composition of samples. The final results for original samples of fruits (apple, strawberry etc.) will be presented and discussed. Acknowledgement: This work was supported by the Polish Ministry of Science and Higher Education under grant NR12-0043-10/2010.

  15. Stable strontium isotopic ratios from archaeological organic remains from the Thorsberg peat bog

    DEFF Research Database (Denmark)

    Nosch, Marie-Louise Bech; von Carnap-Bornheim, Claus; Grupe, Gisela

    2007-01-01

    Pilot study analysing stable strontium isotopic ratios from Iron Age textile and leather finds from the Thorsberg peat bog.......Pilot study analysing stable strontium isotopic ratios from Iron Age textile and leather finds from the Thorsberg peat bog....

  16. Low temperature isotope effects of hydrogen diffusion in metallic glasses

    International Nuclear Information System (INIS)

    Hofmann, A.; Kronmueller, H.

    1989-01-01

    Snoek-like relaxation peaks of Hydrogen and Deuterium in amorphous Fe 80 B 20 , Fe 40 Ni 40 P 14 B 6 and Fe 91 Zr 9 are detected. At low H, D concentrations the peaks are near 200 K and show small isotope effects of the average activation energies (anti Q H ≅ 0.6 eV, anti Q D - anti Q H ≤ 10 meV). For higher H, D-contents the peaks shift to lower temperatures around to 120 K and show distinct isotope effects in the activation energies (anti Q H ≅ 0.3 eV, anti Q D - anti Q H ≅ 30 meV) and in the amplitude of the low temperature tails of the relaxation peaks. This points to isotope mass dependent deviations from the Arrhenius law due to nonthermal tunneling processes. (orig.)

  17. Stable hydrogen, oxygen and sulfur isotopes composition in different tissues of cattle

    International Nuclear Information System (INIS)

    Sun Fengmei; Shi Guangyu; Wang Huiwen; Yang Shuming

    2012-01-01

    In order to research on stable hydrogen, oxygen, sulfur isotopes composition in different tissues of cattle, as well as the breed, δ 2 H and δ 34 S values of different defatted muscle, cattle tail hair, blood, liver, also δ 2h and δ 18 O values of water from muscle were determined by isotope ratio mass spectrometry. The stable sulfur isotope composition was not affected by cattle variety, meanwhile the hydrogen was uncertain; the δ 2 H and δ 34 S values between different defatted muscle, blood, liver, cattle hair were significantly different, at the same time the δ 34 S and δ 2 H values between each tissue were not significantly correlated; the δ 2 H values were strongly correlated with the δ 18 O values of muscle water. The above results indicated that stable sulfur and hydrogen isotopes fractionation in the various tissues were discrepant, thus the proper tissue should be selected according to the purpose and object in the beef traceability. (authors)

  18. Carbon and hydrogen isotope fractionation under continuous light: implications for paleoenvironmental interpretations of the High Arctic during Paleogene warming.

    Science.gov (United States)

    Yang, Hong; Pagani, Mark; Briggs, Derek E G; Equiza, M A; Jagels, Richard; Leng, Qin; Lepage, Ben A

    2009-06-01

    The effect of low intensity continuous light, e.g., in the High Arctic summer, on plant carbon and hydrogen isotope fractionations is unknown. We conducted greenhouse experiments to test the impact of light quantity and duration on both carbon and hydrogen isotope compositions of three deciduous conifers whose fossil counterparts were components of Paleogene Arctic floras: Metasequoia glyptostroboides, Taxodium distichum, and Larix laricina. We found that plant leaf bulk carbon isotopic values of the examined species were 1.75-4.63 per thousand more negative under continuous light (CL) than under diurnal light (DL). Hydrogen isotope values of leaf n-alkanes under continuous light conditions revealed a D-enriched hydrogen isotope composition of up to 40 per thousand higher than in diurnal light conditions. The isotope offsets between the two light regimes is explained by a higher ratio of intercellular to atmospheric CO(2) concentration (C (i)/C (a)) and more water loss for plants under continuous light conditions during a 24-h transpiration cycle. Apparent hydrogen isotope fractionations between source water and individual lipids (epsilon(lipid-water)) range from -62 per thousand (Metasequoia C(27) and C(29)) to -87 per thousand (Larix C(29)) in leaves under continuous light. We applied these hydrogen fractionation factors to hydrogen isotope compositions of in situ n-alkanes from well-preserved Paleogene deciduous conifer fossils from the Arctic region to estimate the deltaD value in ancient precipitation. Precipitation in the summer growing season yielded a deltaD of -186 per thousand for late Paleocene, -157 per thousand for early middle Eocene, and -182 per thousand for late middle Eocene. We propose that high-latitude summer precipitation in this region was supplemented by moisture derived from regionally recycled transpiration of the polar forests that grew during the Paleogene warming.

  19. Scales of guide field reconnection at the hydrogen mass ratio

    International Nuclear Information System (INIS)

    Lapenta, G.; Markidis, S.; Divin, A.; Goldman, M.; Newman, D.

    2010-01-01

    We analyze the signatures of component reconnection for a Harris current sheet with a guide field using the physical mass ratio of hydrogen. The study uses the fully kinetic particle in cell code IPIC3D to investigate the scaling with mass ratio of the following three main component reconnection features: electron density cavities along the separatrices, channels of fast electron flow within the cavities, and electron phase space holes due to the Buneman instability in the electron high speed channels. The width and strength of the electron holes and of the electron cavities are studied up the mass ratio proper of hydrogen, considering the effect of the simulation box size, and of the boundary conditions. The results compare favorably with the existing data from the Cluster and Themis missions and provide quantitative predictions for realistic conditions to be encountered by the planned magnetospheric multiscale mission.

  20. The measurement of the isotope ratios and concentrations of zinc by thermal ionization mass spectrometry using double isotope dilution

    International Nuclear Information System (INIS)

    Deng Zhongguo

    1994-01-01

    The isotope ratios and concentrations of zinc are measured by silicagel-thermal ionization mass spectrometry using the double isotope spikers. The double isotope spikers ( 70 Zn and 67 Zn-enriched isotopes) are used to correct the isotope mass fractionation for the zinc isotope ratios, and to certify the zinc concentrations in the unknown samples. The zinc concentrations of these double isotope spikers are surveyed by a spiker made of pure (99.99%) natural zinc metal powder. The correcting factors (f a , f t and f n ) of the zinc isotope ratios in the spiked mixture, spike and unspiked samples for the isotope mass fractionation, and the spike-to-unspiked ratios (X r ) of the zinc isotope r in the spiked mixture samples can be obtained to solve the matrix equations by numerical approximation. The natural zinc isotope ratios are: 64 Zn/ 67 Zn = 11.8498, 66 Zn/ 67 Zn = 6.7977, 68 Zn/ 67 Zn = 4.5730 and 70 Zn/ 67 Zn = 0.1520. The uncertainties determined of the isotope ratios and concentrations of zinc are +- 0.16% and +-0.31%, respectively

  1. Atlas cross section for scattering of muonic hydrogen atoms on hydrogen isotope molecules

    International Nuclear Information System (INIS)

    Adamczak, A.; Faifman, M.P.; Ponomarev, L.I.

    1996-01-01

    The total cross sections of the elastic, spin-flip, and charge-exchange processes for the scattering of muonic hydrogen isotope atoms (pμ, dμ, tμ) in the ground state on the hydrogen isotope molecules (H 2 , D 2 , T 2 , HD, HT, DT) are calculated. The scattering cross sections of muonic hydrogen isotope atoms on hydrogen isotope nuclei obtained earlier in the multichannel adiabatic approach are used in the calculations. Molecular effects (electron screening, rotational and vibrational excitations of target molecules, etc.) are taken into account. The spin effects of the target molecules and of the incident muonic atoms are included. the cross sections are averaged over the Boltzmann distribution of the molecule rotational states and the Maxwellian distribution of the target molecule kinetic energies for temperatures 30, 100, 300, and 1000 K. The cross sections are given for kinetic energies of the incident muonic atoms ranging from 0.001 to 100 eV in the laboratory frame. 45 refs., 6 tabs

  2. A lead isotope ratio data base of ancient Chinese bronzes

    International Nuclear Information System (INIS)

    Jin Zhengyao

    2005-01-01

    A data base of lead isotope ratio of ancient Chinese bronzes is set up. There are 2888 members, including bronze objects, casting remains, and related ores, etc. in the file. The file contents of data base are made from analysis work on Chinese bronze previously carried out in several laboratories in China, Japan and USA. The main body of the file contents is formed from records, analysis data, reference documents, and images. The data base is designed for sharing information in provenance study on raw metal material for bronze production in China Bronze Age. (author)

  3. Membrane pumping technology, helium and hydrogen isotopes separation in the fusion hydrogen

    International Nuclear Information System (INIS)

    Pigarov, A.Yu.; Pistunovich, V.I.; Busnyuk, A.O.

    1994-01-01

    A gas pumping system for the ITER, improved by implementation of superpermeable membranes for selective hydrogen isotope exhaust, is considered. The study of the pumping capability of a niobium membrane for a hydrogen-helium mixture has been fulfilled. The membrane superpermeability can be only realized for atomic hydrogen. Helium does not pass through the membrane, and its presence does not affect the hydrogen pumping. A detailed Monte Carlo simulation of gas behavior for the experimental facility has been done. The probability of permeation for a hydrogen atom for one collision with the membrane is ∼0.1; the same probability of molecule permeation is ∼10 -5 . The probability for atomization, i.e. re-emission of an atomizer is ∼0.2; the probability of recombination of an atom is ∼0.2

  4. Thermal desorption spectroscopy for investigating hydrogen isotope behavior in materials

    International Nuclear Information System (INIS)

    Xia Tirui; Yang Hongguang; Zhan Qin; Han Zhibo; He Changshui

    2012-01-01

    The behavior of hydrogen isotope generated in fusion reactor materials is the key issue for safety and economic operation of fusion reactors and becomes an interesting field. In order to investigate the mechanism of hydrogen isotope such as diffusion, release and retention, a high-sensitivity thermal desorption spectroscopy (TDS) in combination with a quadruple mass spectrometer (QMS) was developed. A major technical breakthrough in ultrahigh vacuum (UHV), low hydrogen background, linear heating and sensitivity calibration of TDS system was made. UHV of l × 10 -7 Pa and low hydrogen background of l × 10 -9 Pa were obtained by combining turbo molecule pump and sputter ion pump. Specimens can be linearly heated up to 1173 K at the rate of 1 to 50 K/min under the MCGS PID software. Sensitivity calibration of the TDS system was accomplished using a special deuterium leak in the detector mode of QMS second electron multiplier. The desorption sensitivity coefficient and the minimum detection limit of deuterium desorption rate are 6.22 × l0 24 s -l · and l.24 × l0 -10 s -1 , respectively. The measurement was also routinely conducted on a specimen of standard, deuterium-containing Zr-4 alloy maintained in the laboratory, so as to validate the TDS method. (authors)

  5. Diamond and Diamond-Like Materials as Hydrogen Isotope Barriers

    International Nuclear Information System (INIS)

    Foreman, L.R.; Barbero, R.S.; Carroll, D.W.; Archuleta, T.; Baker, J.; Devlin, D.; Duke, J.; Loemier, D.; Trukla, M.

    1999-01-01

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The purpose of this project was to develop diamond and diamond-like thin-films as hydrogen isotope permeation barriers. Hydrogen embrittlement limits the life of boost systems which otherwise might be increased to 25 years with a successful non-reactive barrier. Applications in tritium processing such as bottle filling processes, tritium recovery processes, and target filling processes could benefit from an effective barrier. Diamond-like films used for low permeability shells for ICF and HEDP targets were also investigated. Unacceptable high permeabilities for hydrogen were obtained for plasma-CVD diamond-like-carbon films

  6. What climate information is recorded in stable isotope ratios of wood lignin methoxyl groups?

    Science.gov (United States)

    Greule, Markus; Keppler, Frank

    2010-05-01

    The stable isotope composition of the bioelements C, O, H and N in plant organic matter is known to be a very powerful for various environmental impacts. Particularly tree rings are suitable for this analysis because they exhibit a "climate archive" with a yearly or even biannual resolution. One of the most determined wood compounds is cellulose which amongst others is used to reconstruct the temperature due to measurement of stable hydrogen and oxygen isotopes. Therefore cellulose is converted into cellulose nitrate to eliminate the exchangeable hydroxyl hydrogen or equilibration methods are used. However, a general problem associated with the determination of the stable hydrogen values of marker compounds for the study of climate and environmental conditions is the isolation of the pure compound for analysis by isotope ratio mass spectrometry. Exploitation of components of wood as markers, in particular, has been restricted by the very labour intensive and time consuming preparation of samples (e.g. cellulose nitrate). An alternative way to record climate information from tree rings was recently proposed by Keppler et al. (2007) who measured the stable hydrogen values of methoxyl groups in wood. Lignin methoxyl groups are considered to be stable, i.e. the hydrogen atoms of the methoxyl moiety do not exchange with those of plant water during ongoing metabolic reactions in the plant. Thus the initial deuterium content of the methoxyl groups of lignin in woody tissue at formation is retained throughout the lifetime of the tree and in preserved tissue. The methoxyl content of lignin in wood is usually determined by the Zeisel method (Zeisel, 1885) - the reaction between methyl ethers and hydroiodic acid to form methyl iodide. Exploiting this reaction for the measurement of stable hydrogen values of lignin methoxyl groups ensures that during the entire analytical procedure the isotope signal is preserved since no isotopic exchange occurs between the methyl groups and

  7. Determination of uranium and its isotopic ratios in environmental samples

    International Nuclear Information System (INIS)

    Flues Szeles, M.S.M.

    1990-01-01

    A method for the determination of uranium and its isotopic ratios ( sup(235)U/ sup(238)U and sup(234U/ sup(238)U) is established in the present work. The method can be applied in environmental monitoring programs of uranium enrichment facilities. The proposed method is based on the alpha spectrometry technique which is applied after a purification of the sample by using an ionic exchange resin. The total yield achieved was (91 + 5)% with a precision of 5%, an accuracy of 8% and a lower limit of detection of 7,9 x 10 sup(-4)Bq. The uranium determination in samples containing high concentration of iron, which is an interfering element present in environmental samples, particularly in soil and sediment, was also studied. The results obtained by using artificial samples containing iron and uranium in the ratio 1000:1, were considered satisfactory. (author)

  8. Field Sample Preparation Method Development for Isotope Ratio Mass Spectrometry

    International Nuclear Information System (INIS)

    Leibman, C.; Weisbrod, K.; Yoshida, T.

    2015-01-01

    Non-proliferation and International Security (NA-241) established a working group of researchers from Los Alamos National Laboratory (LANL), Pacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory (SRNL) to evaluate the utilization of in-field mass spectrometry for safeguards applications. The survey of commercial off-the-shelf (COTS) mass spectrometers (MS) revealed no instrumentation existed capable of meeting all the potential safeguards requirements for performance, portability, and ease of use. Additionally, fieldable instruments are unlikely to meet the International Target Values (ITVs) for accuracy and precision for isotope ratio measurements achieved with laboratory methods. The major gaps identified for in-field actinide isotope ratio analysis were in the areas of: 1. sample preparation and/or sample introduction, 2. size reduction of mass analyzers and ionization sources, 3. system automation, and 4. decreased system cost. Development work in 2 through 4, numerated above continues, in the private and public sector. LANL is focusing on developing sample preparation/sample introduction methods for use with the different sample types anticipated for safeguard applications. Addressing sample handling and sample preparation methods for MS analysis will enable use of new MS instrumentation as it becomes commercially available. As one example, we have developed a rapid, sample preparation method for dissolution of uranium and plutonium oxides using ammonium bifluoride (ABF). ABF is a significantly safer and faster alternative to digestion with boiling combinations of highly concentrated mineral acids. Actinides digested with ABF yield fluorides, which can then be analyzed directly or chemically converted and separated using established column chromatography techniques as needed prior to isotope analysis. The reagent volumes and the sample processing steps associated with ABF sample digestion lend themselves to automation and field

  9. Measurement system analysis (MSA) of the isotopic ratio for uranium isotope enrichment process control

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Josue C. de; Barbosa, Rodrigo A.; Carnaval, Joao Paulo R., E-mail: josue@inb.gov.br, E-mail: rodrigobarbosa@inb.gov.br, E-mail: joaocarnaval@inb.gov.br [Industrias Nucleares do Brasil (INB), Rezende, RJ (Brazil)

    2013-07-01

    Currently, one of the stages in nuclear fuel cycle development is the process of uranium isotope enrichment, which will provide the amount of low enriched uranium for the nuclear fuel production to supply 100% Angra 1 and 20% Angra 2 demands. Determination of isotopic ration n({sup 235}U)/n({sup 238}U) in uranium hexafluoride (UF{sub 6} - used as process gas) is essential in order to control of enrichment process of isotopic separation by gaseous centrifugation cascades. The uranium hexafluoride process is performed by gas continuous feeding in separation unit which uses the centrifuge force principle, establishing a density gradient in a gas containing components of different molecular weights. The elemental separation effect occurs in a single ultracentrifuge that results in a partial separation of the feed in two fractions: an enriched on (product) and another depleted (waste) in the desired isotope ({sup 235}UF{sub 6}). Industrias Nucleares do Brasil (INB) has used quadrupole mass spectrometry (QMS) by electron impact (EI) to perform isotopic ratio n({sup 235}U)/n({sup 238}U) analysis in the process. The decision of adjustments and change te input variables are based on the results presented in these analysis. A study of stability, bias and linearity determination has been performed in order to evaluate the applied method, variations and systematic errors in the measurement system. The software used to analyze the techniques above was the Minitab 15. (author)

  10. Sulfur isotope in nature. Determination of sulfur isotope ratios in coal and petroleum by mass spectrometry

    International Nuclear Information System (INIS)

    Derda, M.

    1999-01-01

    Elementary sulfur or in chemical compounds is one of the elements widespread in the earth's crust and biosphere. Its participation in earth's crust amounts to 0.26 % by weight. Measurement of isotope composition of natural samples can deliver many information about origin, creation and transformation ranges of rocks and minerals. Sulfur isotope ratio contained in minerals is variable and for this reason investigation of isotope sulfur composition can deliver useful information about the geochemistry of each component. Therefore in the investigated sample it is necessary to determine not only the content of sulfur but also the isotope composition of each component. Differentiation of contents of sulfur-34 in natural sulfur compounds can reach up to 110 per mile. So large divergences can be explained by a kinetic effect or by bacterial reduction of sulphates. In this report a wide review of the results of investigations of isotope sulfur compositions in coal and petroleum are presented as well as the methods for the preparation of samples for mass spectrometry analysis are proposed. (author)

  11. Extreme changes in stable hydrogen isotopes and precipitation characteristics in a landfalling Pacific storm

    Science.gov (United States)

    Coplen, T.B.; Neiman, P.J.; White, A.B.; Landwehr, J.M.; Ralph, F.M.; Dettinger, M.D.

    2008-01-01

    With a new automated precipitation collector we measured a remarkable decrease of 51??? in the hydrogen isotope ratio (?? 2H) of precipitation over a 60-minute period during the landfall of an extratropical cyclone along the California coast on 21 March 2005. The rapid drop in ??2H occurred as precipitation generation transitioned from a shallow to a much deeper cloud layer, in accord with synoptic-scale ascent and deep "seeder-feeder" precipitation. Such unexpected ?? 2H variations can substantially impact widely used isotope-hydrograph methods. From extreme ??2H values of -26 and -78???, we calculate precipitation temperatures of 9.7 and -4.2??C using an adiabatic condensation isotope model, in good agreement with temperatures estimated from surface observations and radar data. This model indicates that 60 percent of the moisture was precipitated during ascent as temperature decreased from 15??C at the ocean surface to -4??C above the measurement site.

  12. Examining Changes in Radioxenon Isotope Activity Ratios during Subsurface Transport

    Science.gov (United States)

    Annewandter, R.

    2013-12-01

    The Non-Proliferation Experiment (NPE) has demonstrated and modelled the usefulness of barometric pumping induced soil gas sampling during On-Site inspections. Gas transport has been widely studied with different numerical codes. However, gas transport of all radioxenons in the post-detonation regime and their possible fractionation is still neglected in the open literature. Atmospheric concentrations of the radioxenons Xe-135, Xe-133m, Xe-133 and Xe-131m can be used to discriminate between civilian releases (nuclear power plants or medical isotope facilities), and nuclear explosion sources. It is based on the isotopic activity ratio method. Yet it is not clear whether subsurface migration of the radioxenons, with eventual release into the atmosphere, can affect the activity ratios due to fractionation. Fractionation can be caused by different diffusivities due to mass differences between the radioxenons. A previous study showed surface arrival time of a chemically inert gaseous tracer is affected by its diffusivity. They observed detectable amount for SF6 50 days after detonation and 375 days for He-3. They predict 50 and 80 days for Xe-133 and Ar-37 respectively. Cyclical changes in atmospheric pressure can drive subsurface gas transport. This barometric pumping phenomenon causes an oscillatoric flow in upward trending fractures which, combined with diffusion into the porous matrix, leads to a net transport of gaseous components - a ratcheting effect. We use a general purpose reservoir simulator (Complex System Modelling Platform, CSMP++) which has been applied in a range of fields such as deep geothermal systems, three-phase black oil simulations , fracture propagation in fractured, porous media, Navier-Stokes pore-scale modelling among others. It is specifically designed to account for structurally complex geologic situation of fractured, porous media. Parabolic differential equations are solved by a continuous Galerkin finite-element method, hyperbolic

  13. Process for hydrogen isotope exchange and concentration between liquid water and hydrogen gas and catalyst assembly therefor

    International Nuclear Information System (INIS)

    Stevens, W.H.

    1975-01-01

    A bithermal, catalytic, hydrogen isotope exchange process between liquid water and hydrogen gas to effect concentration of the deuterium isotope of hydrogen is described. Liquid water and hydrogen gas are contacted with one another and with at least one catalytically active metal selected from Group VIII of the Periodic Table; the catalyst body has a water repellent, gas and water vapor permeable, organic polymer or resin coating, preferably a fluorinated olefin polymer or silicone resin coating, so that the isotope exchange takes place by two simultaneously occurring, and closely coupled in space, steps and concentration is effected by operating two interconnected sections containing catalyst at different temperatures. (U.S.)

  14. ICP-MS with hexapole collision cell for isotope ratio measurements of Ca, Fe, and Se.

    Science.gov (United States)

    Boulyga, S F; Becker, J S

    2001-07-01

    To avoid mass interferences on analyte ions caused by argon ions and argon molecular ions via reactions with collision gases, an rf hexapole filled with helium and hydrogen has been used in inductively coupled plasma mass spectrometry (ICP-MS), and its performance has been studied. Up to tenfold improvement in sensitivity was observed for heavy elements (m > 100 u), because of better ion transmission through the hexapole ion guide. A reduction of argon ions Ar+ and the molecular ions of argon ArX+ (X = O, Ar) by up to three orders of magnitude was achieved in a hexapole collision cell of an ICP-MS ("Platform ICP", Micromass, Manchester, UK) as a result of gas-phase reactions with hydrogen when the hexapole bias (HB) was set to 0 V; at an HB of 1.6 V argon, and argon-based ions of masses 40 u, 56 u, and 80 u, were reduced by approximately four, two, and five orders of magnitude, respectively. The signal-to-noise ratio 80Se/ 40Ar2+ was improved by more than five orders of magnitude under optimized experimental conditions. Dependence of mass discrimination on collision-cell properties was studied in the mass range 10 u (boron) to 238 u (uranium). Isotopic analysis of the elements affected by mass-spectrometric interference, Ca, Fe, and Se, was performed using a Meinhard nebulizer and an ultrasonic nebulizer (USN). The measured isotope ratios were comparable with tabulated values from IUPAC. Precision of 0.26%, 0.19%, and 0.12%, respectively, and accuracy of 0.13% 0.25%, and 0.92%, respectively, was achieved for isotope ratios 44Ca/ 40Ca and 56Fe/57Fe in 10 microg L(-1) solution nebulized by means of a USN and for 78Se/80Se in 100 microg L(-1) solution nebulized by means of a Meinhard nebulizer.

  15. Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Kuehnel, Matthias

    2014-02-15

    This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

  16. Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

    International Nuclear Information System (INIS)

    Kuehnel, Matthias

    2014-02-01

    This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

  17. Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Kuehnel, Matthias

    2014-02-15

    This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

  18. Variation in catchment areas of Indiana bat (Myotis sodalis) hibernacula inferred from stable hydrogen (δ2H) isotope analysis.

    Science.gov (United States)

    E.R. Britzke; S.C. Loeb; C.S. Romanek; K.A. Hobson; M.J. Vonhof

    2013-01-01

    Understanding seasonal movements of bats is important for effective conservation efforts. Although female Indiana bats (Myotis sodalis Miller and Allen, 1928) have been documented to migrate >500 km, knowledge of their migratory patterns is still extremely limited. We used the relationship between latitude and stable hydrogen isotope ratio in bat hair (δ...

  19. Multi-saline sample distillation apparatus for hydrogen isotope analyses: design and accuracy. Water-resources investigations

    International Nuclear Information System (INIS)

    Hassan, A.A.

    1981-04-01

    A distillation apparatus for saline water samples was designed and tested. Six samples may be distilled simultaneously. The temperature was maintained at 400 degrees C to ensure complete dehydration of the precipitating salts. Consequently, the error in the measured ratio of stable hydrogen isotopes resulting from incomplete dehydration of hydrated salts during distillation was eliminated

  20. Stable isotope methods: The effect of gut contents on isotopic ratios of zooplankton

    Science.gov (United States)

    Hill, J. M.; McQuaid, C. D.

    2011-05-01

    In the past decade there has been an increased awareness of the potential for methodological bias resulting from multiple pre-analytical procedures in foodweb interpretations based on stable isotope techniques. In the case of small organisms, this includes the effect of gut contents on whole body signatures. Although gut contents may not reflect actual assimilation, their carbon and nitrogen values will be isotopically lighter than after the same material has been assimilated. The potential skewing of isotopic ratios in whole organism samples is especially important for aquatic environments as many studies involve trophic relationships among small zooplankton. This is particularly important in pelagic waters, where herbivorous zooplankton comprise small taxa. Hence this study investigated the effect of gut contents on the δ13C and δ15N ratios of three size classes of zooplankton (1.0-2.0, 2.0-4.0 and >4.0 mm) collected using bongo net tows in the tropical waters of the south-west Indian Ocean. Animals were collected at night, when they were likely to be feeding, sieved into size classes and separated into genera. We focused on Euphausia spp which dominated zooplankton biomass. Three treatment types were processed: bulk animals, bulk animals without guts and tail muscle from each size class at 10 bongo stations. The δ15N ratios were influenced by zooplankton size class, presumably reflecting ontogenetic changes in diet. ANOVA post hoc results and correlations in δ15N signatures among treatments suggest that gut contents may not affect overall nitrogen signatures of Euphausia spp., but that δ13C signatures may be significantly altered by their presence. Carbon interpretations however, were complicated by potential effects of variation in chitin, lipids and metabolism among tissues and the possibility of opportunistic omnivory. Consequently we advocate gut evacuation before sacrifice in euphausiids if specific tissue dissection is impractical and recommend

  1. Investigation of the feeding effect on the 13C/12C isotope ratio of the hormones in bovine urine using gas chromatography/combustion isotope ratio mass spectrometry

    NARCIS (Netherlands)

    Balizs, Gabor; Jainz, Annett; Horvatovich, Peter

    2005-01-01

    The effect of the feeding on the 13C/12C isotope ratio of four endogenous steroid hormones testosterone (T), epi-testosterone (epi-T), dehydroepiandrosterone (DHEA) and etiocholanolone (ETIO) in bovine urine was investigated. An analytical method to determine the accurate isotope ratio was developed

  2. The Laboratory for Laser Energetics’ Hydrogen Isotope Separation System

    Energy Technology Data Exchange (ETDEWEB)

    Shmayda, W.T., E-mail: wshm@lle.rochester.edu; Wittman, M.D.; Earley, R.F.; Reid, J.L.; Redden, N.P.

    2016-11-01

    The University of Rochester’s Laboratory for Laser Energetics has commissioned a hydrogen Isotope Separation System (ISS). The ISS uses two columns—palladium on kieselguhr and molecular sieve—that act in a complementary manner to separate the hydrogen species by mass. The 4-sL per day throughput system is compact and has no moving parts. The columns and the attendant gas storage and handling subsystems are housed in a 0.8 -m{sup 3} glovebox. The glovebox uses a helium cover gas that is continuously processed to extract oxygen and water vapor that permeates through the glovebox gloves and any tritium that is released while attaching or detaching vessels to add feedstock to or drawing product from the system. The isotopic separation process is automated and does not require manual intervention. A total of 315 TBq of tritium was extracted from 23.6 sL of hydrogen with tritium purities reaching 99.5%. Deuterium was the sole residual component in the processed gas. Raffinate contained 0.2 TBq of activity was captured for reprocessing. The total emission from the system to the environment was 0.4 GBq over three weeks.

  3. Romanian wines characterization with CF-IRMS (Continuous Flow Isotope Ratio Mass Spectrometry) isotopic analysis

    International Nuclear Information System (INIS)

    Costinel, Diana; Ionete, Roxana Elena; Vremera, Raluca; Stanciu, Vasile

    2007-01-01

    Wine growing has been known for centuries long in Romania. The country has been favored by its geographical position in south-eastern Europe, by its proximity to the Black Sea, as well as by the specificity of the local soil and climate. Alongside France, Italy, Spain, Germany, countries in this area like Romania could also be called 'a vine homeland' in Europe. High quality wines produced in this region were object of trade ever since ancient times. Under current EU research projects, it is necessary to develop new methods of evidencing wine adulteration and safety. The use of mass spectrometry (MS) to determine the ratios of stable isotopes in bio-molecules now provides the means to prove the botanical and geographical origin of a wide variety of foodstuffs - and therefore, to authenticate and eliminate fraud. Isotope analysis has been officially adopted by the EU as a means of controlling adulteration of wine. Adulteration of wine can happen in many ways, e.g. addition of non-grape ethanol, addition of non-grape sugar, water or other unauthorized substances, undeclared mixing of wines from different wards, geographical areas or countries, mislabelling of variety and age. The present paper emphasize the isotopic analysis for D/H, 18 O/ 16 O, 13 C/ 12 C from wines, using a new generation Isotope Ratio MS, Finnigan Delta V Plus, coupling with a three flexible continuous flow preparation device (GasBench II, TC Elemental Analyser and GC-C/TC). Therefore authentication of wines is an important problem to which isotopic analysis has made a significant contribution. (authors)

  4. Investigations on the heterogenous catalytic hydrogenation using isotope effect and gamma- and neutron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kudlacek, R; Cabicar, J [Ceske Vysoke Uceni Technicke, Prague (Czechoslovakia). Katedra Jaderne Chemie

    1976-01-01

    The kinetic and solvent isotope effects during the maleic acid heterogeneous catalytic hydrogenation and deuteration in light and heavy water have been studied. Also the effect of the gamma and neutron irradiation on the Ni-ZnO catalysts (with various ratios of components) on the reaction kinetics and mechanism has been measured, as well as the effect of pH on the adsorption behaviour of maleic acid and the temperature dependence of the reaction rate. Existence of different adsorption centers for hydrogen and maleic acid could be deduced from these experiments. A reaction mechanism based on the two-dimensional diffusion of components in the surface is proposed. The catalyst is formed from Ni and ZnO-microspheres. Hydrogen is bound to nickel and maleic acid is adsorbed on the ZnO-microspheres. The reaction takes place on the boundary layers of these microspheres.

  5. Mixed-mode chromatography/isotope ratio mass spectrometry.

    Science.gov (United States)

    McCullagh, James S O

    2010-03-15

    Liquid chromatography coupled to molecular mass spectrometry (LC/MS) has been a standard technique since the early 1970s but liquid chromatography coupled to high-precision isotope ratio mass spectrometry (LC/IRMS) has only been available commercially since 2004. This development has, for the first time, enabled natural abundance and low enrichment delta(13)C measurements to be applied to individual analytes in aqueous mixtures creating new opportunities for IRMS applications, particularly for the isotopic study of biological molecules. A growing number of applications have been published in a range of areas including amino acid metabolism, carbohydrates studies, quantification of cellular and plasma metabolites, dietary tracer and nucleic acid studies. There is strong potential to extend these to new compounds and complex matrices but several challenges face the development of LC/IRMS methods. To achieve accurate isotopic measurements, HPLC separations must provide baseline-resolution between analyte peaks; however, the design of current liquid interfaces places severe restrictions on compatible flow rates and in particular mobile phase compositions. These create a significant challenge on which reports associated with LC/IRMS have not previously focused. Accordingly, this paper will address aspects of chromatography in the context of LC/IRMS, in particular focusing on mixed-mode separations and their benefits in light of these restrictions. It aims to provide an overview of mixed-mode stationary phases and of ways to improve high aqueous separations through manipulation of parameters such as column length, temperature and mobile phase pH. The results of several practical experiments are given using proteogenic amino acids and nucleosides both of which are of noted importance in the LC/IRMS literature. This communication aims to demonstrate that mixed-mode stationary phases provide a flexible approach given the constraints of LC/IRMS interface design and acts as a

  6. Examining Changes in Radioxenon Isotope Activity Ratios during Subsurface Transport

    Science.gov (United States)

    Annewandter, Robert

    2014-05-01

    The Non-Proliferation Experiment (NPE) has demonstrated and modelled the usefulness of barometric pumping induced gas transport and subsequent soil gas sampling during On-Site inspections. Generally, gas transport has been widely studied with different numerical codes. However, gas transport of radioxenons and radioiodines in the post-detonation regime and their possible fractionation is still neglected in the open peer-reviewed literature. Atmospheric concentrations of the radioxenons Xe-135, Xe-133m, Xe-133 and Xe-131m can be used to discriminate between civilian releases (nuclear power plants or medical isotope facilities), and nuclear explosion sources. It is based on the multiple isotopic activity ratio method. Yet it is not clear whether subsurface migration of the radionuclides, with eventual release into the atmosphere, can affect the activity ratios due to fractionation. Fractionation can be caused by different mass diffusivities due to mass differences between the radionuclides. Cyclical changes in atmospheric pressure can drive subsurface gas transport. This barometric pumping phenomenon causes an oscillatoric flow in upward trending fractures or highly conductive faults which, combined with diffusion into the porous matrix, leads to a net transport of gaseous components - a so-called ratcheting effect. We use a general purpose reservoir simulator (Complex System Modelling Platform, CSMP++) which is recognized by the oil industry as leading in Discrete Fracture-Matrix (DFM) simulations. It has been applied in a range of fields such as deep geothermal systems, three-phase black oil simulations, fracture propagation in fractured, porous media, and Navier-Stokes pore-scale modelling among others. It is specifically designed to account for structurally complex geologic situation of fractured, porous media. Parabolic differential equations are solved by a continuous Galerkin finite-element method, hyperbolic differential equations by a complementary finite

  7. Ore lead isotope ratios in a continually changing Earth

    International Nuclear Information System (INIS)

    Cumming, G.L.; Richards, J.R.

    1975-01-01

    A critical reassessment of the construction of simple ore lead isotopic development curves is followed by three fresh approximations, all designed to involve the minimum possible number of assumptions. All are based on the Russell-Reynolds algorithm, when in its simplest form involves knowledge only of ratios, not of ages. The calculations are applied to a restricted class of ore leads, and the latest constant values for the U and Th isotopes are employed. Model I treats all data as being of equal weight, and shows that the deletion or inclusion of the Canyon Diablo meterorite data makes no difference to the derived parameters. Model II demonstrates that essentially the same parameters result if the simple curve is forced through the meteorite point; i.e. questions about homogeneity or otherwise of 'initial terrestrial'Pb are unimportant to the regression . Model III makes allowance for the known discrepancy in young 'model ages' by providing for a steady linear change in U/Pb and Th/Pb. The additional assumption of one fixed time point proves necessary. An age close to 430 m.y.for Captains Flat, N.S.W., yields acceptable age estimates for most other deposits investigated. No claim is made for the uniquences of this solution, but the derived evidence for steady growth in U/Ph accompanied by a slight decline in Th/U seems compatible with a crustal source for the lead ores concerned. (Auth.)

  8. Hydrogen isotope behavior in the first wall of JT-60U after deuterium plasma operation

    International Nuclear Information System (INIS)

    Oya, Y.; Tanabe, T.; Oyaidzu, M.; Shibahara, T.; Sugiyama, K.; Yoshikawa, A.; Onishi, Y.; Hirohata, Y.; Ishimoto, Y.; Yagyu, J.; Arai, T.; Masaki, K.; Okuno, K.; Miya, N.; Tanaka, S.

    2007-01-01

    Retention of hydrogen isotopes in the carbon (isotropic graphite) first wall tiles of JT-60U was studied by secondary ion mass spectrometry and thermal desorption spectroscopy. The surface morphology and erosion/deposition profiles of the tiles were characterized using scanning electron microscope and X-ray photoelectron spectroscopy. The upper area is mainly eroded, while the bottom area of the inboard wall is dominated by deposition. In contrast to the divertor area, hydrogen isotope retention in the eroded wall area was generally larger than that in the deposition dominated area. Measured near surface concentrations of hydrogen isotopes in the wall tiles, as well as the D/H ratios, were a little higher than those in the divertor area. This indicates direct implantation of high-energy D from NBI into the first wall. The lower temperature of the first wall relative to the divertor tiles would reduce desorption and/or replacement of implanted D by subsequent D or H impingement

  9. CARBON AND OXYGEN ISOTOPIC RATIOS FOR NEARBY MIRAS

    Energy Technology Data Exchange (ETDEWEB)

    Hinkle, Kenneth H. [National Optical Astronomy Observatory P.O. Box 26732, Tucson, AZ 85726 (United States); Lebzelter, Thomas [Department of Astrophysics, University of Vienna Türkenschanzstrasse 17, A-1180 Vienna (Austria); Straniero, Oscar, E-mail: khinkle@noao.edu, E-mail: thomas.lebzelter@univie.ac.at, E-mail: straniero@oa-teramo.inaf.it [INAF, Osservatorio Astronomico di Collurania I-64100 Teramo (Italy)

    2016-07-01

    Carbon and oxygen isotopic ratios are reported for a sample of 46 Mira and SRa-type variable asymptotic giant branch (AGB) stars. Vibration–rotation first and second-overtone CO lines in 1.5–2.5 μ m spectra were measured to derive isotopic ratios for {sup 12}C/{sup 13}C, {sup 16}O/{sup 17}O, and {sup 16}O/{sup 18}O. Comparisons with previous measurements for individual stars and with various samples of evolved stars, as available in the extant literature, are discussed. Models for solar composition AGB stars of different initial masses are used to interpret our results. We find that the majority of M-stars have main sequence masses ≤2 M {sub ⊙} and have not experienced sizable third dredge-up (TDU) episodes. The progenitors of the four S-type stars in our sample are slightly more massive. Of the six C-stars in the sample three have clear evidence relating their origin to the occurrence of TDU. Comparisons with O-rich presolar grains from AGB stars that lived before the formation of the solar system reveal variations in the interstellar medium chemical composition. The present generation of low-mass AGB stars, as represented by our sample of long period variables (LPVs), shows a large spread of {sup 16}O/{sup 17}O ratios, similar to that of group 1 presolar grains and in agreement with theoretical expectations for the composition of mass 1.2–2 M {sub ⊙} stars after the first dredge-up. In contrast, the {sup 16}O/{sup 18}O ratios of present-day LPVs are definitely smaller than those of group 1 grains. This is most probably a consequence of the the decrease with time of the {sup 16}O/{sup 18}O ratio in the interstellar medium due to the chemical evolution of the Milky Way. One star in our sample has an O composition similar to that of group 2 presolar grains originating in an AGB star undergoing extra-mixing. This may indicate that the extra-mixing process is hampered at high metallicity, or, equivalently, favored at low metallicity. Similarly to O

  10. Measurements of stable isotope ratios in milk samples from a farm placed in the mountains of Transylvania

    Energy Technology Data Exchange (ETDEWEB)

    Magdas, D. A., E-mail: gabriela.cristea@itim-cj.ro; Cristea, G., E-mail: gabriela.cristea@itim-cj.ro; Bot, A.; Puscas, R.; Radu, S.; Mirel, V. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania); Cordea, D. V.; Mihaiu, M. [University of Agricultural Science and Veterinary Medicine, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania)

    2013-11-13

    Product origin is of great importance for consumers especially because its association in consumer's perception with food quality, freedom from disease or pollution. Stable isotope ratio analysis is a powerful technique in food authenticity and traceability control which has been introduced within the European wine industry to ensure authenticity of wine provenance and to detect adulteration. Isotopic ratios measurements have also been successfully to other food commodities like: fruit juices, honey and dairy foods. The δ{sup 18}O and δ{sup 2}H content in milk water reflects the isotope composition of the ground water drunk by animals. Seasonal effects are also very important: in summer, milk water contains higher δ{sup 18}O and δ{sup 2}H values due to the fresh plants that are ate by animals. Relative carbon stable isotope abundances in total milk reflect the isotopic composition of the diet fed to the dairy cows. In this study the hydrogen, oxygen and carbon isotopic composition of 15 milk samples coming from a unit placed in the mountains of Transylvania was investigated. The distribution of the obtained isotopic values was than discussed taking into account that all the animals were feed with the same type of forage and consumed water was taken from the same source.

  11. Measurements of stable isotope ratios in milk samples from a farm placed in the mountains of Transylvania

    International Nuclear Information System (INIS)

    Magdas, D. A.; Cristea, G.; Bot, A.; Puscas, R.; Radu, S.; Mirel, V.; Cordea, D. V.; Mihaiu, M.

    2013-01-01

    Product origin is of great importance for consumers especially because its association in consumer's perception with food quality, freedom from disease or pollution. Stable isotope ratio analysis is a powerful technique in food authenticity and traceability control which has been introduced within the European wine industry to ensure authenticity of wine provenance and to detect adulteration. Isotopic ratios measurements have also been successfully to other food commodities like: fruit juices, honey and dairy foods. The δ 18 O and δ 2 H content in milk water reflects the isotope composition of the ground water drunk by animals. Seasonal effects are also very important: in summer, milk water contains higher δ 18 O and δ 2 H values due to the fresh plants that are ate by animals. Relative carbon stable isotope abundances in total milk reflect the isotopic composition of the diet fed to the dairy cows. In this study the hydrogen, oxygen and carbon isotopic composition of 15 milk samples coming from a unit placed in the mountains of Transylvania was investigated. The distribution of the obtained isotopic values was than discussed taking into account that all the animals were feed with the same type of forage and consumed water was taken from the same source

  12. Fractionation of hydrogen and oxygen isotopes between hydrated and free water molecules in aqueous urea solution

    International Nuclear Information System (INIS)

    Kakiuchi, M.; Matsuo, S.

    1985-01-01

    Ratios of D/H and 18 O/ 16 O in the vapor phase in equilibrium with aqueous urea solution with different urea molalities were measured at 15 and 25 0 C. Under the assumption that urea solutions consist of two species, i.e., the urea-water cluster and free water, the results are interpreted to give the average hydration number, i.e., the number of water molecules per urea molecule in the urea-water cluster. Good agreement was obtained for the hydration number estimated independently from hydrogen and oxygen isotopic fractions. On the basis of hydrogen isotopic data at 25 0 C, the average hydration number of urea in the cluster is 6.3 +/- 0.8 at 2.1 m and 2.75 +/- 0.08 at saturation (20.15 m). The corresponding average hydration numbers based on oxygen isotopic data were calculated to be 6.7 +/- 2.4 at 2.1 m and 2.75 +/- 0.25 at urea saturation. HD 16 O is enriched in the urea-water cluster and H 2 18 O is enriched in free water. Isotopic partitioning between the cluster and free water is markedly different from those between hydration spheres and free water in aqueous electrolyte solutions. 29 references, 6 figures, 5 tables

  13. Sulfur isotopic ratios of molybdenites from the Hida Mountains, Japan

    International Nuclear Information System (INIS)

    Ishihara, Shunso; Harayama, Satoru; Sasaki, Akira.

    1990-01-01

    Molybdenites occurring in Paleogene granitoids of the Northern Japan Alps of the Hida Mountains were analyzed for δ 34 S CDT at seven localities. The sulfur isotopic ratios vary from 3.0 to 6.4 per mille, which are within the range of ore molybdenites from the magnetite-series granitic terrane of the Sanin district, indicating that the Hida Mountains and Sanin district belong to the same metallogenic province. Porphyry-type molybdenite from the Kamioka lead-zinc mine has the δ 34 S value of 1.4 per mille. Sulfur of the molybdenite is not derived from the Jurassic Funatsu granitoids but brought up by the latest Cretaceous ilmenite-series magma, prior to the main Paleogene magnetite-series magmatism. (author)

  14. Simulation of startup period of hydrogen isotope separation distillation column

    International Nuclear Information System (INIS)

    Sazonov, A.B.; Kagramanov, Z.G.; Magomedbekov, Eh.P.

    2003-01-01

    Kinetic procedure for the mathematical simulation of start-up regime of rectification columns for molecular hydrogen isotope separation was developed. Nonstationary state (start-up period) of separating column for rectification of multi-component mixture was calculated. Full information on equilibrium and kinetic physicochemical properties of components in separating mixtures was used for the calculations. Profile of concentration of components by height of column in task moment of time was calculated by means of differential equilibriums of nonstationary mass transfer. Calculated results of nonstationary state of column by the 2 m height, 30 mm diameter during separation of the mixture: 5 % protium, 70 % deuterium, 25 % tritium were illustrated [ru

  15. Measurement of the isotope ratio of acetic acid in vinegar by HS-SPME-GC-TC/C-IRMS.

    Science.gov (United States)

    Hattori, Ryota; Yamada, Keita; Shibata, Hiroki; Hirano, Satoshi; Tajima, Osamu; Yoshida, Naohiro

    2010-06-23

    Acetic acid is the main ingredient of vinegar, and the worth of vinegar often depends on the fermentation of raw materials. In this study, we have developed a simple and rapid method for discriminating the fermentation of the raw materials of vinegar by measuring the hydrogen and carbon isotope ratio of acetic acid using head space solid-phase microextraction (HS-SPME) combined with gas chromatography-high temperature conversion or combustion-isotope ratio mass spectrometry (GC-TC/C-IRMS). The measurement of acetic acid in vinegar by this method was possible with repeatabilities (1sigma) of +/-5.0 per thousand for hydrogen and +/-0.4 per thousand for carbon, which are sufficient to discriminate the origin of acetic acid. The fermentation of raw materials of several vinegars was evaluated by this method.

  16. Light hydrogen isotopes in the single - walled carbon nano tube

    International Nuclear Information System (INIS)

    Khugaev, A.V.; Sultanov, R.A.; Guster, D.

    2007-01-01

    Full text: Progress of our understanding of the molecular hydrogen behavior in the nano tube interior open an intriguing possibility for the applications of these knowledge's to the solution of the hydrogen storage problem and light isotopes gas selectivity. That can strongly change the situation at the energy production in the world and completely change our civil life. These investigations underline the influence of the quantum effects on the properties of molecular hydrogen in the nano tube interior and it leads to the pure quantum-mechanical reformulation of the problem for the hydrogen behavior inside carbon nano tube as a problem of molecular quantum system behavior in the external field induced by the regular nano tube surface. In the present paper the molecular hydrogen behavior in the carbon nano tube was considered in the simple quantum mechanical manner. The main attention was paid to the investigation of the quantum sieving selectivity in the dependence of nano tube composition, radius and symmetry properties. For the interaction potential between hydrogen and nano tube surface was taken some phenomenological LJ(12,6) - (Lennard - Jones) potential and the external field induced by the nano tube in its interior is considered as a simple sum over the all nano tube carbon atoms. Influence of the structure of rotation (vibration) spectrum of the energy levels of diatomic molecules, such as H 2 , HD and D 2 on the final results and finite size of the nano tube along the axis of symmetry, its boundary effects is discussed in details. Thermal oscillations of nano tube surface were considered separately in the dependence of the temperature gradient along of the axis of symmetry

  17. Multisample conversion of water to hydrogen by zinc for stable isotope determination

    Science.gov (United States)

    Kendall, C.; Coplen, T.B.

    1985-01-01

    Two techniques for the conversion of water to hydrogen for stable isotope ratio determination have been developed that are especially suited for automated multisample analysis. Both procedures involve reaction of zinc shot with a water sample at 450 ??C. in one method designed for water samples in bottles, the water is put in capillaries and is reduced by zinc in reaction vessels; overall savings in sample preparation labor of 75% have been realized over the standard uranium reduction technique. The second technique is for waters evolved under vacuum and is a sealed-tube method employing 9 mm o.d. quartz tubing. Problems inherent with zinc reduction include surface inhomogeneity of the zinc and exchange of hydrogen both with the zinc and with the glass walls of the vessels. For best results, water/zinc and water/glass surface area ratios of vessels should be kept as large as possible.

  18. Sims Analysis of Water Abundance and Hydrogen Isotope in Lunar Highland Plagioclase

    Science.gov (United States)

    Hui, Hejiu; Guan, Yunbin; Chen, Yang; Peslier, Anne H.; Zhang, Youxue; Liu, Yang; Rossman, George R.; Eiler, John M.; Neal, Clive R.

    2015-01-01

    The detection of indigenous water in mare basaltic glass beads has challenged the view established since the Apollo era of a "dry" Moon. Since this discovery, measurements of water in lunar apatite, olivine-hosted melt inclusions, agglutinates, and nominally anhydrous minerals have confirmed that lunar igneous materials contain water, implying that some parts of lunar mantle may have as much water as Earth's upper mantle. The interpretation of hydrogen (H) isotopes in lunar samples, however, is controversial. The large variation of H isotope ratios in lunar apatite (delta Deuterium = -202 to +1010 per mille) has been taken as evidence that water in the lunar interior comes from the lunar mantle, solar wind protons, and/or comets. The very low deuterium/H ratios in lunar agglutinates indicate that solar wind protons have contributed to their hydrogen content. Conversely, H isotopes in lunar volcanic glass beads and olivine-hosted melt inclusions being similar to those of common terrestrial igneous rocks, suggest a common origin for water in both Earth and Moon. Lunar water could be inherited from carbonaceous chondrites, consistent with the model of late accretion of chondrite-type materials to the Moon as proposed by. One complication about the sources of lunar water, is that geologic processes (e.g., late accretion and magmatic degassing) may have modified the H isotope signatures of lunar materials. Recent FTIR analyses have shown that plagioclases in lunar ferroan anorthosite contain approximately 6 ppm H2O. So far, ferroan anorthosite is the only available lithology that is believed to be a primary product of the lunar magma ocean (LMO). A possible consequence is that the LMO could have contained up to approximately 320 ppm H2O. Here we examine the possible sources of water in the LMO through measurements of water abundances and H isotopes in plagioclase of two ferroan anorthosites and one troctolite from lunar highlands.

  19. Laser-induced separation of hydrogen isotopes in the liquid phase

    International Nuclear Information System (INIS)

    Beattie, W.; Freund, S.; Holland, R.; Maier, W.

    1980-01-01

    A process for separating hydrogen isotopes which comprises (A) forming a liquid phase of hydrogen-bearing feedstock compound at a temperature at which the spectral features of the feedstock compound are narrow enough or the absorption edges sharp enough to permit spectral features corresponding to the different hydrogen isotopes to be separated to be distinguished, (B) irradiating the liquid phase at said temperature with monochromatic radiation of a first wavelength which selectively or at least preferentially excites those molecules of said feedstock compound containing a first hydrogen isotope, and (C) subjecting the excited molecules to physical or chemical processes or a combination thereof whereby said first hydrogen isotope contained in said excited molecules is separated from other hydrogen isotopes contained in the unexcited molecules in said liquid phase

  20. Chemical equilibria relating the isotopic hydrogens at low temperatures

    International Nuclear Information System (INIS)

    Pyper, J.W.; Souers, P.C.

    1976-01-01

    Hydrogen fusion will require a fuel mixture of liquefied or frozen D 2 and T 2 . The composition of this fuel mixture is described by the equilibrium constant K/sub DT/. The theory of isotopic exchange reactions is discussed as applied to the hydrogen isotopes. A literature survey of the values of K/sub HD/, K/sub HT/, and K/sub DT/ found no values of K/sub DT/ for temperatures below 25 0 K and no values of K/sub HD/ and K/sub HT/ for temperatures below 50 0 K. The existing data are critically evaluated, and simplified formulas for the three equilibrium constants in the temperature range 50 to 300 0 K are derived from them. Harmonic approximation theory with rotational correction was used to calculate values of K/sub HD/, K/sub HT/, and K/sub DT/ in the temperature range 4.2 to 50 0 K. It is found that K/sub DT/ = 2.995 exp(-10.82/T) in the temperature range 16.7 to 33.3 0 K to an accuracy of 1%. Tables, graphs, and equations of K/sub HD/, K/sub HT/, and K/sub DT/ are given for the temperature range 4.2 to 50 0 K. 27 references, 14 tables, 8 figures

  1. Hydrogen isotopic exchange reaction in a trickle-bed

    International Nuclear Information System (INIS)

    Paek, Seung Woo; Ahn, Do Hee; Kim, Kwang Rag; Lee, Min Soo; Yim, Sung Paal; Chung, Hong Suk

    2005-01-01

    The CECE (Combined Electrolysis Catalytic Exchange) with a hydrophobic catalyst is ideally suited for extracting tritium from water because of its high separation factor and mild operating conditions. This process for different hydrogen isotope applications has been developed by AECL. A laboratory scale CECE was built and operated at Mound Laboratory. Belgium and Japan have also developed independently similar processes which are based on a hydrophobic catalyst. The CECE column is composed of an electrolysis cell and a liquid phase catalytic exchange column. The liquid phase catalytic exchange columns having various structures were developed; and it has been recognized that a multistage type and a trickle-bed type are promising. The multistage type gave more successful results than the trickle-bed type. However, the structure of the column is complicated. The trickle-bed type has a significant advantage in that the structure of the column is quite simple: the hydrophobic catalysts or the catalysts and packings are packed within the column. This structure would lead us to a smaller column height than the multistage type. This paper deals with the experiment for the hydrogen isotope exchange in a trickle-bed reactor packed with a hydrophobic catalyst and the design of the catalytic column for the CECE to tritium recovery from light water

  2. Hydrogen isotopic exchange reaction in a trickle-bed

    Energy Technology Data Exchange (ETDEWEB)

    Paek, Seung Woo; Ahn, Do Hee; Kim, Kwang Rag; Lee, Min Soo; Yim, Sung Paal; Chung, Hong Suk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2005-07-01

    The CECE (Combined Electrolysis Catalytic Exchange) with a hydrophobic catalyst is ideally suited for extracting tritium from water because of its high separation factor and mild operating conditions. This process for different hydrogen isotope applications has been developed by AECL. A laboratory scale CECE was built and operated at Mound Laboratory. Belgium and Japan have also developed independently similar processes which are based on a hydrophobic catalyst. The CECE column is composed of an electrolysis cell and a liquid phase catalytic exchange column. The liquid phase catalytic exchange columns having various structures were developed; and it has been recognized that a multistage type and a trickle-bed type are promising. The multistage type gave more successful results than the trickle-bed type. However, the structure of the column is complicated. The trickle-bed type has a significant advantage in that the structure of the column is quite simple: the hydrophobic catalysts or the catalysts and packings are packed within the column. This structure would lead us to a smaller column height than the multistage type. This paper deals with the experiment for the hydrogen isotope exchange in a trickle-bed reactor packed with a hydrophobic catalyst and the design of the catalytic column for the CECE to tritium recovery from light water.

  3. Hydrogen isotope separation experience at the Savannah River Site

    International Nuclear Information System (INIS)

    Lee, M.W.

    1993-01-01

    Savannah River Site (SRS) is a sole producer of tritium for US Weapons Program. SRS has built Facilities, developed the tritium handling processes, and operated safely for the last forty years. Tritium is extracted from the irradiated reactor target, purified, mixed with deuterium, and loaded to the booster gas bottle in the weapon system for limited lifetime. Tritium is recovered from the retired bottle and recycled. Newly produced tritium is branded into the recycled tritium. One of the key process is the hydrogen isotope separation that tritium is separated from deuterium and protium. Several processes have been used for the hydrogen isotope separation at SRS: Thermal Diffusion Column (TD), Batch Cryogenic Still (CS), and Batch Chromatography called Fractional Sorption (FS). TD and CS requires straight vertical columns. The overall system separation factor depends on the length of the column. These are three story building high and difficult to put in glove box. FS is a batch process and slow operation. An improved continuous chromatographic process called Thermal Cycling Absorption Process (TCAP) has been developed. It is small enough to be about to put in a glove box yet high capacity comparable to CS. The SRS tritium purification processes can be directly applicable to the Fusion Fuel Cycle System of the fusion reactor

  4. Nanoporous materials for hydrogen storage and H2/D2 isotope separation

    International Nuclear Information System (INIS)

    Oh, Hyunchul

    2014-01-01

    uptake in Pt doped carbon over pristine carbon is observed indicating a limited role of the spillover effect for practical hydrogen storage. Secondly, the synthesis of a new organic-inorganic hybrid material ''metal doped covalent-organic framework (COF)'' via gas phase infiltration method is presented. In this way, COFs can be used as novel scaffolds for the stabilization of nanoparticles with a nearly mono-dispersed size and homogeneous distribution. At room temperature, the hydrogen storage capacity of Pd doped COFs is enhanced by a factor of 2∝3 compared to the pristine COFs. This significant enhancement of Pd doped COFs can be assigned to the catalytic hydrogenation of organic fragments such as bicyclopentadiene originating from the Pd precursor. Chapter 5 focuses on separation of hydrogen isotopes with nanoporous materials. Separating gaseous mixtures that consist of very similar particles (such as mixture of light gas isotopes or mixtures of noble gases) is one of the challenges in modern separation technology. Especially D 2 /H 2 separation is a difficult task since its size, shape and thermodynamic properties share each other. Recently, quantum sieving in confined space has received increased attention as an efficient method for hydrogen isotope separation. Despite many theoretical calculations, however, it has been difficult to identify a feasible microporous material up to now. Among various porous materials, the novel class of microporous framework materials (COFs, ZIFs and MOFs) is considered as the most promising approach for isotope sieving due to ultra-high porosity and uniform pore size which can be tailored in these materials. Hence, one focus is the investigation of the fundamental correlation between D 2 /H 2 molar ratio and pore size at optimized operating conditions by using different nanoporous frameworks. It reveals that the D 2 /H 2 molar ratio is strongly depending on pore size, pressure and temperature. The experiments indicate clearly that

  5. Boron isotope ratios of surface waters in Guadeloupe, Lesser Antilles

    Energy Technology Data Exchange (ETDEWEB)

    Louvat, Pascale, E-mail: louvat@ipgp.fr [Geochimie et Cosmochimie, IPGP, Universite Paris Diderot, Sorbonne Paris Cite, UMR 7154 CNRS, 75005 Paris (France); Gaillardet, Jerome; Paris, Guillaume; Dessert, Celine [Geochimie et Cosmochimie, IPGP, Universite Paris Diderot, Sorbonne Paris Cite, UMR 7154 CNRS, 75005 Paris (France)

    2011-06-15

    Highlights: > Rivers outer of hydrothermal areas have d11B around 40 per mille and [B] of 10-31 {mu}g/L. > Thermal springs have d11B of 8-15 per mille and [B] between 250 and 1000 {mu}g/L. > With Na, SO{sub 4} and Cl, boron shows mixing of rain, low and high-T weathering inputs. > Guadeloupe rivers and thermal springs have d11B 20-40 per mille higher than the local rocks. > Solid-solution fractionation during weathering pathways may explain this gap of d11B. - Abstract: Large variations are reported in the B concentrations and isotopic ratios of river and thermal spring waters in Guadeloupe, Lesser Antilles. Rivers have {delta}{sup 11}B values around 40 per mille and B concentrations lower than 30 {mu}g/L, while thermal springs have {delta}{sup 11}B of 8-15 per mille and B concentrations of 250-1000 {mu}g/L. River samples strongly impacted by hydrothermal inputs have intermediate {delta}{sup 11}B and B contents. None of these surface water samples have {delta}{sup 11}B comparable to the local unweathered volcanic rocks (around 0 per mille), implying that a huge isotopic fractionation of 40 per mille takes place during rock weathering, which could be explained by preferential incorporation of {sup 10}B during secondary mineral formation and adsorption on clays, during rock weathering or in the soils. The soil-vegetation B cycle could also be a cause for such a fractionation. Atmospheric B with {delta}{sup 11}B of 45 per mille represents 25-95% of the river B content. The variety of the thermal spring chemical composition renders the understanding of B behavior in Guadeloupe hydrothermal system quite difficult. Complementary geochemical tracers would be helpful.

  6. Boron isotope ratios of surface waters in Guadeloupe, Lesser Antilles

    International Nuclear Information System (INIS)

    Louvat, Pascale; Gaillardet, Jerome; Paris, Guillaume; Dessert, Celine

    2011-01-01

    Highlights: → Rivers outer of hydrothermal areas have d11B around 40 per mille and [B] of 10-31 μg/L. → Thermal springs have d11B of 8-15 per mille and [B] between 250 and 1000 μg/L. → With Na, SO 4 and Cl, boron shows mixing of rain, low and high-T weathering inputs. → Guadeloupe rivers and thermal springs have d11B 20-40 per mille higher than the local rocks. → Solid-solution fractionation during weathering pathways may explain this gap of d11B. - Abstract: Large variations are reported in the B concentrations and isotopic ratios of river and thermal spring waters in Guadeloupe, Lesser Antilles. Rivers have δ 11 B values around 40 per mille and B concentrations lower than 30 μg/L, while thermal springs have δ 11 B of 8-15 per mille and B concentrations of 250-1000 μg/L. River samples strongly impacted by hydrothermal inputs have intermediate δ 11 B and B contents. None of these surface water samples have δ 11 B comparable to the local unweathered volcanic rocks (around 0 per mille), implying that a huge isotopic fractionation of 40 per mille takes place during rock weathering, which could be explained by preferential incorporation of 10 B during secondary mineral formation and adsorption on clays, during rock weathering or in the soils. The soil-vegetation B cycle could also be a cause for such a fractionation. Atmospheric B with δ 11 B of 45 per mille represents 25-95% of the river B content. The variety of the thermal spring chemical composition renders the understanding of B behavior in Guadeloupe hydrothermal system quite difficult. Complementary geochemical tracers would be helpful.

  7. Isotope effect in the diffusion of hydrogen and deuterium in polymers

    Energy Technology Data Exchange (ETDEWEB)

    Toi, K.; Takeuchi, K.; Tokuda, T.

    1980-02-01

    Temperature dependences of diffusion and permeation coefficients of hydrogen and deuterium in glassy and rubbery polymer films have been measured. The size of the free volume element in rubbery polymers has been calculated according to the theory of Frisch and Rogers for the quantum isotope effect, but the free volume is too large for precise calculation below the glass-transition temperature. The cooperative movement of segments is also discussed using the ratio of preexponential factors for diffusion mechanisms above and below the glass-transition temperature.

  8. Stable carbon isotopic composition of gasolines determined by isotope ratio monitoring gas chromatography mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Smallwood, B.J.; Philp, R.P.; Allen, J.D. [University of Oklahoma, Norman, OK (United States). School of Geology and Geophysics

    2002-07-01

    A large number of underground gasoline storage facilities in the United States continuously leak gasoline into the subsurface, which makes gasoline a major groundwater contaminant. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) are used currently to characterize contaminated groundwater and soils. Correlations of contaminants with suspected source(s) are extremely difficult by these techniques because many gasolines have similar hydrocarbon distributions. The present study applied the technique of isotope ratio monitoring gas chromatography-mass spectrometry (irmGC-MS) to 19 gasoline samples from different areas of the USA. This allows a much better correlation of gasoline contaminants to source. Data obtained indicate a wide range of {sup {delta}}{sup 13}C values for 16 ubiquitous compounds in the gasolines. The majority of samples could be distinguished from each other on the basis of {sup {delta}}{sup 13}C hydrocarbon composition. The oxygenated additive methyl tertiary butyl ether (MTBE) was present in ten of the gasolines analyzed, and had a relatively narrow range of {sup {delta}}{sup 13}C values (-30.4 to -28.3 per mille). Preliminary investigations were also made to determine the extent of carbon isotopic fractionation after simple water washing and evaporation experiments. Results indicate that the majority of compounds did not undergo significant carbon isotopic fractionation as a result of these processes. (author)

  9. Titan's Carbon Isotopic Ratio: A Clue To Atmospheric Evolution?

    Science.gov (United States)

    Nixon, C. A.; Jennings, D. E.; Romani, P. N.; Jolly, A.; Teanby, N. A.; Irwin, P. G.; Bézard, B.; Vinatier, S.; Coustenis, A.; Flasar, F. M.

    2009-12-01

    In this presentation we describe the latest results to come from Cassini CIRS and ground-based telescopic measurements of Titan's 12C/13C ratio in atmospheric molecules, focusing on hydrocarbons. Previously, the Huygens GCMS instrument measured 12CH4/13CH4 to be 82±1 (Niemann et al., Nature, 438, 779-784, 2005), substantially and significantly lower than the VPDB inorganic Earth standard of 89.4. It is also at odds with measurements for the giant planets. Cassini CIRS infrared spectra have confirmed this enhancement in 13CH4, but also revealed that the ratio in ethane, the major photochemical product of methane photolysis, does not appear enhanced (90±7) (Nixon et al.. Icarus, 195, 778-791, 2008) and is compatible with the terrestrial and combined giant planet value (88±7, Sada et al., Ap. J., 472, p. 903-907, 1996). Recently-published results from spectroscopy using the McMath-Pierce telescope at Kitt Pitt (Jennings et al., JCP, 2009, in press) have confirmed this deviation between methane and ethane, and an explanation has been proposed. This invokes a kinetic isotope effect (KIE) in the abstraction of methane by ethynyl, a major ethane formation pathway, to preferentially partition 12C into ethane and leave an enhancement in atmospheric 13CH4 relative to the incoming flux from the reservoir. Modeling shows that a steady-state solution exists where the 12C/13C methane is decreased from the reservoir value by exactly the KIE factor (the ratio of 12CH4 to 13CH4 abstraction reaction rates): which is plausibly around 1.08, very close to the observed amount. However, a second solution exists in which we are observing Titan about ~1 methane lifetime after a major injection of methane into the atmosphere which is rapidly being eliminated. Updated measurements by Cassini CIRS of both the methane and ethane 12C/13C ratios will be presented, along with progress in interpreting this ratio. In addition, we summarize the 12C/13C measurements by CIRS in multiple other Titan

  10. Potential application of gas chromatography to the analysis of hydrogen isotopes

    International Nuclear Information System (INIS)

    Warner, D.K.; Sprague, R.E.; Bohl, D.R.

    1976-01-01

    Gas chromatography is used at Mound Laboratory for the analysis of hydrogen isotopic impurities in gas mixtures. This instrumentation was used to study the applicability of the gas chromatography technique to the determination of the major components of hydrogen isotopic gas mixtures. The results of this study, including chromatograms and precision data, are presented

  11. Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS)--preliminary study on TATP and PETN.

    Science.gov (United States)

    Benson, Sarah J; Lennard, Christopher J; Maynard, Philip; Hill, David M; Andrew, Anita S; Roux, Claude

    2009-06-01

    The application of isotopic techniques to investigations requiring the provision of evidence to a Court is limited. The objective of this research was to investigate the application of light stable isotopes and isotope ratio mass spectrometry (IRMS) to solve complex forensic cases by providing a level of discrimination not achievable utilising traditional forensic techniques. Due to the current threat of organic peroxide explosives, such as triacetone triperoxide (TATP), research was undertaken to determine the potential of IRMS to differentiate samples of TATP that had been manufactured utilising different starting materials and/or manufacturing processes. In addition, due to the prevalence of pentaerythritoltetranitrate (PETN) in detonators, detonating cord, and boosters, the potential of the IRMS technique to differentiate PETN samples from different sources was also investigated. Carbon isotope values were measured in fourteen TATP samples, with three definite groups appearing in the initial sample set based on the carbon data alone. Four additional TATP samples (in a second set of samples) were distinguishable utilising the carbon and hydrogen isotopic compositions individually, and also in combination with the oxygen isotope values. The 3D plot of the carbon, oxygen and hydrogen data demonstrated the clear discrimination of the four samples of TATP. The carbon and nitrogen isotope values measured from fifteen PETN samples, allowed samples from different sources to be readily discriminated. This paper demonstrates the successful application of IRMS to the analysis of explosives of forensic interest to assist in discriminating samples from different sources. This research represents a preliminary evaluation of the IRMS technique for the measurement of stable isotope values in TATP and PETN samples, and supports the dedication of resources for a full evaluation of this application in order to achieve Court reportable IRMS results.

  12. Isotopic ratios of 129I/127I in mammalian thyroid glands in Japan

    International Nuclear Information System (INIS)

    Seki, R.; Hatano, T.

    1994-01-01

    The isotopic ratios of 129 I/ 127 I in cattle thyroid glands collected from various areas of Japan were measured by neutron activation analysis with combustion pre-treatment. Pig and human thyroid glands were also analyzed by the same method. The iodine isotopic ratio in cattle thyroid glands in Japan is comparable with that observed in Europe. The isotopic ratio in human thyroid glands in Japan is remarkably lower than that in Europe, which has been reported to be comparable to that of cattle. The isotopic ratio in pig thyroid glands is also lower than that in cattle. (author) 7 refs.; 3 figs.; 5 tabs

  13. Development, optimisation, and application of ICP-SFMS methods for the measurement of isotope ratios

    International Nuclear Information System (INIS)

    Stuerup, S.

    2000-07-01

    The measurement of isotopic composition and isotope ratios in biological and environmental samples requires sensitive, precise, and accurate analytical techniques. The analytical techniques used are traditionally based on mass spectrometry, among these techniques is the ICP-SFMS technique, which became commercially available in the mid 1990s. This technique is characterised by high sensitivity, low background, and the ability to separate analyte signals from spectral interferences. These features are beneficial for the measurement of isotope ratios and enable the measurement of isotope ratios of elements, which it has not previously been possible to measure due to either spectral interferences or poor sensitivity. The overall purpose of the project was to investigate the potential of the single detector ICP-SFMS technique for the measurement of isotope ratios in biological and environmental samples. One part of the work has focused on the fundamental aspects of the ICP-SFMS technique with special emphasize on the features important to the measurement of isotope ratios, while another part has focused on the development, optimisation and application of specific methods for the measurement of isotope ratios of elements of nutritional interest and radionuclides. The fundamental aspects of the ICP-SFMS technique were investigated theoretically and experimentally by the measurement of isotope ratios applying different experimental conditions. It was demonstrated that isotope ratios could be measured reliably using ICP-SFMS by educated choice of acquisition parameters, scanning mode, mass discrimination correction, and by eliminating the influence of detector dead time. Applying the knowledge gained through the fundamental study, ICP-SFMS methods for the measurement of isotope ratios of calcium, zinc, molybdenum and iron in human samples and a method for the measurement of plutonium isotope ratios and ultratrace levels of plutonium and neptunium in environmental samples

  14. Efficiency of Al2O3 supported palladium sorbents in the process of hydrogen isotope exchange

    International Nuclear Information System (INIS)

    Andreev, B.M.; Perevezentsev, A.N.; Yasenkov, V.I.

    1981-01-01

    It is found that in the hydrogen-palladium system while applying the metal to aluminium oxide a considerable increase of the heterogeneous hydrogen isotopic exchange rate is observed due to the increase of its specific surface at 167-298 K temperatures and 350-500 Torr hydrogen pressures. It is shown that in the process of thermal treatment of the supported palladium sorbent resulting in reconstruction of the carrier porous structure, as well as in increasing the metal crystal size, the change of the stage, limiting the isotopic exchange process, occurs. The values of the rate and energy of activation of the hydrogen isotopic exchange are presented [ru

  15. Authenticity and traceability of vanilla flavors by analysis of stable isotopes of carbon and hydrogen.

    Science.gov (United States)

    Hansen, Anne-Mette Sølvbjerg; Fromberg, Arvid; Frandsen, Henrik Lauritz

    2014-10-22

    Authenticity and traceability of vanilla flavors were investigated using gas chromatography-isotope ratio mass spectrometry (GC-IRMS). Vanilla flavors produced by chemical synthesis (n = 2), fermentation (n = 1), and extracted from two different species of the vanilla orchid (n = 79) were analyzed. The authenticity of the flavor compound vanillin was evaluated on the basis of measurements of ratios of carbon stable isotopes (δ(13)C). It was found that results of δ(13)C for vanillin extracted from Vanilla planifolia and Vanilla tahitensis were significantly different (t test) and that it was possible to differentiate these two groups of natural vanillin from vanillin produced otherwise. Vanilla flavors were also analyzed for ratios of hydrogen stable isotopes (δ(2)H). A graphic representation of δ(13)C versus δ(2)H revealed that vanillin extracted from pods grown in adjacent geographic origins grouped together. Accordingly, values of δ(13)C and δ(2)H can be used for studies of authenticity and traceability of vanilla flavors.

  16. Covariance of oxygen and hydrogen isotopic composition in plant water: Species effects

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, L.W.; DeNiro, M.J. (Univ. of California, Los Angeles (United States))

    1989-12-01

    Leaf water becomes enriched in the heavy isotopes of oxygen and hydrogen during evapotranspiration. The magnitude of the enrichment has been shown to be influenced by temperature and humidity, but the effects of species-specific factors on leaf water enrichment of D and {sup 18}O have not been studied for different plants growing together. To learn whether leaf water enrichment patterns and processes for D and {sup 18}O are different for individual species growing under the same environmental conditions the authors tested the proposal that leaf waters in plants with crassulacean acid metabolism (CAM) show high sloped (m in the leaf water equation {delta}D = m {delta}{sup 18}O + b) than in C{sub 3} plants. They determined the relationships between the stable hydrogen ({delta}D) and oxygen ({delta}{sup 18}O) isotope ratios of leaf waters collected during the diurnal cycle of evapotranspiration for Yucca schidigera, Ephedra aspera, Agave deserti, Prunus ilicifolia, Yucca whipplei, Heteromeles arbutifolia, Dyckia fosteriana, Simmondsia chinensis, and Encelia farinosa growing at two sites in southern California. The findings indicate that m in the aforementioned equation is related to the overall residence time for water in the leaf and proportions of water subjected to repeated evapotranspiration enrichments of heavy isotopes.

  17. Peculiarities of spectroscopic determination of the isotopic hydrogen composition in a mixture with neon and argon

    International Nuclear Information System (INIS)

    Nemets, V.M.; Petrov, A.A.; Solov'ev, A.A.

    1987-01-01

    The dependence of the relative intensity of atomic lines of hydrogen isotopes in the mixture with neon and argon during excitation in a high-frequency discharge under medium and high pressures is investigated. A physical model is suggested for processes determining the isotopic effects in the atomic hydrogen spectrum due to isotopic differences in velocity constants of dissociation-association, transfer and ionic-molecular reactions in a gas discharge plasma

  18. Structure and isotopic ratios of aliphatic side chains in the insoluble organic matter of the Murchison carbonaceous chondrite

    Science.gov (United States)

    Huang, Yongsong; Alexandre, Marcelo R.; Wang, Yi

    2007-07-01

    We report in this paper the first molecular and isotopic characterization of individual aliphatic side chains from the insoluble organic matter (IOM) in the Murchison carbonaceous chondrite using a novel combined approach of RuO 4 oxidation and solid phase microextraction (SPME). The aliphatic side chains in the IOM of Murchison were first released by oxidizing aromatic structures using RuO 4. Because the IOM of carbonaceous chondrites contains predominantly short (C 1 to C 9) aliphatic substitutions, the resulting low molecular weight monocarboxylic acids (MCAs) are highly volatile and water-soluble. The conventional aqueous extraction and derivatization procedures following RuO 4 oxidation are unable to recover MCAs for subsequent analyses. We overcame this problem by employing SPME to directly capture the MCAs from the aqueous solution. We selected a SPME fiber with greater affinity for longer chain monoacids to compensate for the exponential decline of monoacid concentrations with increasing carbon numbers in meteorite IOM, allowing more accurate identification and quantification for the less abundant monoacids. We also determined the carbon and hydrogen isotopic ratios of individual MCAs derived from Murchinson IOM. Our results reveal significant similarity in both molecular structures and hydrogen isotopic ratios between the IOM aliphatic side chains and water-soluble MCAs in Murchison, suggesting that these compounds had common precursors. Our combined new approach of RuO 4 oxidation-SPME provides a new way to probe the molecular and isotopic characteristics of aliphatic side chains in carbonaceous chondrites.

  19. Covariance of oxygen and hydrogen isotopic compositions in plant water: species effects

    International Nuclear Information System (INIS)

    Cooper, L.W.; DeNiro, M.J.

    1989-01-01

    Leaf water becomes enriched in the heavy isotopes of oxygen and hydrogen during evapotranspiration. The magnitude of the enrichment has been shown to be influenced by temperature and humidity, but the effects of species—specific factors on leaf water enrichment of D and 18 O have not been studied for different plants growing together. Accordingly, to learn whether leaf water enrichment patterns and processes for D and 18 O are different for individual species growing under the same environmental conditions we tested the proposal that leaf waters in plants with crassulacean acid metabolism (CAM) show higher slopes (m in the leaf water equation °D = m ° 18 O + b) than in C 3 plants. We determined the relationships between the stable hydrogen (°D) and oxygen (° 18 O) isotope ratios of leaf waters collected during the diurnal cycle of evapotranspiration for Yucca schidigera, Ephedra aspera, Agave deserti, Prunus ilicifolia, Yucca whipplei, Heteromeles arbutifolia, Dyckia fosteriana, Simmondsia chinensis, and Encelia farinosa growing at two sites in southern California. Slopes (m in the above leaf water equation) ranged from 1.50 to 3.21, compared to °8 for meteoric water, but differences in slope could not be attributed to carboxylation pathway (CAM vs. C 3 ) nor climate (coastal California vs. Sonoran Desert). Higher slopes were correlated with greater overall ranges of leaf water enrichment of D and 18 O. Water in plants with higher slopes also differed most from unaltered meteoric water. Leaf water isotope ratios in plants with lower slopes were better correlated with temperature and humidity. The findings indicate that m in the aforementioned equation is related to the overall residence time for water in the leaf and proportions of water subjected to repeated evapotranspiration enrichments of heavy isotopes

  20. A sorghum (Sorghum bicolor mutant with altered carbon isotope ratio.

    Directory of Open Access Journals (Sweden)

    Govinda Rizal

    Full Text Available Recent efforts to engineer C4 photosynthetic traits into C3 plants such as rice demand an understanding of the genetic elements that enable C4 plants to outperform C3 plants. As a part of the C4 Rice Consortium's efforts to identify genes needed to support C4 photosynthesis, EMS mutagenized sorghum populations were generated and screened to identify genes that cause a loss of C4 function. Stable carbon isotope ratio (δ13C of leaf dry matter has been used to distinguishspecies with C3 and C4 photosynthetic pathways. Here, we report the identification of a sorghum (Sorghum bicolor mutant with a low δ13C characteristic. A mutant (named Mut33 with a pale phenotype and stunted growth was identified from an EMS treated sorghum M2 population. The stable carbon isotope analysis of the mutants showed a decrease of 13C uptake capacity. The noise of random mutation was reduced by crossing the mutant and its wildtype (WT. The back-cross (BC1F1 progenies were like the WT parent in terms of 13C values and plant phenotypes. All the BC1F2 plants with low δ13C died before they produced their 6th leaf. Gas exchange measurements of the low δ13C sorghum mutants showed a higher CO2 compensation point (25.24 μmol CO2.mol-1air and the maximum rate of photosynthesis was less than 5μmol.m-2.s-1. To identify the genetic determinant of this trait, four DNA pools were isolated; two each from normal and low δ13C BC1F2 mutant plants. These were sequenced using an Illumina platform. Comparison of allele frequency of the single nucleotide polymorphisms (SNPs between the pools with contrasting phenotype showed that a locus in Chromosome 10 between 57,941,104 and 59,985,708 bps had an allele frequency of 1. There were 211 mutations and 37 genes in the locus, out of which mutations in 9 genes showed non-synonymous changes. This finding is expected to contribute to future research on the identification of the causal factor differentiating C4 from C3 species that can be used

  1. Modeling of hydrogen isotopes separation in a metal hydride bed

    International Nuclear Information System (INIS)

    Charton, S.; Corriou, J.P.; Schweich, D.

    1999-01-01

    A predictive model for hydrogen isotopes separation in a non-isothermal bed of unsupported palladium hydride particles is derived. It accounts for the non-linear adsorption-dissociation equilibrium, hydrodynamic dispersion, pressure drop, mass transfer kinetics, heat of sorption and heat losses at the bed wall. Using parameters from the literature or estimated with classical correlations, the model gives simulated curves in agreement with previously published experiments without any parameter fit. The non-isothermal behavior is shown to be responsible for drastic changes of the mass transfer rate which is controlled by diffusion in the solid-phase lattice. For a feed at 300 K and atmospheric pressure, the endothermic hydride-to-deuteride exchange is kinetically controlled, whereas the reverse exothermic exchange is nearly at equilibrium. Finally, a simple and efficient thermodynamic model for the dissociative equilibrium between a metal and a diatomic gas is proposed. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. Wetting phenomena in films of molecular hydrogen isotopes

    International Nuclear Information System (INIS)

    Albrecht, U.; Conradt, R.; Herminghaus, S.; Leiderer, P.

    1996-01-01

    We have investigated various aspects of the wetting behavior of hydrogen films (including the heavier isotopes) using surface plasmon resonance, light scattering, and photoelectron emission. Studies in the vicinity of the triple point (T 3 (H 2 )=13,96 K) confirmed the known >, and gave no indications for a prewetting transition in this range. At low temperatures (T 3 /3) the equilibrium film thickness reaches only a few monolayers. Thicker films, prepared by quench-condensation of H 2 gas at 1.5 K, undergo a dewetting process during annealing: most of the film material contracts to clusters, and in between the films thins down to its equilibrium thickness. This surface diffusion process is thermally activated, with an activation energy of 23 K (in the case of H 2 ). The dewetting kinetics has not revealed any indication for a surface-molten layer on the solid films at low temperatures, or for a superfluid component

  3. Next-generation TCAP hydrogen isotope separation process

    International Nuclear Information System (INIS)

    Heung, L. K.; Sessions, H. T.; Poore, A. S.; Jacobs, W. D.; Williams, C. S.

    2008-01-01

    A thermal cycling absorption process (TCAP) for hydrogen isotope separation has been in operation at Savannah River Site since 1994. The process uses a hot/cold nitrogen system to cycle the temperature of the separation column. The hot/cold nitrogen system requires the use of large compressors, heat exchanges, valves and piping that is bulky and maintenance intensive. A new compact thermal cycling (CTC) design has recently been developed. This new design uses liquid nitrogen tubes and electric heaters to heat and cool the column directly so that the bulky hot/cold nitrogen system can be eliminated. This CTC design is simple and is easy to implement, and will be the next generation TCAP system at SRS. A twelve-meter column has been fabricated and installed in the laboratory to demonstrate its performance. The design of the system and its test results to date is discussed. (authors)

  4. Kalahari groundwaters: Their hydrogen, carbon and oxygen isotopes

    International Nuclear Information System (INIS)

    Mazor, E.; Verhagen, B.T.; Sellschop, J.P.F.; Robins, N.S.; Hutton, L.G.

    1974-01-01

    Tritium and 14 C measurements have revealed several cases of post-nuclear bomb-test rain recharge of local groundwaters, along with values indicating recharge over larger, yet hydrologically active, time scales. In general, recharge seems to follow rain distribution in being more intense in the northern rather than in the southern Kalahari. Initial δ 13 C values vary over a wide range and reveal some correlation to pH and chemical composition of the water. They cannot be used to correct for fossil carbon dilution in 14 C-age calculations. Radiocarbon-deduced ages range from recent to 30,000 years. Stable hydrogen and oxygen isotopes indicate recharge from direct rain infiltration. (author)

  5. Large scale gas chromatographic demonstration system for hydrogen isotope separation

    International Nuclear Information System (INIS)

    Cheh, C.H.

    1988-01-01

    A large scale demonstration system was designed for a throughput of 3 mol/day equimolar mixture of H,D, and T. The demonstration system was assembled and an experimental program carried out. This project was funded by Kernforschungszentrum Karlsruhe, Canadian Fusion Fuel Technology Projects and Ontario Hydro Research Division. Several major design innovations were successfully implemented in the demonstration system and are discussed in detail. Many experiments were carried out in the demonstration system to study the performance of the system to separate hydrogen isotopes at high throughput. Various temperature programming schemes were tested, heart-cutting operation was evaluated, and very large (up to 138 NL/injection) samples were separated in the system. The results of the experiments showed that the specially designed column performed well as a chromatographic column and good separation could be achieved even when a 138 NL sample was injected

  6. ICP-MS with hexapole collision cell for isotope ratio measurements of Ca, Fe, and Se

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, S.F. [Radiation Physics and Chemistry Problems Inst., Minsk (Belarus); Becker, J.S. [Central Department for Analytical Chemistry, Research Centre Juelich (Germany)

    2001-07-01

    To avoid mass interferences on analyte ions caused by argon ions and argon molecular ions via reactions with collision gases, an rf hexapole filled with helium and hydrogen has been used in inductively coupled plasma mass spectrometry (ICP-MS), and its performance has been studied. Up to tenfold improvement in sensitivity was observed for heavy elements (m > 100 u), because of better ion transmission through the hexapole ion guide. A reduction of argon ions Ar{sup +} and the molecular ions of argon ArX{sup +} (X = O, Ar) by up to three orders of magnitude was achieved in a hexapole collision cell of an ICP-MS (''Platform ICP'', Micromass, Manchester, UK) as a result of gas-phase reactions with hydrogen when the hexapole bias (HB) was set to 0 V; at an HB of 1.6 V argon, and argon-based ions of masses 40 u, 56 u, and 80 u, were reduced by approximately four, two, and five orders of magnitude, respectively. The signal-to-noise ratio {sup 80}Se/ {sup 40}Ar{sub 2}{sup +} was improved by more than five orders of magnitude under optimized experimental conditions. Dependence of mass discrimination on collision-cell properties was studied in the mass range 10 u (boron) to 238 u (uranium). Isotopic analysis of the elements affected by mass-spectrometric interference, Ca, Fe, and Se, was performed using a Meinhard nebulizer and an ultrasonic nebulizer (USN). The measured isotope ratios were comparable with tabulated values from IUPAC. Precision of 0.26%, 0.19%, and 0.12%, respectively, and accuracy of 0.13% 0.25%, and 0.92%, respectively, was achieved for isotope ratios {sup 44}Ca/ {sup 40}Ca and {sup 56}Fe/{sup 57}Fe in 10 {mu}g L{sup -1} solution nebulized by means of a USN and for {sup 78}Se/{sup 80}Se in 100 {mu}g L{sup -1} solution nebulized by means of a Meinhard nebulizer. (orig.)

  7. Carbon isotopic analysis of atmospheric methane by isotope-ratio-monitoring gas chromatography-mass spectrometry

    Science.gov (United States)

    Merritt, Dawn A.; Hayes, J. M.; Des Marais, David J.

    1995-01-01

    Less than 15 min are required for the determination of delta C(sub PDB)-13 with a precision of 0.2 ppt(1 sigma, single measurement) in 5-mL samples of air containing CH4 at natural levels (1.7 ppm). An analytical system including a sample-introduction unit incorporating a preparative gas chromatograph (GC) column for separation of CH4 from N2, O2, and Ar is described. The 15-min procedure includes time for operation of that system, high-resolution chromatographic separation of the CH4, on-line combustion and purification of the products, and isotopic calibration. Analyses of standards demonstrate that systematic errors are absent and that there is no dependence of observed values of delta on sample size. For samples containing 100 ppm or more CH4, preconcentration is not required and the analysis time is less than 5 min. The system utilizes a commercially available, high-sensitivity isotope-ratio mass spectrometer. For optimal conditions of smaple handling and combustion, performance of the system is within a factor of 2 of the shot-noise limit. The potential exists therefore for analysis of samples as small as 15 pmol CH4 with a standard deviation of less than 1 ppt.

  8. Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples.

    Science.gov (United States)

    Godin, Jean-Philippe; Breuillé, Denis; Obled, Christiane; Papet, Isabelle; Schierbeek, Henk; Hopfgartner, Gérard; Fay, Laurent-Bernard

    2008-10-01

    On-line gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is commonly used to measure isotopic ratios at natural abundance as well as for tracer studies in nutritional and medical research. However, high-precision (13)C isotopic enrichment can also be measured by liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). Indeed, LC-IRMS can be used, as shown by the new method reported here, to obtain a baseline separation and to measure (13)C isotopic enrichment of underivatised amino acids (Asp, Thr-Ser, Glu, Pro, Gly, Ala, Cys and Val). In case of Val, at natural abundance, the SD(delta(13)C) reported with this method was found to be below 1 per thousand . Another key feature of the new LC-IRMS method reported in this paper is the comparison of the LC-IRMS approach with the conventional GC-C-IRMS determination. To perform this comparative study, isotopic enrichments were measured from underivatised Val and its N(O, S)-ethoxycarbonyl ethyl ester derivative. Between 0.0 and 1.0 molar percent excess (MPE) (delta(13)C= -12.3 to 150.8 per thousand), the calculated root-mean-square (rms) of SD was 0.38 and 0.46 per thousand and the calculated rms of accuracy was 0.023 and 0.005 MPE, respectively, for GC-C-IRMS and LC-IRMS. Both systems measured accurately low isotopic enrichments (0.002 atom percent excess (APE)) with an SD (APE) of 0.0004. To correlate the relative (delta(13)C) and absolute (atom%, APE and MPE) isotopic enrichment of Val measured by the GC-C-IRMS and LC-IRMS devices, mathematical equations showing the slope and intercept of the curves were established and validated with experimental data between 0.0 to 2.3 MPE. Finally, both GC-C-IRMS and LC-IRMS instruments were also used to assess isotopic enrichment of protein-bound (13)C-Val in tibial epiphysis in a tracer study performed in rats. Isotopic enrichments measured by LC-IRMS and GC-C-IRMS were not statistically different (p>0.05). The results of this work indicate that

  9. Investigation of the anomalous isotope ratios of the Central-Transdanubian bauxites

    International Nuclear Information System (INIS)

    Viczian, M.

    1977-01-01

    In the case of the Central Transdanubian bauxite deposits significant anomaly of the lead isotope ratios has been found. The 206 Pb/ 204 Pb isotope ratio in approximately 40 samples was investigated and the results have shown an average deviation from the literary value by about 80%. These results have been cont confirmed by thermal ionisation measurings, too. Some possibilities for the explanation of this isotope anomaly are also dealt with in the paper. (author)

  10. Round robin analyses of hydrogen isotope thin films standards

    Energy Technology Data Exchange (ETDEWEB)

    Banks, J.C. E-mail: jcbanks@sandia.gov; Browning, J.F.; Wampler, W.R.; Doyle, B.L.; LaDuca, C.A.; Tesmer, J.R.; Wetteland, C.J.; Wang, Y.Q

    2004-06-01

    Hydrogen isotope thin film standards have been manufactured at Sandia National Laboratories for use by the materials characterization community. Several considerations were taken into account during the manufacture of the ErHD standards, with accuracy and stability being the most important. The standards were fabricated by e-beam deposition of Er onto a Mo substrate and the film stoichiometrically loaded with hydrogen and deuterium. To determine the loading accuracy of the standards two random samples were measured by thermal desorption mass spectrometry and atomic absorption spectrometry techniques with a stated combined accuracy of {approx}1.6% (1{sigma}). All the standards were then measured by high energy RBS/ERD and RBS/NRA with the accuracy of the techniques {approx}5% (1{sigma}). The standards were then distributed to the IBA materials characterization community for analysis. This paper will discuss the suitability of the standards for use by the IBA community and compare measurement results to highlight the accuracy of the techniques used.

  11. Palladium alloy membrane process for the treatment of hydrogen isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hongsuk; Paek, Seungwoo; Lee, Minsoo; Kim, Kwangrag; Yim, Sungpaal; Ahn, Dohee [KAERI, Daejeon (Korea, Republic of); Shim, Myunghwa [Univ. of Science and Technology, Daejeon (Korea, Republic of)

    2005-11-15

    Tritium is a radioactive isotope of hydrogen and it has a half-life of 12.3 years; it decays to He-3 by emitting a low energy beta radiation with an average energy of 5.7 keV and a maximum energy of 18.6 keV. Transfer of environmentally tritiated water to humans takes place via an inhalation, diffusion through the skin and ingestion. Radioactive waste containing tritium is continuously generated by the nuclear industry in, for example, nuclear reactor operations and a radioisotope production, as well as in medical research. Methods for removing tritium from liquid waste provide an alternative to the control of tritium emissions and a personnel exposure. A combined electrolysis and catalytic exchange process is a very effective method to remove small quantities of tritium from light or heavy waste water streams. The process consists of three main steps: (a) A front end step that exchanges the tritium to a less toxic hydrogen phase. This can be performed either through a chemical exchange in the presence of a platinum supported catalyst or through the decomposition of water. (b) A back end process that purifies the tritiated hydrogen gas which evolved from the electrolysis. This can be performed through a palladium alloy membrane separator. (c) A means of storing the concentrated gas safely. Uranium is used if the storage is temporary; titanium is usually employed for long term storage. To gain a better understanding of the tritiated hydrogen gas purification process, a mathematical model of the palladium alloy membrane has been used. This model is described herein, and the representative results of the model calculations are presented. The authors selected the palladium alloy membrane for the hydrogen purification process by considering the membrane properties, such as a chemical resistance, mechanical stability, thermal stability, high permeability, and a stable operation. The solution-diffusion model can be a useful tool for designing a membrane permeator. The

  12. Release of hydrogen isotopes from carbon based fusion reactor materials

    International Nuclear Information System (INIS)

    Vainonen-Ahlgren, E.

    2000-01-01

    The purpose of this study is to understand the annealing behavior of hydrogen isotopes in carbon based materials. Also, the density of the material and structural changes after thermal treatment and ion irradiation are examined. The study of hydrogen diffusion in diamondlike carbon films revealed an activation energy of 2.0 eV, while the deuterium diffusion, due to better measuring sensitivity, is found to be concentration dependent with the effective diffusion coefficient becoming smaller with decreasing deuterium concentration. To explain the experimentally observed profiles, a model according to which atomic deuterium diffuses and deuterium in clusters is immobile is developed. The concentration of immobile D was assumed to be an analytical function of the total D concentration. To describe the annealing behavior of D incorporated in diamondlike carbon films during the deposition process, a model taking into account diffusion of free D and thermal detrapping and trapping of D was developed. The difference in the analysis explains the disagreement of activation energy (1.5 ± 0.2 eV) with the value of 2,9± 0.1 eV obtained for D implanted samples earlier. The same model was applied to describe the experimental profiles in Si doped diamondlike carbon films. Si affects the retention of D in diamondlike carbon films. The amount of D depends on Si content in the co-deposited but not implanted samples. Besides, Si incorporation into carbon coating decreases to some extent the graphitization of the films and leads to formation of a structure which is stable under thermal treatment and ion irradiation. Hydrogen migration in the hydrogen and methane co-deposited films was also studied. In samples produced in methane atmosphere and annealed at different temperatures, the hydrogen concentration level decreases in the bulk, with more pronounced release at the surface region. In the case of coatings deposited by a methane ion beam, the H level also decreases with increasing

  13. Palladium alloy membrane process for the treatment of hydrogen isotopes

    International Nuclear Information System (INIS)

    Chung, Hongsuk; Paek, Seungwoo; Lee, Minsoo; Kim, Kwangrag; Yim, Sungpaal; Ahn, Dohee; Shim, Myunghwa

    2005-01-01

    Tritium is a radioactive isotope of hydrogen and it has a half-life of 12.3 years; it decays to He-3 by emitting a low energy beta radiation with an average energy of 5.7 keV and a maximum energy of 18.6 keV. Transfer of environmentally tritiated water to humans takes place via an inhalation, diffusion through the skin and ingestion. Radioactive waste containing tritium is continuously generated by the nuclear industry in, for example, nuclear reactor operations and a radioisotope production, as well as in medical research. Methods for removing tritium from liquid waste provide an alternative to the control of tritium emissions and a personnel exposure. A combined electrolysis and catalytic exchange process is a very effective method to remove small quantities of tritium from light or heavy waste water streams. The process consists of three main steps: (a) A front end step that exchanges the tritium to a less toxic hydrogen phase. This can be performed either through a chemical exchange in the presence of a platinum supported catalyst or through the decomposition of water. (b) A back end process that purifies the tritiated hydrogen gas which evolved from the electrolysis. This can be performed through a palladium alloy membrane separator. (c) A means of storing the concentrated gas safely. Uranium is used if the storage is temporary; titanium is usually employed for long term storage. To gain a better understanding of the tritiated hydrogen gas purification process, a mathematical model of the palladium alloy membrane has been used. This model is described herein, and the representative results of the model calculations are presented. The authors selected the palladium alloy membrane for the hydrogen purification process by considering the membrane properties, such as a chemical resistance, mechanical stability, thermal stability, high permeability, and a stable operation. The solution-diffusion model can be a useful tool for designing a membrane permeator. The

  14. On the Development of Hydrogen Isotope Extraction Technologies for a Full LiMIT-Style PFC Liquid Lithium Loop

    Science.gov (United States)

    Christenson, Michael; Szott, Matthew; Stemmley, Steven; Mettler, Jeremy; Wendeborn, John; Moynihan, Cody; Ahn, Chisung; Andruczyk, Daniel; Ruzic, David

    2017-10-01

    Lithium has proven over numerous studies to improve core confinement, allowing access to operational regimes previously unattainable when using solid, high-Z divertor and limiter modules in magnetic confinement devices. Lithium readily absorbs fuel species, and while this is advantageous, it is also detrimental with regards to tritium inventory and safety concerns. As such, extraction technologies for the recovery of hydrogenic isotopes captured by lithium require development and testing in the context of a larger lithium loop recycling system. Proposed reclamation technologies at the University of Illinois at Urbana-Champaign (UIUC) will take advantage of the thermophysical properties of the lithium-hydrogen-lithium hydride system as the driving force for recovery. Previous work done at UIUC indicates that hydrogen release from pure lithium hydride reaches a maximum of 7 x 1018 s-1 at 665 °C. While this recovery rate is appreciable, reactor-scale scenarios will require isotope recycling to happen on an even faster timescale. The ratio of isotope dissolution to hydride precipitate formation must therefore be determined, along with the energy needed to recoup trapped hydrogen isotopes. Extraction technologies for use with a LiMIT-style loop system will be discussed and results will be presented. DOE/ALPS DE-FG02-99ER54515.

  15. A Microdrop Generator for the Calibration of a Water Vapor Isotope Ratio Spectrometer

    NARCIS (Netherlands)

    Iannone, Rosario Q.; Romanini, Daniele; Kassi, Samir; Meijer, Harro A. J.; Kerstel, Erik R. Th.

    A microdrop generator is described that produces water vapor with a known isotopic composition and volume mixing ratio for the calibration of a near-infrared diode laser water isotope ratio spectrometer. The spectrometer is designed to measure in situ the water vapor deuterium and oxygen ((17)O and

  16. Lead isotope ratios of galenas from the Hida area

    International Nuclear Information System (INIS)

    Sato, Kazuo; Sasaki, Akira; Akiyama, Shin-ichi; Konagai, Kenji.

    1978-01-01

    Ore lead isotope data of the Kamioka and nearby lead-zinc mineralizations in the Hida metamorphic terrain are variable. Small but distinct isotopic variation is observed even in a single ore deposit. The present site of the Hida metamorphic terrain once was occupied by a Precambrian continent. The leads from the metamorphic, plutonic and sedimentary rocks indicate such continental nature of this terrain, as they have more complex isotopic patterns than those observed in the leads from igneous rocks and ores in younger terrains in Japan. The variability of ore lead isotopes in the Hida area could also be related to the presence of the old basement structure, implying that the leads in the Kamioka and nearby ore deposits came from more than a source of material. (mori, K.)

  17. Forensic Applications of Light-Element Stable Isotope Ratios of Ricinus communis Seeds and Ricin Preparations

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, Helen W.; West, Jason B.; Ehleringer, James

    2013-01-01

    Seeds of the castor plant Ricinus communis, also known as castor beans, are of forensic interest because they are the source of the poison ricin. We have tested whether stable isotope ratios of castor seeds and ricin prepared by various methods can be used as a forensic signature. We collected over 300 castor seed samples from locations around the world and measured the C, N, O, and H stable isotope ratios of the whole seeds, oil, and three types of ricin preparations. Our results demonstrate that N isotope ratios can be used to correlate ricin prepared by any of these methods to source seeds. Further, stable isotope ratios distinguished >99% of crude and purified ricin protein samples in pair-wise comparison tests. Stable isotope ratios therefore constitute a valuable forensic signature for ricin preparations.

  18. Stable isotope ratio determination of the origin of vanillin in vanilla extracts and its relationship to vanillin/potassium ratios

    International Nuclear Information System (INIS)

    Martin, G.E.; Alfonso, F.C.; Figert, D.M.; Burggraff, J.M.

    1981-01-01

    A method is described for isolating vanillin from vanilla extract, followed by stable isotope ratio analysis to determine the amount of natural vanillin contained in adulterated vanilla extracts. After the potassium content is determined, the percent Madagascar and/or Java vanilla beans incorporated into the extract may then be approximated from the vanillin/potassium ratio

  19. Determination of boron isotope ratios by high-resolution continuum source molecular absorption spectrometry using graphite furnace vaporizers

    Science.gov (United States)

    Abad, Carlos; Florek, Stefan; Becker-Ross, Helmut; Huang, Mao-Dong; Heinrich, Hans-Joachim; Recknagel, Sebastian; Vogl, Jochen; Jakubowski, Norbert; Panne, Ulrich

    2017-10-01

    Boron isotope amount ratios n(10B)/n(11B) have been determined by monitoring the absorption spectrum of boron monohydride (BH) in a graphite furnace using high-resolution continuum source molecular absorption spectrometry (HR-CS-MAS). Bands (0 → 0) and (1 → 1) for the electronic transition X1Σ+ → A1Π were evaluated around wavelengths 433.1 nm and 437.1 nm respectively. Clean and free of memory effect molecular spectra of BH were recorded. In order to eliminate the memory effect of boron, a combination of 2% (v/v) hydrogen gas in argon and 1% trifluoromethane in argon, an acid solution of calcium chloride and mannitol as chemical modifiers was used. Partial least square regression (PLS) for analysis of samples and reference materials were applied. For this, a spectral library with different isotopes ratios for PLS regression was built. Results obtained around the 433.1 nm and 437.1 nm spectral regions are metrologically compatible with those reported by mass spectrometric methods. Moreover, for the evaluated region of 437 nm, an accuracy of 0.15‰ is obtained as the average deviation from the isotope reference materials. Expanded uncertainties with a coverage factor of k = 2 range between 0.15 and 0.44‰. This accuracy and precision are compatible with those obtained by mass spectrometry for boron isotope ratio measurements.

  20. Study of hydrogen isotopes super permeation through vanadium membrane on 'Prometheus' setup

    International Nuclear Information System (INIS)

    Musyaev, R. K.; Yukhimchuk, A. A.; Lebedev, B. S.; Busnyuk, A. O.; Notkin, M. E.; Samartsev, A. A.; Livshits, A. I.

    2008-01-01

    To develop the membrane pumping technology by means of superpermeable membranes at RFNC-VNIIEF in the 'Prometheus' setup, the experiments on superpermeation of hydrogen isotopes through metal membranes were carried out. The experimental results on superpermeation of thermal atoms of hydrogen isotopes including tritium through a cylindrical vanadium membrane are presented. The possibility of effective pumping, compression and recuperation of hydrogen isotopes by means of superpermeable membrane was demonstrated. The evaluation of membrane pumping rates and asymmetry degree of pure vanadium membrane was given. The work was performed under the ISTC-2854 project. (authors)

  1. Parameter study on Japanese proposal of ITER hydrogen isotope separation system

    International Nuclear Information System (INIS)

    Yoshida, Hiroshi; Enoeda, Mikio; Tanaka, Shigeru; Ohokawa, Yoshinao; Ohara, Atsushi; Nagakura, Masaaki; Naito, Taisei; Nagashima, Kazuhiro.

    1991-01-01

    As part of Japanese design contribution in the ITER activity, conceptual design of an entire ITER tritium system and their safety analysis have been carried out through the three-year period since 1988. The tritium system includes the following subsystems; - Fuelling (gas puffing and pellet injection) subsystem, - Torus vacuum pumping subsystem, - Plasma exhaust gas purification subsystem, - Hydrogen isotope separation subsystem, - NBI gas processing subsystem, - Blanket tritium recovery subsystem, - Tritiated water processing subsystem, - Tritium safety subsystem. Hydrogen isotope separation system is a key subsystem in the ITER tritium system because it is connected to all above subsystems. This report describes an analytical study on the Japanese concept of hydrogen isotope separation system. (author)

  2. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates.

    Science.gov (United States)

    Moerdijk-Poortvliet, Tanja C W; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J; Boschker, Henricus T S

    2015-07-15

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although LC/IRMS is expected to be more accurate and precise, no direct comparison has been reported. GC/IRMS with the aldonitrile penta-acetate (ANPA) derivatisation method was compared with LC/IRMS without derivatisation. A large number of glucose standards and a variety of natural samples were analysed for five neutral carbohydrates at natural abundance as well as at (13)C-enriched levels. Gas chromatography/chemical ionisation mass spectrometry (GC/CIMS) was applied to check for incomplete derivatisation of the carbohydrate, which would impair the accuracy of the GC/IRMS method. The LC/IRMS technique provided excellent precision (±0.08‰ and ±3.1‰ at natural abundance and enrichment levels, respectively) for the glucose standards and this technique proved to be superior to GC/IRMS (±0.62‰ and ±19.8‰ at natural abundance and enrichment levels, respectively). For GC/IRMS measurements the derivatisation correction and the conversion of carbohydrates into CO2 had a considerable effect on the measured δ(13)C values. However, we did not find any significant differences in the accuracy of the two techniques over the full range of natural δ(13)C abundances and (13)C-labelled glucose. The difference in the performance of GC/IRMS and LC/IRMS diminished when the δ(13)C values were measured in natural samples, because the chromatographic performance and background correction became critical factors, particularly for LC/IRMS. The derivatisation of carbohydrates for the GC/IRMS method was complete. Although both LC/IRMS and GC/IRMS are reliable techniques for compound-specific stable carbon isotope analysis of carbohydrates (provided that derivatisation is complete and the

  3. Decade to centennial resolution hydrogen isotopic record of climate change from southern New England for the past 16 kyr: proxy validation and multi-proxy comparisons

    Science.gov (United States)

    Huang, Y.; Gao, L.; Hou, J.; Shuman, B. N.; Oswald, W.; Foster, D.

    2009-12-01

    Open system lakes in New England offer excellent archives of precipitation isotopic ratios that yield quantitative paleoclimate information. We have demonstrated previously from a lake sediment transect that hydrogen isotopic ratios of a middle-chain length fatty acid, behenic acid (BA), faithfully record precipitation isotopic ratios. We hypothesized that mid-chain n-alkyl lipids in these small lakes were primarily derived from aquatic plants that record lake water isotopic ratios. To test this hypothesis, we conducted systematic and extensive sampling of both terrestrial and aquatic plants over the past two years at two typical kettle hole lakes, Blood Pond and Rocky Pond, MA, and used a linear algebra approach to delineate percentage inputs of aquatic and terrestrial plant contributions to mid-chain n-alkyl lipids. Our results demonstrate that >92 % of the mid-chain n-alkyl lipids is derived from submerged and floating aquatic macrophytes. Our new data provide a solid basis for the application of behenic hydrogen isotopic ratios as a paleoclimate proxy from small lakes. We will present a decadal to centennial scale 16 kyr record of BA hydrogen isotopic ratios from Blood Pond, and will discuss the results in light of published pollen and lake level data. Overall, our hydrogen isotopic record is fully consistent with regional climate scenarios, including the distinctive warming at B-A events, abrupt cooling at YD event, and transition from glacial to Holcoene climate conditions. However, our high-solution isotopic data provides important new insights concerning abrupt regional climate variability. We demonstrate that the New England climate is exceptionally senstive to AMOC changes and solar forcing and that many of the abrupt climate fluctuations exert major impacts on terrestrial ecosystems, hydrology and lake levels.

  4. Broadband non-selective excitation of plutonium isotopes for isotope ratio measurements in resonance ionization mass spectrometry: a theoretical study.

    Science.gov (United States)

    Sankari, M

    2012-10-15

    Making isotope ratio measurements with minimum isotope bias has always been a challenging task to mass spectrometrists, especially for the specific case of plutonium, owing to the strategic importance of the element. In order to use resonance ionization mass spectrometry (RIMS) as a tool for isotope ratio measurements, optimization of the various laser parameters and other atomic and system parameters is critical to minimize isotopic biases. Broadband simultaneous non-selective excitation of the isotopes of plutonium in the triple resonance excitation scheme with λ(1) = 420.77 nm, λ(2) = 847.28 nm, and λ(3) = 767.53 nm based on density matrix formalism has been theoretically computed for the determination of isotope ratios. The effects of the various laser parameters and other factors such as the atomization temperature and the dimensions of the atomic beam on the estimation of isotope ratios were studied. The effects of Doppler broadening, and time-dependent excitation parameters such as Rabi frequencies, ionization rate and the effect of non-Lorenztian lineshape have all been incorporated. The average laser powers and bandwidths for the three-excitation steps were evaluated for non-selective excitation. The laser intensity required to saturate the three-excitation steps were studied. The two-dimensional lineshape contour and its features were investigated, while the reversal of peak asymmetry of two-step and two-photon excitation peaks under these conditions is discussed. Optimized powers for the non-selective ionization of the three transitions were calculated as 545 mW, 150 mW and 545 mW and the laser bandwidth for all the three steps was ~20 GHz. The isotopic bias between the resonant and off-resonant isotope under the optimized conditions was no more than 9%, which is better than an earlier reported value. These optimized laser power and bandwidth conditions are better than in the earlier experimental work since these comprehensive calculations yield

  5. Application of hydrogen isotopes and metal hydrides in future energy source

    Energy Technology Data Exchange (ETDEWEB)

    Guoqiang, Jiang [Sichuan Inst. of Materials and Technology, Chengdu, SC (China)

    1994-12-01

    The probable application of hydrogen isotopes and metal hydrides to future energy source is reviewed. Starting from existing state of China`s energy source, the importance for developing hydrogen energy and fusion energy is explained. It is suggested that the application investigation of hydrogen energy and hydrogen storage materials should be spurred and encouraged; keeping track of the development on tritium technology for fusion reactor is stressed.

  6. Application of hydrogen isotopes and metal hydrides in future energy source

    International Nuclear Information System (INIS)

    Jiang Guoqiang

    1994-12-01

    The probable application of hydrogen isotopes and metal hydrides to future energy source is reviewed. Starting from existing state of China's energy source, the importance for developing hydrogen energy and fusion energy is explained. It is suggested that the application investigation of hydrogen energy and hydrogen storage materials should be spurred and encouraged; keeping track of the development on tritium technology for fusion reactor is stressed

  7. Site-Specific Hydrogen Isotope Composition of Propane: Mass spectrometric methods, equilibrium temperature dependence, and kinetics of exchange

    Science.gov (United States)

    Xie, H.; Ponton, C.; Kitchen, N.; Lloyd, M. K.; Lawson, M.; Formolo, M. J.; Eiler, J. M.

    2016-12-01

    Intramolecular isotope ordering can constrain temperatures of synthesis, mechanisms of formation, and/or source substrates of organic compounds. Here we explore site-specific hydrogen isotope variations of propane. Statistical thermodynamic models predict that at equilibrium methylene hydrogen (-CH2-) in propane will be 10's of per mil higher in D/H ratio than methyl hydrogen (-CH3) at geologically relevant temperatures, and that this difference is highly temperature dependent ( 0.5-1 ‰/°C). Chemical-kinetic controls on site-specific D/H in propane could constrain the mechanisms, conditions and extents of propane synthesis or destruction. We have developed a method for measuring the difference in D/H ratio between methylene and methyl hydrogen in propane by gas source mass spectrometry. The data were measured using the Thermo Fisher Double Focusing Sector high resolution mass spectrometer (DFS), and involve comparison of the D/H ratios of molecular ion (C3H8+) and the ethyl fragmental ion (C2H5+). We demonstrate the accuracy and precision of this method through analysis of D-labeled and independently analyzed propanes. In the exchange experiments, propane was heated (100-200 oC) either alone or in the presence of D-enriched water (δD=1,1419 ‰ SMOW), with or without one of several potentially catalytic substrates for hours to weeks. Propane was found to exchange hydrogen with water vigorously at 200 °C in the presence of metal catalysts. In the presence of Ni catalyst, methylene hydrogen exchanges 2.5 times faster than methyl hydrogen. Hydrogen exchange in the presence of Pd catalyst is more effective and can equilibrate hydrogen isotope distribution on propane on the order of 7 days. Isotopic exchange in the presence of natural materials have also been tested, but is only measurable in the methylene group at 200 °C. High catalytic activity of Pd permits attainment of a bracketed, time-invariant equilibrium state that we use to calibrate the site

  8. Platinum stable isotope ratio measurements by double-spike multiple collector ICPMS

    DEFF Research Database (Denmark)

    Creech, John; Baker, Joel; Handler, Monica

    2013-01-01

    We present a new technique for the precise determination of platinum (Pt) stable isotope ratios by multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS) using two different Pt double-spikes ( Pt-Pt and Pt-Pt). Results are expressed relative to the IRMM-010 Pt isotope standard......) can be obtained on Pt stable isotope ratios with either double-spike. Elemental doping tests reveal that double-spike corrected Pt stable isotope ratios are insensitive to the presence of relatively high (up to 10%) levels of matrix elements, although the Pt-Pt double-spike is affected by an isobaric...... = 7.308%) results in a redefined Pt atomic weight of 195.08395 ± 0.00068. Using our technique we have measured small, reproducible and statistically significant offsets in Pt stable isotope ratios between different Pt element standards and the IRMM-010 standard, which potentially indicates...

  9. Simultaneous stable carbon isotopic analysis of wine glycerol and ethanol by liquid chromatography coupled to isotope ratio mass spectrometry.

    Science.gov (United States)

    Cabañero, Ana I; Recio, Jose L; Rupérez, Mercedes

    2010-01-27

    A novel procedure was established for the simultaneous characterization of wine glycerol and ethanol (13)C/(12)C isotope ratio, using liquid chromatography/isotope ratio mass spectrometry (LC-IRMS). Several parameters influencing separation of glycerol and ethanol from wine matrix were optimized. Results obtained for 35 Spanish samples exposed no significant differences and very strong correlations (r = 0.99) between the glycerol (13)C/(12)C ratios obtained by an alternative method (gas chromatography/isotope ratio mass spectrometry) and the proposed new methodology, and between the ethanol (13)C/(12)C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The accuracy of the proposed method varied from 0.01 to 0.19 per thousand, and the analytical precision was better than 0.25 per thousand. The new developed LC-IRMS method it is the first isotopic method that allows (13)C/(12)C determination of both analytes in the same run directly from a liquid sample with no previous glycerol or ethanol isolation, overcoming technical difficulties associated with complex sample treatment and improving in terms of simplicity and speed.

  10. Oxygen and hydrogen isotope fractionation during cellulose metabolism in Lemna gibba L

    International Nuclear Information System (INIS)

    Yakir, D.; DeNiro, M.J.

    1990-01-01

    Lemna gibba L. B3 was grown under heterotrophic, photoheterotrophic, and autotrophic conditions in water having a variety of hydrogen and oxygen isotopic compositions. The slopes of the linear regression lines between the isotopic composition of water and leaf cellulose indicated that under the three growth conditions about 40, 70, and 100% of oxygens and carbon-bound hydrogens of cellulose exchanged with those of water prior to cellulose formation. Using the equations of the linear relationships, we estimated the overall fractionation factors between water and the exchanged oxygen and carbon bound-hydrogen of cellulose. At least two very different isotope effects must determine the hydrogen isotopic composition of Lemna cellulose. One reflects the photosynthetic reduction of NADP, while the second reflects exchange reactions that occur subsequent to NADP reduction. Oxygen isotopic composition of cellulose apparently is determined by a single type of exchange reaction with water. Under different growth conditions, variations in metabolic fluxes affect the hydrogen isotopic composition of cellulose by influencing the extent to which the two isotope effects mentioned above are recorded. The oxygen isotopic composition of cellulose is not affected by such changes in growth conditions

  11. Hydrogen-isotope motion in scandium studied by ultrasonic measurements

    International Nuclear Information System (INIS)

    Leisure, R.G.; Schwarz, R.B.; Migliori, A.; Torgeson, D.R.; Svare, I.

    1993-01-01

    Resonant ultrasound spectroscopy has been used to investigate ultrasonic attenuation in single crystals of Sc, ScH 0.25 , and ScD 0.18 over the temperature range of 10--300 K for frequencies near 1 MHz. Ultrasonic-attenuation peaks were observed in the samples containing H or D with the maximum attenuation occurring near 25 K for ScH 0.25 and near 50 K for ScD 0.18 . The general features of the data suggest that the motion reflected in the ultrasonic attenuation is closely related to the low-temperature motion seen in nulcear-magnetic-resonance spin-lattice-relaxation measurements. The ultrasonic results were fit with a two-level-system (TLS) model involving tunneling between highly asymmetric sites. The relaxation of the TLS was found to consist of two parts: a weakly temperature-dependent part, probably due to coupling to electrons; and a much more strongly temperature-dependent part, attributed to multiple-phonon processes. The strongly temperature-dependent part was almost two orders of magnitude faster in ScH 0.25 than in ScD 0.18 , in accordance with the idea that tunneling is involved in the motion. Surprisingly, the weakly temperature-dependent part was found to be about the same for the two isotopes. The asymmetries primarily responsible for coupling the TLS to the ultrasound are attributed to interactions between hydrogen ions that lie on adjacent c axes. The results are consistent with an isotope-independent strength for the coupling of the TLS to the ultrasound

  12. Optimal sample to tracer ratio for isotope dilution mass spectrometry: the polyisotopic case

    International Nuclear Information System (INIS)

    Laszlo, G.; Ridder, P. de; Goldman, A.; Cappis, J.; Bievre, P. de

    1991-01-01

    The Isotope Dilution Mass Spectrometry (IDMS) measurement technique provides a means for determining the unknown amount of various isotopes of an element in a sample solution of known mass. The sample solution is mixed with an auxiliary solution, or tracer, containing a known amount of the same element having the same isotopes but of different relative abundances or isotopic composition and the induced change in the isotopic composition measured by isotope mass spectrometry. The technique involves the measurement of the abundance ratio of each isotope to a (same) reference isotope in the sample solution, in the tracer solution and in the blend of the sample and tracer solution. These isotope ratio measurements, the known element amount in the tracer and the known mass of sample solution are used to calculate the unknown amount of one isotope in the sample solution. Subsequently the unknown amount of element is determined. The purpose of this paper is to examine the optimization of the ratio of the estimated unknown amount of element in the sample solution to the known amount of element in the tracer solution in order to minimize the relative uncertainty in the determination of the unknown amount of element

  13. Non-chondritic iron isotope ratios in planetary mantles as a result of core formation

    Science.gov (United States)

    Elardo, Stephen M.; Shahar, Anat

    2017-02-01

    Information about the materials and conditions involved in planetary formation and differentiation in the early Solar System is recorded in iron isotope ratios. Samples from Earth, the Moon, Mars and the asteroid Vesta reveal significant variations in iron isotope ratios, but the sources of these variations remain uncertain. Here we present experiments that demonstrate that under the conditions of planetary core formation expected for the Moon, Mars and Vesta, iron isotopes fractionate between metal and silicate due to the presence of nickel, and enrich the bodies' mantles in isotopically light iron. However, the effect of nickel diminishes at higher temperatures: under conditions expected for Earth's core formation, we infer little fractionation of iron isotopes. From our experimental results and existing conceptual models of magma ocean crystallization and mantle partial melting, we find that nickel-induced fractionation can explain iron isotope variability found in planetary samples without invoking nebular or accretionary processes. We suggest that near-chondritic iron isotope ratios of basalts from Mars and Vesta, as well as the most primitive lunar basalts, were achieved by melting of isotopically light mantles, whereas the heavy iron isotope ratios of terrestrial ocean floor basalts are the result of melting of near-chondritic Earth mantle.

  14. Impact of metabolism and growth phase on the hydrogen isotopic composition of microbial fatty acids

    Science.gov (United States)

    Heinzelmann, Sandra M.; Villanueva, Laura; Sinke-Schoen, Danielle; Sinninghe Damsté, Jaap S.; Schouten, Stefan; van der Meer, Marcel T. J.

    2015-01-01

    Microorganisms are involved in all elemental cycles and therefore it is important to study their metabolism in the natural environment. A recent technique to investigate this is the hydrogen isotopic composition of microbial fatty acids, i.e., heterotrophic microorganisms produce fatty acids enriched in deuterium (D) while photoautotrophic and chemoautotrophic microorganisms produce fatty acids depleted in D compared to the water in the culture medium (growth water). However, the impact of factors other than metabolism have not been investigated. Here, we evaluate the impact of growth phase compared to metabolism on the hydrogen isotopic composition of fatty acids of different environmentally relevant microorganisms with heterotrophic, photoautotrophic and chemoautotrophic metabolisms. Fatty acids produced by heterotrophs are enriched in D compared to growth water with εlipid/water between 82 and 359‰ when grown on glucose or acetate, respectively. Photoautotrophs (εlipid/water between −149 and −264‰) and chemoautotrophs (εlipid/water between −217 and −275‰) produce fatty acids depleted in D. Fatty acids become, in general, enriched by between 4 and 46‰ with growth phase which is minor compared to the influence of metabolisms. Therefore, the D/H ratio of fatty acids is a promising tool to investigate community metabolisms in nature. PMID:26005437

  15. Online stable carbon isotope ratio measurement in formic acid, acetic acid, methanol and ethanol in water by high performance liquid chromatography-isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    Tagami, Keiko; Uchida, Shigeo

    2008-01-01

    A suitable analysis condition was determined for high performance liquid chromatography-isotope ratio mass spectrometry (HPLC-IRMS) while making sequential measurements of stable carbon isotope ratios of δ 13 C in formic acid, acetic acid, methanol and ethanol dissolved in water. For this online column separation method, organic reagents are not applicable due to carbon contamination; thus, water and KH 2 PO 4 at low concentrations were tested as mobile phase in combination with a HyPURITY AQUASTAR TM column. Formic acid, acetic acid, methanol and ethanol were separated when 2 mM KH 2 PO 4 aqueous solution was used. Under the determined analysis condition for HPLC-IRMS, carbon concentrations could be measured quantitatively as well as carbon isotope ratio when carbon concentration was higher than 0.4 mM L for each chemical

  16. 196Hg and 202Hg isotopic ratios in chondrites: revisited

    International Nuclear Information System (INIS)

    Jovanovic, S.; Reed, G.W. Jr.

    1976-01-01

    Additional evidence for an isotopically anomalous Hg fraction in unequilibrated meteorites has been obtained using neutron activation to produce 196 Hg and 202 Hg followed by stepwise heating to extract the Hg. In the latest experiments Allende matrix samples released the anomalous Hg but various high-temperature inclusions did not. Nucleogenetic processes are suggested as the probable cause of the anomaly. (Auth.)

  17. Chlorine isotope effects from isotope ratio mass spectrometry suggest intramolecular C-Cl bond competition in trichloroethene (TCE) reductive dehalogenation.

    Science.gov (United States)

    Cretnik, Stefan; Bernstein, Anat; Shouakar-Stash, Orfan; Löffler, Frank; Elsner, Martin

    2014-05-20

    Chlorinated ethenes are prevalent groundwater contaminants. To better constrain (bio)chemical reaction mechanisms of reductive dechlorination, the position-specificity of reductive trichloroethene (TCE) dehalogenation was investigated. Selective biotransformation reactions (i) of tetrachloroethene (PCE) to TCE in cultures of Desulfitobacterium sp. strain Viet1; and (ii) of TCE to cis-1,2-dichloroethene (cis-DCE) in cultures of Geobacter lovleyi strain SZ were investigated. Compound-average carbon isotope effects were -19.0‰ ± 0.9‰ (PCE) and -12.2‰ ± 1.0‰ (TCE) (95% confidence intervals). Using instrumental advances in chlorine isotope analysis by continuous flow isotope ratio mass spectrometry, compound-average chorine isotope effects were measured for PCE (-5.0‰ ± 0.1‰) and TCE (-3.6‰ ± 0.2‰). In addition, position-specific kinetic chlorine isotope effects were determined from fits of reactant and product isotope ratios. In PCE biodegradation, primary chlorine isotope effects were substantially larger (by -16.3‰ ± 1.4‰ (standard error)) than secondary. In TCE biodegradation, in contrast, the product cis-DCE reflected an average isotope effect of -2.4‰ ± 0.3‰ and the product chloride an isotope effect of -6.5‰ ± 2.5‰, in the original positions of TCE from which the products were formed (95% confidence intervals). A greater difference would be expected for a position-specific reaction (chloride would exclusively reflect a primary isotope effect). These results therefore suggest that both vicinal chlorine substituents of TCE were reactive (intramolecular competition). This finding puts new constraints on mechanistic scenarios and favours either nucleophilic addition by Co(I) or single electron transfer as reductive dehalogenation mechanisms.

  18. Chlorine Isotope Effects from Isotope Ratio Mass Spectrometry Suggest Intramolecular C-Cl Bond Competition in Trichloroethene (TCE Reductive Dehalogenation

    Directory of Open Access Journals (Sweden)

    Stefan Cretnik

    2014-05-01

    Full Text Available Chlorinated ethenes are prevalent groundwater contaminants. To better constrain (biochemical reaction mechanisms of reductive dechlorination, the position-specificity of reductive trichloroethene (TCE dehalogenation was investigated. Selective biotransformation reactions (i of tetrachloroethene (PCE to TCE in cultures of Desulfitobacterium sp. strain Viet1; and (ii of TCE to cis-1,2-dichloroethene (cis-DCE in cultures of Geobacter lovleyi strain SZ were investigated. Compound-average carbon isotope effects were −19.0‰ ± 0.9‰ (PCE and −12.2‰ ± 1.0‰ (TCE (95% confidence intervals. Using instrumental advances in chlorine isotope analysis by continuous flow isotope ratio mass spectrometry, compound-average chorine isotope effects were measured for PCE (−5.0‰ ± 0.1‰ and TCE (−3.6‰ ± 0.2‰. In addition, position-specific kinetic chlorine isotope effects were determined from fits of reactant and product isotope ratios. In PCE biodegradation, primary chlorine isotope effects were substantially larger (by −16.3‰ ± 1.4‰ (standard error than secondary. In TCE biodegradation, in contrast, the product cis-DCE reflected an average isotope effect of −2.4‰ ± 0.3‰ and the product chloride an isotope effect of −6.5‰ ± 2.5‰, in the original positions of TCE from which the products were formed (95% confidence intervals. A greater difference would be expected for a position-specific reaction (chloride would exclusively reflect a primary isotope effect. These results therefore suggest that both vicinal chlorine substituents of TCE were reactive (intramolecular competition. This finding puts new constraints on mechanistic scenarios and favours either nucleophilic addition by Co(I or single electron transfer as reductive dehalogenation mechanisms.

  19. Sulfur isotope ratios and the origins of the aerosols and cloud droplets in California stratus

    International Nuclear Information System (INIS)

    Ludwig, F.L.

    1976-01-01

    Marine aerosols often have sulfur-to-chloride ratios greater than that found in seawater. Sulfur isotope ratios ( 34 S/ 32 S) were measured in aerosol and cloud droplet samples collected in the San Francisco Bay Area in an attempt to understand the processes that produce the observed sulfur-to-chloride ratios. Seawater sulfur usually has very high sulfur isotope ratios: fossil fuel sulfur tends to have smaller isotope ratios and sulfur of bacteriogenic origin still smaller. Samples collected in unpolluted marine air over the hills south of San Francisco had sulfur ratios that were significantly lower than the values for samples collected in nearby areas that were subject to urban pollution. The highest sulfur isotope ratios were found in the offshore seawater. The results suggest bacteriogenic origins, of the marine air sulfur aerosol material. The low isotope ratios in the marine air cannot be explained as a mixture of seawater sulfur and pollutant sulfur, because both tend to have higher isotope ratios. (Auth.)

  20. Biometrics from the carbon isotope ratio analysis of amino acids in human hair.

    Science.gov (United States)

    Jackson, Glen P; An, Yan; Konstantynova, Kateryna I; Rashaid, Ayat H B

    2015-01-01

    This study compares and contrasts the ability to classify individuals into different grouping factors through either bulk isotope ratio analysis or amino-acid-specific isotope ratio analysis of human hair. Using LC-IRMS, we measured the isotope ratios of 14 amino acids in hair proteins independently, and leucine/isoleucine as a co-eluting pair, to provide 15 variables for classification. Multivariate analysis confirmed that the essential amino acids and non-essential amino acids were mostly independent variables in the classification rules, thereby enabling the separation of dietary factors of isotope intake from intrinsic or phenotypic factors of isotope fractionation. Multivariate analysis revealed at least two potential sources of non-dietary factors influencing the carbon isotope ratio values of the amino acids in human hair: body mass index (BMI) and age. These results provide evidence that compound-specific isotope ratio analysis has the potential to go beyond region-of-origin or geospatial movements of individuals-obtainable through bulk isotope measurements-to the provision of physical and characteristic traits about the individuals, such as age and BMI. Further development and refinement, for example to genetic, metabolic, disease and hormonal factors could ultimately be of great assistance in forensic and clinical casework. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  1. Using hydrogen isotopes to assign origins of bats in the eastern United States

    Science.gov (United States)

    Eric R. Britzke; Susan C. Loeb; Keith A. Hobson; Christopher S. Romanek; Maarten J. Vonhof

    2009-01-01

    Stable hydrogen isotopes (dDs) in metabolically inert tissues such as feathers and hair provide a set of endogenous markers that may be useful for establishing migratory connectivity in animals. We tested the assumption...

  2. Equilibrium properties of dense hydrogen isotope gases based on the theory of simple fluids.

    Science.gov (United States)

    Kowalczyk, Piotr; MacElroy, J M D

    2006-08-03

    We present a new method for the prediction of the equilibrium properties of dense gases containing hydrogen isotopes. The proposed approach combines the Feynman-Hibbs effective potential method and a deconvolution scheme introduced by Weeks et al. The resulting equations of state and the chemical potentials as functions of pressure for each of the hydrogen isotope gases depend on a single set of Lennard-Jones parameters. In addition to its simplicity, the proposed method with optimized Lennard-Jones potential parameters accurately describes the equilibrium properties of hydrogen isotope fluids in the regime of moderate temperatures and pressures. The present approach should find applications in the nonlocal density functional theory of inhomogeneous quantum fluids and should also be of particular relevance to hydrogen (clean energy) storage and to the separation of quantum isotopes by novel nanomaterials.

  3. CRYOCOL a computer program to calculate the cryogenic distillation of hydrogen isotopes

    International Nuclear Information System (INIS)

    Douglas, S.R.

    1993-02-01

    This report describes the computer model and mathematical method coded into the AECL Research computer program CRYOCOL. The purpose of CRYOCOL is to calculate the separation of hydrogen isotopes by cryogenic distillation. (Author)

  4. Stable isotope ratio mass spectrometry and physical comparison for the forensic examination of grip-seal plastic bags.

    Science.gov (United States)

    Taylor, Erica; Carter, James F; Hill, Jenny C; Morton, Carolyn; Daeid, Niamh Nic; Sleeman, Richard

    2008-05-20

    Plastic bags are frequently used to package drugs, explosives and other contraband. There exists, therefore, a requirement in forensic casework to compare bags found at different locations. This is currently achieved almost exclusively by the use of physical comparisons such as birefringence patterns. This paper discusses some of the advantages and shortcomings of this approach, and presents stable isotope ratio mass spectrometry (IRMS) as a supplementary tool for effecting comparisons of this nature. Carbon and hydrogen isotopic data are presented for sixteen grip-seal plastic bags from a wide range of sources, in order to demonstrate the range of values which is likely to be encountered. Both isotopic and physical comparison (specifically birefringence) techniques are then applied to the analysis of rolls of bags from different manufacturing lots from a leading manufacturer. Both approaches are able to associate bags from a common production batch. IRMS can be applied to small fragments which are not amenable to physical comparisons, and is able to discriminate bags which could be confused using birefringence patterns alone. Similarly, in certain cases birefringence patterns discriminate bags with similar isotopic compositions. The two approaches are therefore complementary. When more than one isotopically distinct region exists within a bag (e.g. the grip-seal is distinct from the body) the ability to discriminate and associate bags is greatly increased.

  5. ANALYSIS OF RICIN TOXIN PREPARATIONS FOR CARBOHYDRATE AND FATTY ACID ABUNDANCE AND ISOTOPE RATIO INFORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Wunschel, David S.; Kreuzer-Martin, Helen W.; Antolick, Kathryn C.; Colburn, Heather A.; Moran, James J.; Melville, Angela M.

    2009-12-01

    employing a quadrupole MS system for compound identification and an isotope ratio MS for measuring the stable isotope ratios of deuterium and hydrogen (D/H) in fatty acids. Finally, the method for analyzing the compound abundance data is included. This study indicates that removal of ricinoleic acid is a conserved consequence of each processing step we tested. Furthermore, the stable isotope D/H ratio of ricinoleic acid distinguished between two of the three castor seed sources. Concentrations of arabinose, xylose, mannose, glucosamine and myo-inositol differentiated between crude or acetone extracted samples and samples produced by protein precipitation. Taken together these data illustrate the ability to distinguish between processes used to purify a ricin sample as well as potentially the source seeds.

  6. ITER hydrogen isotope separation system conceptual design description

    International Nuclear Information System (INIS)

    Busigin, A.; Sood, S.K.; Kveton, O.K.; Dinner, P.J.; Murdoch, D.K.; Leger, D.

    1990-01-01

    This paper presents integrated hydrogen Isotope Separation System (ISS) designs for ITER based on requirements for plasma exhaust processing, neutral beam injection deuterium cleanup, pellet injector propellant detritiation, waste water detritiation, and breeding blanket detritiation. Specific ISS designs are developed for a machine with an aqueous lithium salt blanket (ALSB) and a machine with a solid ceramic breeding blanket (SBB). The differences in the ISS designs arising from the different blanket concepts are highlighted. It is found that the ISS designs for the two blanket concepts considered are very similar with the only major difference being the requirement for an additional large water distillation column for ALSB water detritiation. The extraction of tritium from the ALSB is based on flash evaporation to separate the blanket water from the dissolved Li salt, with the tritiated water then being fed to the ISS for detritiation. This technology is considered to be relatively well understood in comparison to front-end processes for SBB detritiation. In the design of the cryogenic distillation portion of the ISS, it was found that the tritium inventory could be very large (> 600 g) unless specific design measures were taken to reduce it. In the designs which are presented, the tritium inventory has been reduced to about 180 g, which is less than the ITER single-failure release limit of 200 g. Further design optimization and isolation of components is expected to reduce the inventory further. (orig.)

  7. Retention characteristics of hydrogen isotopes in JT-60U

    International Nuclear Information System (INIS)

    Masaki, K.; Sugiyama, K.; Hayashi, T.; Ochiai, K.; Gotoh, Y.; Shibahara, T.; Hirohata, Y.; Oya, Y.; Miya, N.; Tanabe, T.

    2005-01-01

    Erosion/deposition distribution and hydrogen isotope behavior in the JT-60U plasma-facing wall were investigated. Distribution of the tritium, which was produced by D-D nuclear reaction, was not correlated with erosion/deposition distribution. The tritium distribution can be explained by the distribution of high-energy tritium ion-implantation due to ripple loss. Deuterium distribution in the divertor region was different from the tritium distribution and not well correlated with the deposition. The highest D/C was ∼0.05 at the bottom of the outer dome wing, which is much less than that observed in other tokamaks. For the deuterium retention, at least two retention processes (ion-implantation and co-deposition) were found on the dome region. The systematic dust collection gave the small amount of dust (∼7 g: 0.2 mg/s production) in the whole vessel of JT-60U. Deposition was observed at the remote area of the outer divertor region

  8. On order reduction in hydrogen isotope distillation models

    International Nuclear Information System (INIS)

    Sarigiannis, D.A.

    1994-01-01

    The design integration of the fuel processing system for the next generation fusion reactor plants (such as ITER and beyond) requires the enhancement of safety features related to the operation of the system. The current drive for inherent safety of hazardous chemical plants warrants the minimization of active toxic or radioactive inventories and the identification of process pathways with minimal risk of accidental or routine releases. New mathematical and numerical tools have been developed for the dynamic simulation and optimization of the safety characteristics related to tritium in all its forms in the fusion fuel processing system. The separation of hydrogen isotopes by cryogenic distillation is a key process therein, due to the importance of the separation performance for the quality of the fuel mixture and the on site inventory, the increased energy requirements for cryogenic operation, and the high order of mathematical complexity required for accurate models, able to predict the transient as well as the steady state behavior of the process. The modeling methodology described here is a part of a new dynamic simulation code that captures the inventory dynamics of all the species in the fusion fuel processing plant. The significant reduction of the computational effort and time required by this code will permit designers to easily explore a variety of design and technology options and assess their impact on the overall power plant safety

  9. A Graphite Isotope Ratio Method: A Primer on Estimating Plutonium Production in Graphite Moderated Reactors

    International Nuclear Information System (INIS)

    Gesh, Christopher J.

    2004-01-01

    The Graphite Isotope Ratio Method (GIRM) is a technique used to estimate the total plutonium production in a graphite-moderated reactor. The cumulative plutonium production in that reactor can be accurately determined by measuring neutron irradiation induced isotopic ratio changes in certain impurity elements within the graphite moderator. The method does not require detailed knowledge of a reactor's operating history, although that knowledge can decrease the uncertainty of the production estimate. The basic premise of the Graphite Isotope Ratio Method is that the fluence in non-fuel core components is directly related to the cumulative plutonium production in the nuclear fuel

  10. Studies in the determination of lead isotope ratios by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Date, A.R.; Yuk Ying Cheung

    1987-01-01

    The application of ICP-MS to the determination of lead isotope ratios in geological materials is described. Data presented for a series of lead mineral concentrates are compared with reference values obtained by conventional solid source thermal ionisation mass spectrometry. The simultaneous determination of lead isotope ratios and trace elements is carried out in a rapid analysis mode. The application of an electrothermal vaporisation technique for small solution aliquots is described. Lead isotope ratio data for the United States Geological Survey standard reference silicate rock BCR-1, obtained without separation of lead from the matrix, are compared with previously published values obtained after separation. (author)

  11. Results from an interlaboratory exercise on the determination of plutonium isotopic ratios by gamma spectrometry

    International Nuclear Information System (INIS)

    Ottmar, H.

    1981-07-01

    Results form interlaboratory comparison measurements on the determination of plutonium isotopic ratios by gamma spectrometry, organized by the ESARDA Working Group on Techniques and Standards for Nondestructive Analysis, are presented and discussed. Nine laboratories from nine countries or international organizations participated in the intercomparison exercise, which included both laboratories' own measurements on the plutonium isotopic reference materials NBS-SRM 946, 947, 948 and comparison analyses of gamma spectra from these materials distributed to the participating laboratories. Results from the intercomparison analyses have been used to reevaluate some gamma branching intensity ratios required for plutonium isotopic ratio measurements. (orig.) [de

  12. Derivation of basic equations for rigorous dynamic simulation of cryogenic distillation column for hydrogen isotope separation

    International Nuclear Information System (INIS)

    Kinoshita, Masahiro; Naruse, Yuji

    1981-08-01

    The basic equations are derived for rigorous dynamic simulation of cryogenic distillation columns for hydrogen isotope separation. The model accounts for such factors as differences in latent heat of vaporization among the six isotopic species of molecular hydrogen, decay heat of tritium, heat transfer through the column wall and nonideality of the solutions. Provision is also made for simulation of columns with multiple feeds and multiple sidestreams. (author)

  13. Adaptation of Boynton's mathematical model to hydrogen isotope separation column by cryogenic distillation

    International Nuclear Information System (INIS)

    Kinoshita, Masahiro; Naruse, Yuji

    1981-08-01

    Boynton's mathematical simulation procedure for multi-component distillation calculations has the advantage that the Jacobian matrix is calculated analytically. The purpose of the present study is to adapt this procedure to hydrogen isotope separation columns by cryogenic distillation. The Boynton's model is modified so that the model can incorporate decay heat of tritium, nonideality of the hydrogen isotope solutions, multiple feeds and multiple sidestreams. Basic equations are derived and the mathematical simulation procedure is briefly explained. (author)

  14. Application of TIMS in isotope correlations for determining the isotope ratios of plutonium

    International Nuclear Information System (INIS)

    Alamelu, D.; Aggarwal, S.K.

    2003-01-01

    Thermal ionisation mass spectrometry (TIMS) is a well-recognized technique for determining the isotopic composition of Pu in irradiated nuclear fuel samples. Other mass spectrometric methods such as ICPMS, SIMS can also be employed for the isotopic analysis of Pu. In the event of non-availability of a mass spectrometer, other techniques such as gamma spectrometry and alpha spectrometry can also be used. They have a limited applicability since data on all the Pu isotopes cannot be obtained

  15. Tracing lead pollution sources in abandoned mine areas using stable Pb isotope ratios.

    Science.gov (United States)

    Yoo, Eun-Jin; Lee, Jung-A; Park, Jae-Seon; Lee, Khanghyun; Lee, Won-Seok; Han, Jin-Seok; Choi, Jong-Woo

    2014-02-01

    This study focused on Pb isotope ratios of sediments in areas around an abandoned mine to determine if the ratios can be used as a source tracer. For pretreatment, sediment samples were dissolved with mixed acids, and a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, Nu plasma II) was used to investigate the Pb isotopic composition of the samples. The measured isotope ratios were then corrected for instrumental mass fractionation by measuring the (203)Tl/(205)Tl ratio. Repeated measurements with the NIST SRM 981 reference material showed that the precision of all ratios was below 104 ppm (±2σ) for 50 ng/g. The isotope ratios ((207)Pb/(206)Pb) found were 0.85073 ± 0.0004~0.85373 ± 0.0003 for the main stream, while they were 0.83736 ± 0.0010 for the tributary and 0.84393 ± 0.0002 for the confluence. A binary mixing equation for isotope ratios showed that the contributions of mine lead to neighboring areas were up to 60%. Therefore, Pb isotope ratios can be a good source tracer for areas around abandoned mines.

  16. Features of the spectroscopic determination of the isotope composition of trace amounts of hydrogen in helium

    International Nuclear Information System (INIS)

    Nemets, V.M.; Petrov, A.A.; Solov'ev, A.A.

    1986-01-01

    The investigation of the magnitude of the isotope effect in the intensiti of the beta lines of the Balmer series was carried out with the excitation of a high-frequency discharge in a quartz tube having a diameter of ca.6.5 at pressures of the gaseous mixture ranging from 1 to 70 kPa. From the experimental results here it follows that as the isotopes of hydrogen are diluted with helium, the value of K decreases from 1.2-1.1 to 0.84-0.86, and the maximum of the plots of K= f(P) broaden and move toward higher pressures. In order to account for the laws obtained, the authors examined a set of elementary processes and reactions for which the isotope-related differences in the rate constants (alpha) can influence the relative concentrations of the excited atoms of the isotopes of hydrogen in a discharge. The physical model presented in this paper of the shaping of the isotope effects in the atomic spectrum of hydrogen makes it possible to account for the observed laws governing the excitation of a discharge in a mixture of the isotopes of hydrogen with helium and thus greatly facilitates the selection of the optimal conditions for the excitation of the analytical spectrum in devising procedures for the spectroscopic isotope determination of trace impurities of hydrogen in helium

  17. Hydrogen Isotopes in Amino Acids and Soils Offer New Potential to Study Complex Processes

    Science.gov (United States)

    Fogel, M. L.; Newsome, S. D.; Williams, E. K.; Bradley, C. J.; Griffin, P.; Nakamoto, B. J.

    2016-12-01

    Hydrogen isotopes have been analyzed extensively in the earth and biogeosciences to trace water through various environmental systems. The majority of the measurements have been made on water in rocks and minerals (inorganic) or non-exchangeable H in lipids (organic), important biomarkers that represent a small fraction of the organic molecules synthesized by living organisms. Our lab has been investigating hydrogen isotopes in amino acids and complex soil organic matter, which have traditionally been thought to be too complex to interpret owing to complications from potentially exchangeable hydrogen. For the amino acids, we show how hydrogen in amino acids originates from two sources, food and water, and demonstrate that hydrogen isotopes can be routed directly between organisms. Amino acid hydrogen isotopes may unravel cycling in extremophiles in order to discover novel biochemical pathways central to the organism. For soil organic matter, recent approaches to understanding the origin of soil organic matter are pointing towards root exudates along with microbial biomass as the source, rather than aboveground leaf litter. Having an isotope tracer in very complex, potentially exchangeable organic matter can be handled with careful experimentation. Although no new instrumentation is being used per se, extension of classes of organic matter to isotope measurements has potential to open up new doors for understanding organic matter cycling on earth and in planetary materials.

  18. Ratio of carbon monoxide to molecular hydrogen in interstellar dark clouds

    International Nuclear Information System (INIS)

    Dickman, R.L.; Rensselaer Polytechnic Institute; and The Ivan A. Getting Laboratories, The Aerospace Corporation)

    1978-01-01

    Carbon monoxide and molecular hydrogen column densities are compared at various locations within 38 interstellar dark clouds. CO column densities were obtained from radio observations of the J=1→0 transitions of the 12 C 16 O and 13 C 16 O isotopic species of the molecule. Corresponding H 2 column densities were inferred by means of visual extinctions derived from star counts, since it is argued that the standard gas-to-extinction ratio can be expected to remain valid in the clouds studied. For locations in the sources possessing line-of-sight visual extinctions in the approximate range 1.5 -2 ) = (5.0 +- 2.5) x 10 5 N 13 between molecular hydrogen and 13 CO LTE column densities. The carbon monoxide molecule can therefore be used as a quantitative ''tracer'' for the (directly unobservable) H 2 content of dark clouds. The above relationship implies that at least approx.12% of the gas-phase carbon in the clouds studied is in the form of CO, provided that the clouds are assumed to be chemically homogeneous. Langer's ion-molecule chemistry for dark clouds appears to agree well with the present work if the fractionation channel of Watson, Anicich, and Huntress is included

  19. On depth profiling of hydrogen and helium isotopes and its application to ion-implantation studies

    International Nuclear Information System (INIS)

    Boettiger, J.

    1979-01-01

    The thesis is divided into two parts, the first being a general review of the experimental methods for depth profiling of light isotopes, where ion beams are used. In the second part, studies of ion implantation of hydrogen and helium isotopes, applying the techniques discussed in the first part, are described. The paper summarizes recent experimental results and discusses recent developments. (Auth.)

  20. Carbon, Chlorine, and Hydrogen Isotope Fractionation in Transformation of TCE to Ethene by a Dehalococcoides Culture

    NARCIS (Netherlands)

    Kuder, T.; van Breukelen, B.M.; Vanderford, M.; Philip, P.

    2013-01-01

    Carbon (C), chlorine (Cl), and hydrogen (H) isotope effects were determined during dechlorination of TCE to ethene by a mixed Dehalococcoides (Dhc) culture. The C isotope effects for the dechlorination steps were consistent with data published in the past for reductive dechlorination (RD) by Dhc.

  1. Determination of the isotopic ratio 235U/238U in UF6 using quadrupole mass spectrometry

    International Nuclear Information System (INIS)

    Kusahara, Helena Sueco

    1979-01-01

    In this work measurements of isotope ratios 235 U / 23 '8U in uranium hexafluoride are carried out using a quadrupole mass spectrometer. The operational parameters, which affect the final precision of the results, are standardized. Optimized procedures for the preparation of uranium hexafluoride samples by fluorination of uranium oxides using cobalt trifluoride method are established. Careful attention is given to the process of purification of uranium hexafluoride samples by fractional distillation. Adequate statistical methods for analysing the results obtained for single ratio measurements as well as the ratio ' of isotopic ratios of sample and standard ar.e developed. A precision of about 10 -4 for single ratio measurements and accuracy of about 0,3% for the ratio of sample and standard ratios are obtained. These results agree with the values which have been obtained using magnetic mass spectrometers. The procedures and methods established in this work can be employed in the systematic uranium isotope analysis in UF 6 form. (author)

  2. The calibration of the intramolecular nitrogen isotope distribution in nitrous oxide measured by isotope ratio mass spectrometry.

    Science.gov (United States)

    Westley, Marian B; Popp, Brian N; Rust, Terri M

    2007-01-01

    Two alternative approaches for the calibration of the intramolecular nitrogen isotope distribution in nitrous oxide using isotope ratio mass spectrometry have yielded a difference in the 15N site preference (defined as the difference between the delta15N of the central and end position nitrogen in NNO) of tropospheric N2O of almost 30 per thousand. One approach is based on adding small amounts of labeled 15N2O to the N2O reference gas and tracking the subsequent changes in m/z 30, 31, 44, 45 and 46, and this yields a 15N site preference of 46.3 +/- 1.4 per thousand for tropospheric N2O. The other involves the synthesis of N2O by thermal decomposition of isotopically characterized ammonium nitrate and yields a 15N site preference of 18.7 +/- 2.2 per thousand for tropospheric N2O. Both approaches neglect to fully account for isotope effects associated with the formation of NO+ fragment ions from the different isotopic species of N2O in the ion source of a mass spectrometer. These effects vary with conditions in the ion source and make it impossible to reproduce a calibration based on the addition of isotopically enriched N2O on mass spectrometers with different ion source configurations. These effects have a much smaller impact on the comparison of a laboratory reference gas with N2O synthesized from isotopically characterized ammonium nitrate. This second approach was successfully replicated and leads us to advocate the acceptance of the site preference value 18.7 +/- 2.2 per thousand for tropospheric N2O as the provisional community standard until further independent calibrations are developed and validated. We present a technique for evaluating the isotope effects associated with fragment ion formation and revised equations for converting ion signal ratios into isotopomer ratios. Copyright 2007 John Wiley & Sons, Ltd.

  3. Evidence from Hydrogen Isotopes in Meteorites for a Subsurface Hydrogen Reservoir on Mars

    Science.gov (United States)

    Usui, Tomohiro; Alexander, Conel M. O'D.; Wang, Jianhua; Simon, Justin I.; Jones, John H.

    2015-01-01

    The surface geology and geomorphology of Mars indicates that it was once warm enough to maintain a large body of liquid water on its surface, though such a warm environment might have been transient. The transition to the present cold and dry Mars is closely linked to the history of surface water, yet the evolution of surficial water is poorly constrained. We have conducted in situ hydrogen isotope (D/H) analyses of quenched and impact glasses in three Martian meteorites (Yamato 980459, EETA79001, LAR 06319) by Cameca ims-6f at Digital Terrain Models (DTM) following the methods of [1]. The hydrogen isotope analyses provide evidence for the existence of a distinct but ubiquitous water/ice reservoir (D/H = 2-3 times Earth's ocean water: Standard Mean Ocean Water (SMOW)) that lasted from at least the time when the meteorites crystallized (173-472 Ma) to the time they were ejected by impacts (0.7-3.3 Ma), but possibly much longer [2]. The origin of this reservoir appears to predate the current Martian atmospheric water (D/H equals approximately 5-6 times SMOW) and is unlikely to be a simple mixture of atmospheric and primordial water retained in the Martian mantle (D/H is approximately equal to SMOW [1]). Given the fact that this intermediate-D/H reservoir (2-3 times SMOW) is observed in a diverse range of Martian materials with different ages (e.g., SNC (Shergottites, Nakhlites, Chassignites) meteorites, including shergottites such as ALH 84001; and Curiosity surface data [3]), we conclude that this intermediate-D/H reservoir is likely a global surficial feature that has remained relatively intact over geologic time. We propose that this reservoir represents either hydrated crust and/or ground ice interbedded within sediments. Our results corroborate the hypothesis that a buried cryosphere accounts for a large part of the initial water budget of Mars.

  4. The Potential of Isotope Ratio Mass Spectrometry (IRMS) and Gas Chromatography-IRMS Analysis of Triacetone Triperoxide in Forensic Explosives Investigations.

    Science.gov (United States)

    Bezemer, Karlijn D B; Koeberg, Mattijs; van der Heijden, Antoine E D M; van Driel, Chris A; Blaga, Cornelia; Bruinsma, Jildert; van Asten, Arian C

    2016-09-01

    Studying links between triacetone triperoxide (TATP) samples from crime scenes and suspects can assist in criminal investigations. Isotope ratio mass spectrometry (IRMS) and gas chromatography (GC)-IRMS were used to measure the isotopic compositions of TATP and its precursors acetone and hydrogen peroxide. In total, 31 TATP samples were synthesized with different raw material combinations and reaction conditions. For carbon, a good differentiation and a linear relationship were observed for acetone-TATP combinations. The extent of negative (δ(13) C) fractionation depended on the reaction yield. Limited enrichment was observed for the hydrogen isotope (δ(2) H) values of the TATP samples probably due to a constant exchange of hydrogen atoms in aqueous solution. For oxygen (δ(18) O), the small isotopic range and excess of water in hydrogen peroxide resulted in poor differentiation. GC-IRMS and IRMS data were comparable except for one TATP sample prepared with high acid concentration demonstrating the potential of compound-specific isotope analysis. Carbon IRMS has practical use in forensic TATP investigations. © 2016 American Academy of Forensic Sciences.

  5. Lead isotope ratios as a tracer for lead contamination sources: A lake Andong case study

    Directory of Open Access Journals (Sweden)

    Kim Y. H

    2013-04-01

    Full Text Available The objective of this study was to evaluate stable Pb isotope signatures as a tracer for Pb contamination in Lake Andong. For Pb isotope analysis, we collected water and sediment from Lake Andong, particles in the air, soils, and stream water, mine tailings, sludge and wastewater from zinc smelting around lake Andong watershed. The results showed that Pb isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb for zinc concentrate were 18.809 ± 0.322, 15.650 ± 0.062, and 38.728 ± 0.421, respectively. In wastewater, isotopic ratio values (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb were 17.363 ± 0.133, 15.550 ± 0.025, and 37.217 ± 0.092, respectively. Additionally, isotopic ratio values (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb for sludge were 17.515 ± 0.155, 15.537 ± 0.018, and 37.357 ± 0.173, respectively. These values were similar to those in zinc and lead concentrate originated from Canada and South America. In contrast, Pb isotope ratios of soil, tailings and sediment from Lake Andong were similar to those of Korean ore. Atmospheric particles showed different patterns of Pb isotope ratios from sediments, soils, and zinc smelting and this needs further investigation in order to identify atmospheric Pb sources.

  6. Compilation of minimum and maximum isotope ratios of selected elements in naturally occurring terrestrial materials and reagents

    Science.gov (United States)

    Coplen, T.B.; Hopple, J.A.; Böhlke, J.K.; Peiser, H.S.; Rieder, S.E.; Krouse, H.R.; Rosman, K.J.R.; Ding, T.; Vocke, R.D.; Revesz, K.M.; Lamberty, A.; Taylor, P.; De Bievre, P.

    2002-01-01

    Documented variations in the isotopic compositions of some chemical elements are responsible for expanded uncertainties in the standard atomic weights published by the Commission on Atomic Weights and Isotopic Abundances of the International Union of Pure and Applied Chemistry. This report summarizes reported variations in the isotopic compositions of 20 elements that are due to physical and chemical fractionation processes (not due to radioactive decay) and their effects on the standard atomic weight uncertainties. For 11 of those elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, silicon, sulfur, chlorine, copper, and selenium), standard atomic weight uncertainties have been assigned values that are substantially larger than analytical uncertainties because of common isotope abundance variations in materials of natural terrestrial origin. For 2 elements (chromium and thallium), recently reported isotope abundance variations potentially are large enough to result in future expansion of their atomic weight uncertainties. For 7 elements (magnesium, calcium, iron, zinc, molybdenum, palladium, and tellurium), documented isotope-abundance variations in materials of natural terrestrial origin are too small to have a significant effect on their standard atomic weight uncertainties. This compilation indicates the extent to which the atomic weight of an element in a given material may differ from the standard atomic weight of the element. For most elements given above, data are graphically illustrated by a diagram in which the materials are specified in the ordinate and the compositional ranges are plotted along the abscissa in scales of (1) atomic weight, (2) mole fraction of a selected isotope, and (3) delta value of a selected isotope ratio. There are no internationally distributed isotopic reference materials for the elements zinc, selenium, molybdenum, palladium, and tellurium. Preparation of such materials will help to make isotope ratio measurements among

  7. Constraints on Weathering from Riverine Magnesium Isotope Ratios

    DEFF Research Database (Denmark)

    Wiechert, Uwe; Ullmann, Clemens Vinzenz; Meixner, Anette

    and industrialized regions, the d26Mg values mirror the lithologies of the catchment areas: the Danubian catchment is dominated by carbonatic lithologies and in the Danube dissolved magnesium exhibits the most negative d26Mg values between -1.85 and -1.70 ‰. The mainly siliceous catchment of the river Elbe causes....... Simple mass balance calculations on the basis of the magnesium isotopes obtained for the investigated rivers imply 26 to 59 % magnesium derived from carbonatic lithologies and 41 to 74 % magnesium from siliceous lithologies. This is in contrast to estimates using conventional methods for the tribute...

  8. Isotopic ratios D/H and 15N/14N in giant planets

    Science.gov (United States)

    Marboeuf, Ulysse; Thiabaud, Amaury; Alibert, Yann; Benz, Willy

    2018-04-01

    The determination of isotopic ratios in planets is important since it allows us to investigate the origins and initial composition of materials. The present work aims to determine the possible range of values for isotopic ratios D/H and 15N/14N in giant planets. The main objective is to provide valuable theoretical assumptions on the isotopic composition of giant planets, their internal structure, and the main reservoirs of species. We use models of ice formation and planet formation that compute the composition of ices and gas accreted in the core and the envelope of planets. Assuming a single initial value for isotopic ratios in volatile species, and disruption of planetesimals in the envelope of gaseous planets, we obtain a wide variety of D/H and 15N/14N ratios in low-mass planets (≤100 Mearth) due to the migration pathway of planets, the accretion time of gas species whose relative abundance evolves with time, and isotope exchanges among species. If giant planets with mass greater than 100 Mearth have solar isotopic ratios such as Jupiter and Saturn due to their higher envelope mass, Neptune-type planets present values ranging between one and three times the solar value. It seems therefore difficult to use isotopic ratios in the envelope of these planets to get information about their formation in the disc. For giant planets, the ratios allow us to constrain the mass fraction of volatile species in the envelope needed to reproduce the observational data by assuming initial values for isotopic ratios in volatile species.

  9. Graphite Isotope Ratio Method Development Report: Irradiation Test Demonstration of Uranium as a Low Fluence Indicator

    International Nuclear Information System (INIS)

    Reid, B.D.; Gerlach, D.C.; Love, E.F.; McNeece, J.P.; Livingston, J.V.; Greenwood, L.R.; Petersen, S.L.; Morgan, W.C.

    1999-01-01

    This report describes an irradiation test designed to investigate the suitability of uranium as a graphite isotope ratio method (GIRM) low fluence indicator. GIRM is a demonstrated concept that gives a graphite-moderated reactor's lifetime production based on measuring changes in the isotopic ratio of elements known to exist in trace quantities within reactor-grade graphite. Appendix I of this report provides a tutorial on the GIRM concept

  10. Experimental studies on hydrogen isotopic deuterium from gas to liquid phase by catalytic exchange

    International Nuclear Information System (INIS)

    Luo Yangming; Wang Heyi; Liu Jun; Fu Zhonghua; Wang Changbin; Han Jun; Xia Xiulong; Tang Lei

    2005-01-01

    The experimental studies on hydrogen isotopic deuterium from gas to liquid phase were completed by mixed ratio 1:4 of Pt-SDB hydrophobic catalyst and hydrophilic packing. The influencing factors on number of transfer units (NTU) and transformation efficiencies of deuterium were researched. The results show that preferable NTU can be obtained by choosing suitable operational temperature and flux of exchange gas. The transformation rate increases with increasing liquid flux, but it cannot obviously be improved when liquid flux attains some level. The length of catalytic column has an obvious influence on transformation rate and 90% of transformation rate is obtained by 4 m column length at gas flux with 2 m 3 /h, liquid flux with 1-2 kg/h and 45 degree C. (author)

  11. Separation of rate processes for isotopic exchange between hydrogen and liquid water in packed columns 10

    International Nuclear Information System (INIS)

    Butler, J.P.; Hartog, J. den; Goodale, J.W.; Rolston, J.H.

    1977-01-01

    Wetproofed platinum catalysts in packed columns promote isotopic exchange between counter-current streams of hydrogen saturated with water vapour and liquid water. The net rate of deuterium transfer from isotopically enriched hydrogen has been measured and separated into two rate processes involving the transfer of deuterium from hydrogen to water vapour and from water vapour to liquid. These are compared with independent measurements of the two rate processes to test the two-step successive exchange model for trickle bed reactors. The separated transfer rates are independent of bed height and characterize the deuterium concentrations of each stream along the length of the bed. The dependences of the transfer rates upon hydrogen and liquid flow, hydrogen pressure, platinum loading and the effect of dilution of the hydrophobic catalyst with inert hydrophilic packing are reported. The results indicate a third process may be important in the transfer of deuterium between hydrogen and liquid water. (author)

  12. Process for the exchange of hydrogen isotopes using a catalyst packed bed assembly

    International Nuclear Information System (INIS)

    Butler, J.P.; den Hartog, J.; Molson, F.W.R.

    1978-01-01

    A process for the exchange of hydrogen isotopes between streams of gaseous hydrogen and liquid water is described, wherein the streams of liquid water and gaseous hydrogen are simultaneously brought into contact with one another and a catalyst packed bed assembly while at a temperature in the range 273 0 to 573 0 K. The catalyst packed bed assembly may be composed of discrete carrier bodies of e.g. ceramics, metals, fibrous materials or synthetic plastics with catalytically active metal crystallites selected from Group VIII of the Periodic Table, partially enclosed in and bonded to the carrier bodies by a water repellent, water vapor and hydrogen gas permeable, porous, polymeric material, and discrete packing bodies having an exterior surface which is substantially hydrophilic and relatively noncatalytically active with regard to hydrogen isotope exchange between hydrogen gas and water vapor to that of the catalyst bodies

  13. Estimation of Physical Properties for Hydrogen Isotopes Using Aspen Plus Simulator

    International Nuclear Information System (INIS)

    Cho, Jung Ho; Yun, Sei Hun; Cho, Seung Yon; Chang, Min Ho; Kang, Hyun Goo; Jung, Ki Jung; Kim, Dong Min

    2009-01-01

    Hydrogen isotopes are H 2 , HD, D 2 , H 2 , HD, D 2 , HT, DT and T 2 . Among the hydrogen isotopes, the physical properties of H2, HD and D+2 are included in the Aspen Plus, however HT, D T and T 2 are not included. In this study, various thermodynamic properties were estimated for six components of isotopes by use of the fixed properties and temperature-dependent properties. To estimate thermodynamic properties, Soave modified Redlich-Kwong equation of state and Aspenplus simulator was used. The results were verified and compared with by PRO/II with PROVISION of Invensys

  14. Preliminary results of oxygen isotope ratio measurement with a particle-gamma coincidence method

    Energy Technology Data Exchange (ETDEWEB)

    Borysiuk, Maciek, E-mail: maciek.borysiuk@pixe.lth.se; Kristiansson, Per; Ros, Linus; Abdel, Nassem S.; Elfman, Mikael; Nilsson, Charlotta; Pallon, Jan

    2015-04-01

    The possibility to study variations in the oxygen isotopic ratio with photon tagged nuclear reaction analysis (pNRA) is evaluated in the current work. The experiment described in the article was performed at Lund Ion Beam Analysis Facility (LIBAF) with a 2 MeV deuteron beam. Isotopic fractionation of light elements such as carbon, oxygen and nitrogen is the basis of many analytical tools in hydrology, geology, paleobiology and paleogeology. IBA methods provide one possible tool for measurement of isotopic content. During this experimental run we focused on measurement of the oxygen isotopic ratio. The measurement of stable isotopes of oxygen has a number of applications; the particular one driving the current investigation belongs to the field of astrogeology and specifically evaluation of fossil extraterrestrial material. There are three stable isotopes of oxygen: {sup 16}O, {sup 17}O and {sup 18}O. We procured samples highly enriched with all three isotopes. Isotopes {sup 16}O and {sup 18}O were easily detected in the enriched samples, but no significant signal from {sup 17}O was detected in the same samples. The measured yield was too low to detect {sup 18}O in a sample with natural abundances of oxygen isotopes, at least in the current experimental setup, but the spectral line from the reaction with {sup 16}O was clearly visible.

  15. The influence of column temperature on the hydrogen isotopes separation performance of FDC

    International Nuclear Information System (INIS)

    Deng Xiaojun; Luo Deli; Qin Cheng; Yang Wan; Huang Guoqiang; Huang Zhiyong

    2014-01-01

    Frontal displacement chromatography (FDC) is a promising method for hydrogen isotopes separation with obvious advantages such as simple operation process, low tritium retention in system and easy to scale up, etc. We designed and constructed a FDC device using Pd-Al 2 O 3 as separation material in previous study, and the feasibility of FDC for hydrogen isotopes separation was confirmed. On the basis of the results, a series of experiments at different column temperatures were carried out to investigate the temperature influence to the separation performance, with the composition of (5 ± 0.1)% H 2 -(5 ± 0.1)% D 2 -(90 ± 0.1)% Ar of feed gas. Experiments were carried out at the temperature of 303K, 273K, 263K, 253K, 213K, at the gas flow rate of 15 mL (NTP)/min. The results indicated that lower temperature, higher enrichment factor while the feed gas composition and the gas flow rate are definite; lower temperature, shorter 'separation transition state', and then better separation efficiency. The deuterium enrichment factor became 65 from l.5 while the temperature decreased to 273K from 303K. It also showed that the deuterium recovery ratio and the deuterium abundance of product gas increases with the temperature decrease except for the case of 303K. At the temperature of 273K and below, the deuterium recovery ratio were all higher than 42%, deuterium abundance of product were all larger than 98%, and the maximum of deuterium abundance at 213K was 99.8%. (authors)

  16. The thermal history of char as disclosed by carbon isotope ratios

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Ambus, Per; Ahrenfeldt, Jesper

    In laboratory experiments, biomass char was produced under controlled conditions using wood chips from French pinewood. Different char qualities were obtained by pyrolysing the biomass at similar heating rates with end-temperatures ranging from 250 to 1000 o C. The char was analysed by flash...... pyrolysis and isotope ratio mass spectrometry. The results demonstrate that the temperature history of the char is reflected in the fine variation of carbon isotopes. The compound classes responsible for the variation were identified. Key words: Isotope ratio, flash pyrolysis, hot gas cleaning...

  17. Differentiation of endogenous and exogenous steroids by gas chromatography-combustion-mass spectrometry isotope ratio

    International Nuclear Information System (INIS)

    Montes de Oca Porto, Rodny; Rosado Perez, Aristides; Correa Vidal, Margarita Teresa

    2007-01-01

    Urinary steroids profiles are used to control the misuse of endogenous steroids such as testosterone and dihydrotestosterone. The testosterone/epistestosterone ratio, measured by Gas Chromatography-Mass Spectrometry, is used to control testosterone administration. When T/E ratio is higher than 4, consumption of testosterone or its precursors is suspected. Recent researches have demonstrated the effectiveness of Carbon Isotope Ratio Mass Spectrometry to detect and confirm endogenous steroids administration. The ratio of the two stable carbon isotopes 1 3 C and 1 2 C allows the differentiation of natural and synthetic steroids because synthetic steroids have lower 1 3 C abundance. In fact, the carbon isotope ratios can be used to determine endogenous steroids administration even when testosterone/epistestosterone ratio is at its normal value. In the current work, some of the most important aspects related to differentiation of endogenous and exogenous steroids by means of Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry are discussed. Also, this article provides a review about the purification and sample preparation previous to the analysis, and diet effects on carbon isotope ratio of endogenous anabolics steroids is presented too

  18. Assessment of methods for analyzing gaseous mixtures of hydrogen isotopes and helium

    International Nuclear Information System (INIS)

    Attalla, A.; Bishop, C.T.; Bohl, D.R.; Buxton, T.L.; Sprague, R.E.; Warner, D.K.

    1976-01-01

    Mass spectrographic methods have served well in the past to analyze gaseous mixtures of the hydrogen isotopes. Alternate methods of analyses are reviewed which offer wider ranges and variety of isotopic determinations. This report describes possible improvements of the mass spectrographic determinations, gas chromatography, anti-Stokes Raman spectroscopy, microwave-induced optical emission spectroscopy, and methods of measuring tritium using radiation detection devices. Precision, accuracy, limitations, and costs are included for some of the methods mentioned. Costs range from $70,000 for the anti-Stokes Raman spectroscopy equipment, which can determine hydrogen isotopes but not helium, to less than $10,000 for the gas chromatographic equipment, which can determine hydrogen isotopes and helium with precision and accuracy comparable to those of the mass spectrometer

  19. The Influence of Irradiation Regimes on Retention Hydrogen Isotopes in Structural Materials

    International Nuclear Information System (INIS)

    Zaluzhnyi, A.

    2007-01-01

    Full text of publication follows: In the present work was investigated the influence of irradiation regimes on retention hydrogen isotopes in samples of austenitic steel during heating. The samples of studied materials were irradiated both in the reactor and by hydrogen isotopes ions of different energies and fluencies bombardment in an accelerator. Kinetic of hydrogen release from the samples worked with deuterium plasma was investigated. The following results were obtained. Heating the irradiate d samples of steel (irradiated in the reactor or by hydrogen isotopes ions bombardment), which have been kept in normal temperature during quite a long period after the irradiation, a shift of the diffusion peak of hydrogen release to higher temperatures, comparing to no irradiated samples, was observed. It means that atoms of hydrogen in the irradiated sample were caught by radiation defects, which are very effective as traps for hydrogen atoms till quite high temperatures (700 K). The worked out analysis of the received results supposes that vacancy complexes. On thermodesorption curves of hydrogen release from irradiated samples of austenitic steels a high temperature peak (900-1000 K) was observed because of dissociation of hydrogen containing compounds in micro pores. During investigations of hydrogen release from irradiated samples of austenitic steel, after it had been saturated with hydrogen plasma, abnormally big blisters were registered with cover thickness of about 1 mkm. Three peaks were observed on the thermodesorption curves of hydrogen release from irradiated samples, contained blisters. The low temperature spike (∼500 K) was showed to correspond to hydrogen release because of its resolution from blisters, where it was in molecular form. The high temperature peak (∼900 K) corresponds to hydrogen release from dissociating blisters, which contain hydrocarbons. The mechanism of abnormal blisters generation is offered. Inasmuch methane is not soluble in

  20. Fractionation of oxygen and hydrogen isotopes at the hydrate gas forming in the sea sediments

    International Nuclear Information System (INIS)

    Pashkina, V.I.; Esikov, A.D.

    1990-01-01

    The paper gives data on isotope composition of interstitial and near-bottom waters sampled in a region of gas-hydrate formation in the Sea of Okhotsk. The studies show that heavy isotopes of oxygen and hydrogen is used in gas-hydrate formation, with the result that isotope composition of its constitution water constitutes δ 18 O=+1.99per mille, δD=+23per mille relatively to SMOW. Formation of autogenic carbonates leads to isotope exchange with interstitial water wich, in turn, changes its primary isotope composition in the direction of increasing of O-18 content. The near-bottom waters are isotope-light relatively to the SMOW standard and to the mean isotope composition of interstitial water in the studied region of gas-hydrate spreading. (orig.) [de

  1. Determination of stable isotope ratio of lead in airborne particulate matter by ICP-MS

    International Nuclear Information System (INIS)

    Mukai, Hitoshi; Ambe, Yoshinari

    1990-01-01

    ICP-MS was applied to the measurement of stable isotope ratios of lead, which are used as an indicator of the source of lead in airborne particulate matter. For the measurement of lead isotopes ratios, the influences of machine conditions, lead concentration and matrix elements to the precision and accuracy of the measurements were studied. At a scanning mode, dwell time of 40∼160 μs gave the best precision to the isotope ratio measurements; about 0.3 % of R.S.D. for 206 Pb/ 207 Pb and 206 Pb/ 208 Pb, 0.6 % for 206 Pb/ 204 Pb. Precision of the measurement was better at a high concentration of lead in sample solution. The observed value of 206 Pb/ 207 Pb ratio was not affected by the lead concentration, but in the cases of 206 Pb/ 204 Pb and 206 Pb/ 208 Pb, about 1 % of the value changed in the observed ratios with the lead concentration of 100∼500 μg/l. Six matrix elements (Na, K, Ca, Mg, Al, Fe) did not affect the observed isotope ratios up to 200 mg/l. The lead isotope ratios of reference materials {Urban Particulates (NIST) and Vehicle Exhausted Particulates (NIES)} were measured by using two kinds of sample; crude sample and lead-isolated sample from matrix elements by anodic deposition. Both cases gave the same isotope ratio values, therefore, lead isotope ratios in airborne particulate samples can be measured by ICP-MS without any separation of lead from matrix elements. (author)

  2. Early evaluation of hydrogen isotopes separation by V4Cr4Ti-based sorbents at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kulsartov, Timur, E-mail: tima@physics.kz [Institute of Experimental and Theoretical Physics of Kazakh National University, 050038 Almaty (Kazakhstan); Institute of Atomic Energy of National Nuclear Center, 071100 Kurchatov (Kazakhstan); Shestakov, Vladimir; Chikhray, Yevgen; Kenzhina, Inesh; Askerbekov, Saulet [Institute of Experimental and Theoretical Physics of Kazakh National University, 050038 Almaty (Kazakhstan); Gordienko, Yuriy; Ponkratov, Yuriy; Zaurbekova, Zhanna [Institute of Atomic Energy of National Nuclear Center, 071100 Kurchatov (Kazakhstan)

    2016-12-15

    This paper presents the results of experiments on hydrogen isotopes sorption with V4Cr4Ti vanadium alloys from a mixture of hydrogen isotopes. The studies were carried out at temperatures of 353 K, 393 K, 423 K; and pressures of 10{sup 3}–10{sup 4} Pa in gas mixture of hydrogen isotopes. The α-phase domain of V-H (D) system was studied, where the concentration of hydrogen isotopes atoms should not exceed 0.015H (D) atoms per metal atom. The separation parameters were derived for several saturation conditions accordingly to registered time dependences of hydrogen isotopes partial pressure drop. The conclusion was made about the prospects of using vanadium alloys in hydrogen isotopes separation and purification systems.

  3. Do Strontium Isotope Ratios of Animal Bone and Teeth Really Reflect the Isotope Ratios of its birth- and growth-places?

    Science.gov (United States)

    Minami, M.; Goto, A.; Suzuki, K.; Kato, T.; Watanabe, K.; Hasegawa, T.

    2007-12-01

    Strontium enters the human body through the food chain as nutrients pass from bedrock through soil and water to plants and animals. Strontium substitutes for calcium in the hydroxyapatite mineral of skeletal tissue, and is stored there. 87Sr/86Sr ratios in an individual's bone and teeth could directly reflect the isotopic ratios found in the plants and animals that she or he consumed, which reflect the isotope ratios found in the soil and bedrock of that geologic region. Therefore, 87Sr/86Sr ratios of human skeletons could be useful tools for assessing human residential mobility in prehistory, and many studies on them have been often made. In this study, to evaluate whether the 87Sr/86Sr ratio of a bone or teeth really reflects the isotopic ratios of its birth and growth places, several bone and teeth samples were measured for 87Sr/86Sr ratios, compared with 87Sr/86Sr ratios of geological samples in their growth-places. Bone and teeth samples were leached with 5% acetic acid. After drying, samples were ashed in a muffle furnace at 825°C for 8h, and then digested in nitric acid, followed by cation exchange chromatography with 2.4M hydrochloric acid. 87Sr/86Sr ratios were measured using a thermal ionization mass Spectrometer (VG Sector 54) or an inductively coupled plasma mass spectrometer (Finnigan ELEMENT2). A modern boar bone collected at Asuke, Toyota City, Aichi prefecture, Japan showed a 87Sr/86Sr of 0.71001±0.00002 (2 σ), while stream sediments in the Asuke area showed around 0.710 (Asahara et al., 2006). The 87Sr/86Sr ratio of a modern black bass bone collected from Lake Biwa, Shiga prefecture, Japan was 0.71215±0.00002, while those of surface water in Lake Biwa was 0.71233±0.00002. The similar 87Sr/86Sr ratios between bone and its provenance geology could indicate that the 87Sr/86Sr ratios of bones reflect the isotopic ratios of the birth- and growth-places. The more results of modern and fossil skeletons will be shown in our presentation.

  4. Radiation-related retrograde hydrogen isotope and K-Ar exchange in clay minerals

    International Nuclear Information System (INIS)

    Halter, C.; Pagel, M.; Sheppard, S.M.F.; Weber, F.; Clauer, N.

    1987-01-01

    Hydrogen and oxygen isotope studies have been widely applied to characterize the origin of fluids during ore-foaming processes. The primary isotope record, however, may be disturbed by retrograde exchange reactions, thus complicating the interpretation of the data. The susceptibility of minerals to retrograde isotope and chemical exchange is variable, reflecting differences in the mechanism and rate of isotope exchange. Results are presented on deuterium depletion, K/Ar ages and H 2 O + content of illites associated with uranium mineralization from the Athabasca basin (Canada). (author)

  5. Direct uranium isotope ratio analysis of single micrometer-sized glass particles

    International Nuclear Information System (INIS)

    Kappel, Stefanie; Boulyga, Sergei F.; Prohaska, Thomas

    2012-01-01

    We present the application of nanosecond laser ablation (LA) coupled to a ‘Nu Plasma HR’ multi collector inductively coupled plasma mass spectrometer (MC-ICP-MS) for the direct analysis of U isotope ratios in single, 10–20 μm-sized, U-doped glass particles. Method development included studies with respect to (1) external correction of the measured U isotope ratios in glass particles, (2) the applied laser ablation carrier gas (i.e. Ar versus He) and (3) the accurate determination of lower abundant 236 U/ 238 U isotope ratios (i.e. 10 −5 ). In addition, a data processing procedure was developed for evaluation of transient signals, which is of potential use for routine application of the developed method. We demonstrate that the developed method is reliable and well suited for determining U isotope ratios of individual particles. Analyses of twenty-eight S1 glass particles, measured under optimized conditions, yielded average biases of less than 0.6% from the certified values for 234 U/ 238 U and 235 U/ 238 U ratios. Experimental results obtained for 236 U/ 238 U isotope ratios deviated by less than −2.5% from the certified values. Expanded relative total combined standard uncertainties U c (k = 2) of 2.6%, 1.4% and 5.8% were calculated for 234 U/ 238 U, 235 U/ 238 U and 236 U/ 238 U, respectively. - Highlights: ► LA-MC-ICP-MS was fully validated for the direct analysis of individual particles. ► Traceability was established by using an IRMM glass particle reference material. ► Measured U isotope ratios were in agreement with the certified range. ► A comprehensive total combined uncertainty evaluation was performed. ► The analysis of 236 U/ 238 U isotope ratios was improved by using a deceleration filter.

  6. GasBench/isotope ratio mass spectrometry: a carbon isotope approach to detect exogenous CO(2) in sparkling drinks.

    Science.gov (United States)

    Cabañero, Ana I; San-Hipólito, Tamar; Rupérez, Mercedes

    2007-01-01

    A new procedure for the determination of carbon dioxide (CO(2)) (13)C/(12)C isotope ratios, using direct injection into a GasBench/isotope ratio mass spectrometry (GasBench/IRMS) system, has been developed to improve isotopic methods devoted to the study of the authenticity of sparkling drinks. Thirty-nine commercial sparkling drink samples from various origins were analyzed. Values of delta(13)C(cava) ranged from -20.30 per thousand to -23.63 per thousand, when C3 sugar addition was performed for a second alcoholic fermentation. Values of delta(13)C(water) ranged from -5.59 per thousand to -6.87 per thousand in the case of naturally carbonated water or water fortified with gas from the spring, and delta(13)C(water) ranged from -29.36 per thousand to -42.09 per thousand when industrial CO(2) was added. It has been demonstrated that the addition of C4 sugar to semi-sparkling wine (aguja) and industrial CO(2) addition to sparkling wine (cava) or water can be detected. The new procedure has advantages over existing methods in terms of analysis time and sample treatment. In addition, it is the first isotopic method developed that allows (13)C/(12)C determination directly from a liquid sample without previous CO(2) extraction. No significant isotopic fractionation was observed nor any influence by secondary compounds present in the liquid phase. Copyright (c) 2007 John Wiley & Sons, Ltd.

  7. Hydrogen and carbon isotopes of petroleum and related organic matter

    International Nuclear Information System (INIS)

    Yeh, H.W.; Epstein, S.

    1981-01-01

    D/H and 13 C/ 12 C ratios were measured for 114 petroleum samples and for several samples of related organic matter. DeltaD of crude oil ranges from -85 to -181 per thousand except for one distillate (-250 per thousand) from the Kenai gas field; delta 13 C of crude oil ranges from -23.3 to -32.5 per thousand. Variation in deltaD and delta 13 C values of compound-grouped fractions of a crude oil is small, 3 and 1.1 per thousand, respectively, and the difference in deltaD and delta 13 C between oil and coeval wax is slight. Gas fractions are 53 to 70 and 22.6 to 23.2 per thousand depleted in D and 13 C, respectively, relative to the coexisting oil fractions. The deltaD and delta 13 C values of the crude oils appear to be largely determined by the isotopic compositions of their organic precursors. The contribution of terrestrial organic debris to the organic precursors of most marine crude oils may be significant. (author)

  8. Oxygen and hydrogen isotope studies of plutonic granitic rocks

    International Nuclear Information System (INIS)

    Taylor, H.P. Jr.

    1978-01-01

    The primary deltaD values of the biotites and hornblendes in granitic batholiths are remarkably constant at about -50 to -85, identical to the values in regional metamorphic rocks, marine sediments and greenstones, and most weathering products in temperate climates. Therefore the primary water in these igneous rocks is probably not 'juvenile', but is ultimately derived by dehydration and/or partial melting of the lower crust or subducted lithosphere. Most granitic rocks have delta 18 O = +7.0 to +10.0, probably indicating significant involvment of high- 18 O metasedimentary or altered volcanic rocks in the melting process; such an origin is demanded for many other granodiorites and tonalites that have delta 18 O = +10 to +13. Gigantic meteoric-hydrothermal convective circulation systems were established in the epizonal portions of all batholiths, locally producing very low delta 18 O values (particularly in feldspars) during subsolidus exchange. Some granitic plutons in such environments also were emplaced as low- 18 O magmas probably formed by melting or assimilation of hydrothermally altered roof rocks. However, the water/rock ratios were typically low enough that over wide areas the only evidence for meteoric water exchange in the batholiths is given by low D/H ratios (deltaK as low as -180); for example, because of latitudinal isotopic variations in meteoric waters, as one moves north through the Cordilleran batholiths of western North America an increasingly higher proportion of the granitic rocks have deltaD values lower than -120. The lowering of deltaD values commonly corelates with re-setting of K-Ar ages. (Auth.)

  9. Characterization of diesel fuel by chemical separation combined with capillary gas chromatography (GC) isotope ratio mass spectrometry (IRMS).

    Science.gov (United States)

    Harvey, Scott D; Jarman, Kristin H; Moran, James J; Sorensen, Christina M; Wright, Bob W

    2012-09-15

    The purpose of this study was to perform a preliminary investigation of compound-specific isotope analysis (CSIA) of diesel fuels to evaluate whether the technique could distinguish diesel samples from different sources/locations. The ability to differentiate or correlate diesel samples could be valuable for discovering fuel tax evasion schemes or for environmental forensic studies. Two urea adduction-based techniques were used to isolate the n-alkanes from the fuel. Both carbon isotope ratio (δ(13)C) and hydrogen isotope ratio (δD) values for the n-alkanes were then determined by CSIA in each sample. The samples investigated had δ(13)C values that ranged from -30.1‰ to -26.8‰, whereas δD values ranged from -83‰ to -156‰. Plots of δD versus δ(13)C with sample n-alkane points connected in order of increasing carbon number gave well-separated clusters with characteristic shapes for each sample. Principal components analysis (PCA) with δ(13)C, δD, or combined δ(13)C and δD data was applied to extract the maximum information content. PCA scores plots could clearly differentiate the samples, thereby demonstrating the potential of this approach for distinguishing (e.g., fingerprinting) fuel samples using δ(13)C and δD values. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Raman spectroscopic studies of isotopic diatomic molecules and a technique for measuring stable isotope ratios using Raman scattering

    International Nuclear Information System (INIS)

    Harney, R.C.

    1976-01-01

    A method for measuring stable isotope ratios using Raman scattering has been developed. This method consists of simultaneously counting photons scattered out of a high-intensity laser beam by different isotopically-substituted molecules. A number of studies of isotopic diatomic molecules have been made. The Q-branches of the Raman spectra of the isotopic molecules 14 N 15 N and 16 O 18 O were observed at natural abundance in nitrogen and oxygen samples. Comparison of the ratios of the intensities of the Q-branches of the major nitrogen and oxygen isotopic molecules with mass spectrometric determinations of the isotopic compositions yielded scattering cross sections of 14 N 15 N relative to 14 N 14 N and 16 O 18 O relative to 16 O 16 O. These cross section ratios differ from unity, a difference which can be explained by considering nuclear mass effects on the Franck-Condon factors of the molecular transitions. The measured intensities of the 14 N 15 N and 16 O 18 O Q-branches provided the baseline data needed to make the previously-mentioned extrapolation. High-resolution (approximately 0.15 cm -1 ) spectra of the Q-branches of 14 N 14 N and 16 O 16 O yielded a direct determination of α/sub e/ (the difference between the rotational constant in the ground and first excited vibrational states) for these molecules. The measured values are in excellent agreement with those obtained by other means. Complete Raman spectra (pure rotation, rotation-vibration, and high-resolution Q-branch) were obtained on a sample of pure 18 O 18 O. Analysis of this data yielded the molecular parameters: the equilibrium internuclear separation r/sub e/, the moment of inertia I/sub e/, and the energy parameters α/sub e/, B/sub e/, and ΔG/sub 1 / 2 /. These are in good agreement with data obtained by microwave spectroscopy

  11. Carbon and hydrogen isotope fractionation during aerobic biodegradation of quinoline and 3-methylquinoline.

    Science.gov (United States)

    Cui, Mingchao; Zhang, Wenbing; Fang, Jun; Liang, Qianqiong; Liu, Dongxuan

    2017-08-01

    Compound-specific isotope analysis has been used extensively to investigate the biodegradation of various organic pollutants. To date, little isotope fractionation information is available for the biodegradation of quinolinic compounds. In this study, we report on the carbon and hydrogen isotope fractionation during quinoline and 3-methylquinoline aerobic microbial degradation by a Comamonas sp. strain Q10. Degradation of quinoline and 3-methylquinoline was accompanied by isotope fractionation. Large hydrogen and small carbon isotope fractionation was observed for quinoline while minor carbon and hydrogen isotope fractionation effects occurred for 3-methylquinoline. Bulk carbon and hydrogen enrichment factors (ε bulk ) for quinoline biodegradation were -1.2 ± 0.1 and -38 ± 1‰, respectively, while -0.7 ± 0.1 and -5 ± 1‰ for 3-methylquinoline, respectively. This reveals a potential advantage for employing quinoline as the model compound and hydrogen isotope analysis for assessing aerobic biodegradation of quinolinic compounds. The apparent kinetic isotope effects (AKIE C ) values of carbon were 1.008 ± 0.0005 for quinoline and 1.0048 ± 0.0005 for 3-methylquinoline while AKIE H values of hydrogen of 1.264 ± 0.011 for quinoline and 1.0356 ± 0.0103 for 3-methylquinoline were obtained. The combined evaluation of carbon and hydrogen isotope fractionation yields Λ values (Λ = Δδ 2 H/Δδ 13 C ≈ εH bulk /εC bulk ) of 29 ± 2 for quinoline and 8 ± 2 for 3-methylquinoline. The results indicate that the substrate specificity may have a significant influence on the isotope fractionation for the biodegradation of quinolinic compounds. The substrate-specific isotope enrichment factors would be important for assessing the behavior and fate of quinolinic compounds in the environment.

  12. Carbon and hydrogen isotopic effects of stomatal density in Arabidopsis thaliana

    Science.gov (United States)

    Lee, Hyejung; Feakins, Sarah J.; Sternberg, Leonel da S. L.

    2016-04-01

    Stomata are key gateways mediating carbon uptake and water loss from plants. Varied stomatal densities in fossil leaves raise the possibility that isotope effects associated with the openness of exchange may have mediated plant wax biomarker isotopic proxies for paleovegetation and paleoclimate in the geological record. Here we use Arabidopsis thaliana, a widely used model organism, to provide the first controlled tests of stomatal density on carbon and hydrogen isotopic compositions of cuticular waxes. Laboratory grown wildtype and mutants with suppressed and overexpressed stomatal densities allow us to directly test the isotope effects of stomatal densities independent of most other environmental or biological variables. Hydrogen isotope (D/H) measurements of both plant waters and plant wax n-alkanes allow us to directly constrain the isotopic effects of leaf water isotopic enrichment via transpiration and biosynthetic fractionations, which together determine the net fractionation between irrigation water and n-alkane hydrogen isotopic composition. We also measure carbon isotopic fractionations of n-alkanes and bulk leaf tissue associated with different stomatal densities. We find offsets of +15‰ for δD and -3‰ for δ13C for the overexpressed mutant compared to the suppressed mutant. Since the range of stomatal densities expressed is comparable to that found in extant plants and the Cenozoic fossil record, the results allow us to consider the magnitude of isotope effects that may be incurred by these plant adaptive responses. This study highlights the potential of genetic mutants to isolate individual isotope effects and add to our fundamental understanding of how genetics and physiology influence plant biochemicals including plant wax biomarkers.

  13. Isotope dependent, temperature regulated, energy repartitioning in a low-barrier, short-strong hydrogen bonded cluster

    NARCIS (Netherlands)

    Li, X. H.; Oomens, J.; Eyler, J. R.; Moore, D. T.; Iyengar, S. S.

    2010-01-01

    We investigate and analyze the vibrational properties, including hydrogen/deuterium isotope effects, in a fundamental organic hydrogen bonded system using multiple experimental (infrared multiple photon dissociation and argon-tagged action spectroscopy) and computational techniques. We note a

  14. Direct uranium isotope ratio analysis of single micrometer-sized glass particles.

    Science.gov (United States)

    Kappel, Stefanie; Boulyga, Sergei F; Prohaska, Thomas

    2012-11-01

    We present the application of nanosecond laser ablation (LA) coupled to a 'Nu Plasma HR' multi collector inductively coupled plasma mass spectrometer (MC-ICP-MS) for the direct analysis of U isotope ratios in single, 10-20 μm-sized, U-doped glass particles. Method development included studies with respect to (1) external correction of the measured U isotope ratios in glass particles, (2) the applied laser ablation carrier gas (i.e. Ar versus He) and (3) the accurate determination of lower abundant (236)U/(238)U isotope ratios (i.e. 10(-5)). In addition, a data processing procedure was developed for evaluation of transient signals, which is of potential use for routine application of the developed method. We demonstrate that the developed method is reliable and well suited for determining U isotope ratios of individual particles. Analyses of twenty-eight S1 glass particles, measured under optimized conditions, yielded average biases of less than 0.6% from the certified values for (234)U/(238)U and (235)U/(238)U ratios. Experimental results obtained for (236)U/(238)U isotope ratios deviated by less than -2.5% from the certified values. Expanded relative total combined standard uncertainties U(c) (k = 2) of 2.6%, 1.4% and 5.8% were calculated for (234)U/(238)U, (235)U/(238)U and (236)U/(238)U, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Isotope ratio mass spectrometry coupled to liquid and gas chromatography for wine ethanol characterization.

    Science.gov (United States)

    Cabañero, Ana I; Recio, Jose L; Rupérez, Mercedes

    2008-10-01

    Two new procedures for wine ethanol 13C/12C isotope ratio determination, using high-performance liquid chromatography and gas chromatography isotope ratio mass spectrometry (HPLC/IRMS and GC/IRMS), have been developed to improve isotopic methods dedicated to the study of wine authenticity. Parameters influencing separation of ethanol from wine matrix such as column, temperature, mobile phase, flow rates and injection mode were investigated. Twenty-three wine samples from various origins were analyzed for validation of the procedures. The analytical precision was better than 0.15 per thousand, and no significant isotopic fractionation was observed employing both separative techniques coupled to IRMS. No significant differences and a very strong correlation (r = 0.99) were observed between the 13C/12C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The potential advantages of the developed methods over the traditional one are speed (reducing time required from hours to minutes) and simplicity. In addition, these are the first isotopic methods that allow 13C/12C determination directly from a liquid sample with no previous ethanol isolation, overcoming technical difficulties associated with sample treatment.

  16. A Plant-Based Proxy for the Oxygen Isotope Ratio of Atmospheric Water Vapor

    Science.gov (United States)

    Helliker, B.

    2007-12-01

    Atmospheric water vapor is a major component of the global hydrological cycle, but the isotopic balance of vapor is largely unknown. It is shown here that the oxygen isotope ratio of leaf water in the epiphytic Crassulacean acid metabolism (CAM) plant Tillandsia usneoides (Spanish Moss) is controlled by the oxygen isotope ratio of atmospheric water vapor in both field and lab studies. Assuming that the leaf-water isotopic signature (and hence the atmospheric water vapor signature) is recorded in plant organic material, the atmospheric water vapor oxygen isotope ratios for Miami, Florida (USA) were reconstructed for several years from 1878 to 2005 using contemporary and herbarium specimens. T. usneoides ranges from Virginia, USA southwards through the tropics to Argentina, and the CAM epiphytic lifeform is widespread in other species. Therefore, epiphytes may be used to reconstruct the isotope ratio of atmospheric water for spatial scales that span over 60° of latitude and temporal scales that cover the last century of global temperature increase.

  17. Tracing the origin of pollution in French Alpine snow and aerosols using lead isotopic ratios.

    Science.gov (United States)

    Veysseyre, A M; Bollhöfer, A F; Rosman, K J; Ferrari, C P; Boutron, C F

    2001-11-15

    Fresh snow samples collected at 15 remote locations and aerosols collected at one location in the French Alps between November 1998 and April 1999 have been analyzed for Pb concentration and isotopic composition by thermal ionization mass spectrometry. The snow samples contained 19-1300 pg/g of Pb with isotopic ratios 206Pb/207Pb (208Pb/207Pb) of 1.1279-1.1607 (2.3983-2.4302). Airborne Pb concentrations at one sampling site ranged from 0.42 to 6.0 ng/m3 with isotopic ratios of 1.1321-1.1427 (2.4029-2.4160). Air mass trajectory analysis combined with isotopic compositions of potential source regions did not show discernible evidence of the long-range atmospheric transport of pollutants. Isotopic ratios in the Alpine snow samples and thus the free troposphere were generally higher than airborne Pb isotopic ratios in urban France, which coupled with the relatively high Pb concentrations suggested a regional anthropogenic Pb source, probably Italy but possibly Eastern Europe.

  18. Recent progress of hydrogen isotope behavior studies for neutron or heavy ion damaged W

    Energy Technology Data Exchange (ETDEWEB)

    Oya, Yasuhisa, E-mail: syoya@ipc.shizuoka.ac.jp [Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529 (Japan); Hatano, Yuji [University of Toyama, 3190 Gofuku, Toyama 939-8555 (Japan); Shimada, Masashi [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Buchenauer, Dean; Kolasinski, Robert [Sandia National Laboratories, Livermore, CA 94551 (United States); Merrill, Brad [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Kondo, Sosuke; Hinoki, Tatsuya [Kyoto University, Gokasho, Uji 611-0011 (Japan); Alimov, Vladimir Kh. [University of Toyama, 3190 Gofuku, Toyama 939-8555 (Japan)

    2016-12-15

    Highlights: • This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. • Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. • The distribution of defects throughout the sample also changes the shape of TDS spectrum. • Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed. - Abstract: This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. In particular, the desorption temperature shifts higher as the defect concentration increases. In addition, the distribution of defects throughout the sample also changes the shape of TDS spectrum. Even if low energy traps were distributed in the bulk region, the D diffusion toward the surface requires additional time for trapping/detrapping during surface-to-bulk transport, contributing to a shift of desorption peaks toward higher temperatures. It can be said that both of distribution of damage (e.g. hydrogen isotope trapping sites) and their stabilities would have a large impact on desorption. In addition, transmutation effects should be also considered for an actual fusion environment. Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed.

  19. Recent progress of hydrogen isotope behavior studies for neutron or heavy ion damaged W

    International Nuclear Information System (INIS)

    Oya, Yasuhisa; Hatano, Yuji; Shimada, Masashi; Buchenauer, Dean; Kolasinski, Robert; Merrill, Brad; Kondo, Sosuke; Hinoki, Tatsuya; Alimov, Vladimir Kh.

    2016-01-01

    Highlights: • This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. • Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. • The distribution of defects throughout the sample also changes the shape of TDS spectrum. • Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed. - Abstract: This paper reviews recent results pertaining to hydrogen isotope behavior in neutron and heavy ion damaged W. Accumulation of damage in W creates stable trapping sites for hydrogen isotopes, thereby changing the observed desorption behavior. In particular, the desorption temperature shifts higher as the defect concentration increases. In addition, the distribution of defects throughout the sample also changes the shape of TDS spectrum. Even if low energy traps were distributed in the bulk region, the D diffusion toward the surface requires additional time for trapping/detrapping during surface-to-bulk transport, contributing to a shift of desorption peaks toward higher temperatures. It can be said that both of distribution of damage (e.g. hydrogen isotope trapping sites) and their stabilities would have a large impact on desorption. In addition, transmutation effects should be also considered for an actual fusion environment. Experimental results show that production of Re by nuclear reaction of W with neutrons reduces the density of trapping sites, though no remarkable retention enhancement is observed.

  20. Stable carbon and oxygen isotope ratios of malachite from the patinas of ancient bronze objects

    International Nuclear Information System (INIS)

    Smith, A.W.

    1978-01-01

    13 C/ 12 C and 18 O/ 16 O ratios have been measured for 62 samples of the mineral malachite, taken from the patinas of ancient bronze objects (from Britain, Italy, Libya and China), in order to investigate any possible relationship which may exist between the isotope ratios and the burial conditions of the objects. The results indicate that the isotope ratios are controlled by complex factors related to the climate, vegetation and soil type at the burial site. It is suggested that the technique might be used, given favourable circumstances, in the characterization of patinas and as a possible aid in the detection of synthetic patination. (author)

  1. Development and application of liquid chromatography coupled to isotope ratio mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lijun

    2014-02-19

    Stable isotope analysis has found widespread applications in various disciplines such as archaeology, geochemistry, biology, food authenticity, and forensic science. Coupling chromatography to isotope ratio mass spectrometry for compound-specific isotope analysis (CSIA) is a trend, as it provides several advantages over bulk isotope analysis, e.g., relatively simple sample preparation, the ability to measure individual compounds in a complex mixture in one run, and the reduced sample size required for precise isotope analysis. Gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS) has been well-established for compound-specific isotope analysis of volatile organic compounds within the last two decades. However, an interface combining liquid chromatography with isotope ratio mass spectrometry (LC/IRMS) was not commercially available until 2004. The current design of the interface requires using a carbon-free eluent in chromatographic separation. This requirement limits the application of the most frequently used reversed-phase liquid chromatography in CSIA, because the elution strength of water at room temperature is too low to serve as mobile phase in reversed-phase separations. In order to increase the elution strength of water, we propose using high temperature water for chromatographic elution. The polarity of water decreases with an increase of temperature, yielding increased elution strength in reversed-phase columns. Therefore, high temperature water can be used as eluent instead of organic solvent for combining reversed-phase liquid chromatography with isotope ratio mass spectrometry (RPLC/IRMS). Additionally, temperature gradients can replace organic solvent gradients to increase chromatographic resolution. This is very important for LC/IRMS analysis, as precise isotope analysis requires baseline separation of analytes. In this thesis, high-temperature reversed-phase liquid chromatography was coupled to, and for the first time carefully

  2. Development and application of liquid chromatography coupled to isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    Zhang, Lijun

    2014-01-01

    Stable isotope analysis has found widespread applications in various disciplines such as archaeology, geochemistry, biology, food authenticity, and forensic science. Coupling chromatography to isotope ratio mass spectrometry for compound-specific isotope analysis (CSIA) is a trend, as it provides several advantages over bulk isotope analysis, e.g., relatively simple sample preparation, the ability to measure individual compounds in a complex mixture in one run, and the reduced sample size required for precise isotope analysis. Gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS) has been well-established for compound-specific isotope analysis of volatile organic compounds within the last two decades. However, an interface combining liquid chromatography with isotope ratio mass spectrometry (LC/IRMS) was not commercially available until 2004. The current design of the interface requires using a carbon-free eluent in chromatographic separation. This requirement limits the application of the most frequently used reversed-phase liquid chromatography in CSIA, because the elution strength of water at room temperature is too low to serve as mobile phase in reversed-phase separations. In order to increase the elution strength of water, we propose using high temperature water for chromatographic elution. The polarity of water decreases with an increase of temperature, yielding increased elution strength in reversed-phase columns. Therefore, high temperature water can be used as eluent instead of organic solvent for combining reversed-phase liquid chromatography with isotope ratio mass spectrometry (RPLC/IRMS). Additionally, temperature gradients can replace organic solvent gradients to increase chromatographic resolution. This is very important for LC/IRMS analysis, as precise isotope analysis requires baseline separation of analytes. In this thesis, high-temperature reversed-phase liquid chromatography was coupled to, and for the first time carefully

  3. Isotopic-spectral determination of hydrogen, nitrogen, oxygen and carbon in semiconductor materials

    International Nuclear Information System (INIS)

    Dudich, G.K.; Eremeev, V.A.; Li, V.N.; Nemets, V.M.

    1981-01-01

    Techniques of low-temperature isotopic-spectral determination of impurities of hydrogen, nitrogen, oxygen and carbon in semiconductor materials Bi, Ge, Pb tellurides are developed. The techniques include selection into special vessel with the known volume (exchanger) of sample analyzed, dosed introduction into exchanger of rare isotope of the element determined ( 2 H, 15 N, 18 O, 13 C) in the form of isotope-containing gas, balancing of the determined element isotopes in the system sample-isotope, containing gas, spectroscopic, determination of its isotope composition in gaseous phase of the system and calculation of the amount of the element determined in the sample. The lower boundaries of the amounts determined constitute 10 -7 , 10 -7 , 10 -6 and 10 -5 mass % respectively when sample of 20 g are used [ru

  4. Studies about interaction of hydrogen isotopes with metals and intermetallic compounds

    International Nuclear Information System (INIS)

    Vasut, F.; Anisoara, P.; Zamfirache, M.

    2003-01-01

    Hydrogen is a non-toxic but highly inflammable gas. Compared to other inflammable gases, its range of inflammability in air is much broader (4-74.5%) but it also vaporizes much more easily. Handling of hydrogen in form of hydrides enhances safety. The interaction of hydrogen with metals and intermetallic compounds is a major field within physical chemistry. Using hydride-forming metals and intermetallic compounds, for example, recovery, purification and storage of heavy isotopes in tritium containing system can solve many problems arising in the nuclear-fuel cycle. The paper presents the thermodynamics and the kinetics between hydrogen and metal or intermetallic compounds. (author)

  5. Mechanistic study of the isotopic-exchange reaction between gaseous hydrogen and palladium hydride powder

    International Nuclear Information System (INIS)

    Outka, D.A.; Foltz, G.W.

    1991-01-01

    A detailed mechanism for the isotopic-exchange reaction between gaseous hydrogen and solid palladium hydride is developed which extends previous model for this reaction by specifically including surface reactions. The modeling indicates that there are two surface-related processes that contribute to the overall rate of exchange: the desorption of hydrogen from the surface and the exchange between surface hydrogen and bulk hydrogen. This conclusion is based upon measurements examining the effect of small concentrations of carbon monoxide were helpful in elucidating the mechanism. Carbon monoxide reversibly inhibits certain steps in the exchange; this slows the overall rate of exchange and changes the distribution of products from the reactor

  6. Isotope ratio monitoring LC/MS (IRM-LC/MS): new applications

    International Nuclear Information System (INIS)

    Juchelka, D; Hilkert, A.; Krummen, M.

    2005-01-01

    With the introduction of compound specific isotope analysis by isotope ratio monitoring GC/ MS (IRM-GC/MS) the immediate demand for similar applications using HPLC was created. Many compounds of biological, medical, pharmaceutical and environmental interest are not volatile or too polar. Consequently, they cannot be directly analyzed by gas chromatography. In IRM-GC/MS the carrier is helium, which does not interfere with the essential combust ion step prior to isotope ratio mass spectrometry (IRMS). In opposite the LC mobile phase has inhibited a similar direct conversion up to now. All earlier IRM-LC/MS approaches were based on the removal of the liquid phase prior to combustion risking fractionation of the isotope ratios of the eluted compounds. To avoid such restrictions we developed a new continuous flow concept for the coupling of an HPLC system to the isotope ratio MS for 13 C/ 12C isotope ratio analysis. In the Finnigan LC IsoLink, the liquid phase is not removed from the sample prior to oxidation. The sample is oxidized still in the mobile phase followed by on-line separation of the CO 2 from the liquid phase and transfer into the isotope ratio MS. Therefore, this strategy is based on water and inorganic buffers as mobile phase. The new approach opens up a whole new world in the application of gas isotope ratio mass spectrometry. The 13 C/ 12 C ratio s of organic acids, amino acids, carbohydrates and nucleotides can now be measured. These components typically within a complex matrix are separated by liquid chromatography followed by on-line determination of the isotope ratios. The draw backs of using derivatization and off-line preparation procedures can now be over come. This new technique allow s studying biochemical cycles, running tracer experiments and determining the origin of components. Applications from different scientific areas such as biogeochemistry, molecular biology, and pharmacy as well as authenticity control o f foods will be presented

  7. Assessment of primary production in a eutrophic lake from carbon and nitrogen isotope ratios of a carnivorous fish

    International Nuclear Information System (INIS)

    Yoshioka, Takahito

    1991-01-01

    The carbon and nitrogen isotope ratios of Hypomesus transpacificus (a pond smelt) in a eutrophic lake, Lake Suwa, were measured from April to September in 1986 and 1987. The differences in the isotope ratios between these two years were observed. The stable isotopes were transferred from phytoplankton to zooplankton and pond smelt, associated with organic matters. Therefore, the difference in the isotope ratios in two years seemed to reflect the differences of the proceeding of primary production. It was suggested that the carbon and nitrogen isotope ratios of animal, whose trophic level is far from primary producer, can be the qualitative indicators for assessing the primary production in a lake ecosystem. (author)

  8. Assessment for ion beam analysis methods about hydrogen isotope in hydrogen storaged metal

    International Nuclear Information System (INIS)

    Ding Wei; Long Xinggui; Shi Liqun

    2006-01-01

    In this paper, experimental arrangements of measuring hydrogen isotope concentration and distribution in metal hydride with ion beam analysis methods were reported, and the advantage and disadvantage of different methods were analyzed too. Experiment results show that it can get abundant information and accurate value by these ways. It can get an accurate value since it's the Rutherford cross-section, and the Mylar film used in the experiment is thin enough for H, D and T distinguishing each other while using ERD analysis method with 6.0 MeV O ion beam to proceed this work, but the disadvantage of this method is that the sample preparing is more difficult, and the analysis depth is lower. It could get the distribution information of H, D and T and the analysis depth is about 3.0 μm while using ERD analysis method with 7.4 MeV 4 He ion beam, but the disadvantage is that the spectra of H, D and T overlap each other, which makes a big error in simulated calculation. If using PBS method with 3.0 MeV proton, the analysis depth is deeper, but it couldn't get the H distribution information. (authors)

  9. Absolute measurement of the isotopic ratio of a water sample with very low deuterium content

    International Nuclear Information System (INIS)

    Hagemann, R.; Nief, G.; Roth, E.

    1968-01-01

    The presence of H 3+ ions which are indistinguishable from HD + ions presents the principal difficulty encountered in the measurement of isotopic ratios of water samples with very low deuterium contents using a mass spectrometer. Thus, when the sample contains no deuterium, the mass spectrometer does not indicate zero. By producing, in situ, from the sample to be measured, water vapor with an isotopic ratio very close to zero using a small distilling column, this difficulty is overcome. This column, its operating parameters, as well as the way in which the measurements are made are described. An arrangement is employed in which the isotopic ratios can be measured with a sensitivity better than 0.01 x 10 -6 . The method is applied to the determination of the isotopic ratios of three low deuterium content water samples. The results obtained permit one to assign to the sample with the lowest deuterium content an absolute value equal to 1.71 ± 0.03 ppm. This water sample is a primary standard from which is determined the isotopic ratio of a natural water sample which serves as the laboratory standard. (author) [fr

  10. Determination of carbon isotope ratios in plant starch via selective enzymatic hydrolysis

    International Nuclear Information System (INIS)

    Schimmelmann, A.; DeNiro, M.J.

    1983-01-01

    A method for the determination of the carbon isotope ratios in bipolymers hydrolyzed by enzymatic action consists of separating the monomer by passage through a dialysis membrane and then combusting the monomer prior to isotopic analysis. The method is described for application to the analysis of starch, but it should find application for polymers than can be degraded quantitatively to monomers and/or oligomers using specific hydrolytic enzymes

  11. Direct isotope ratio measurement of uranium metal by emission spectrometry on a laser-produced plasma

    International Nuclear Information System (INIS)

    Pietsch, W.; Petit, A.; Briand, A.

    1995-01-01

    The method of Optical Emission Spectrometry on a Laser-Produced Plasma (OES/LPP) at reduced pressure has been studied for the determination of the uranium isotope ratio ( 235 U/ 238 U). Spectral profiles of the investigated transition U-II 424.437 nm show the possibility to obtain an isotopic spectral resolution in a laser-produced plasma under exactly defined experimental conditions. Spectroscopic data and results are presented. (author)

  12. Evaluating the reliability of uranium concentration and isotope ratio measurements via an interlaboratory comparison program

    International Nuclear Information System (INIS)

    Oliveira Junior, Olivio Pereira de; Oliveira, Inez Cristina de; Pereira, Marcia Regina; Tanabe, Eduardo

    2009-01-01

    The nuclear fuel cycle is a strategic area for the Brazilian development because it is associated with the generation of electricity needed to boost the country economy. Uranium is one the chemical elements in this cycle and its concentration and isotope composition must be accurately known. In this present work, the reliability of the uranium concentration and isotope ratio measurements carried out at the CTMSP analytical laboratories is evaluated by the results obtained in an international interlaboratory comparison program. (author)

  13. Determination of isotope ratio of elements by mass distribution in molecules of varied chemical compounds

    International Nuclear Information System (INIS)

    Gladkikh, I.S.; Babichev, A.P.

    1999-01-01

    The procedure and program for calculation of isotope ratio of elements involving in the compound being studied using data of mass spectrometry were elaborated. The methods developed for the O 2 , SiH 4 , Cd(CH 3 ) 2 molecules were demonstrated for the illustration. The results of calculation provide support for the efficiency of the program and satisfactory reliability of the results during calculation of the isotope and complex compound concentrations. The program may be used for the estimation of the degree of nonequilibrium isotope distributions, it may indicate on the errors of the mass spectroscopy results [ru

  14. Isotope ratio analysis by a combination of element analyzer and mass spectrometer

    International Nuclear Information System (INIS)

    Pichlmayer, F.

    1987-06-01

    The use of stable isotope ratios of carbon, nitrogen and sulfur as analytical tool in many fields of research is of growing interest. A method has therefore been developed, consisting in essential of coupling an Elemental Analyzer with an Isotope Mass Spectrometer, which enables the gas preparation of carbon dioxide, nitrogen and sulfur dioxide from any solid or liquid sample in a fast and easy way. Results of carbon isotope measurements in food analysis are presented, whereat it is possible to check origin and treatment of sugar, oils, fats, mineral waters, spirituous liquors etc. and to detect adulterations as well. Also applications in the field of environmental research are given. (Author)

  15. Low-temperature diffusion of hydrogen isotopes in tantalum

    International Nuclear Information System (INIS)

    Peichl, R.; Ziegler, P.; Weidinger, A.

    1987-01-01

    The mobility of hydrogen and deuterium in tantalum is investigated in the temperature range between 4.2 and 30 K. On the time scale of the present experiment (25 μs) we find that hydrogen begins to move above 15 K whereas deuterium remains immobile at least up to 30 K. Since the interpretation of the data depends critically on the exact hydrogen configurations a major part of the paper is devoted to this problem. We suggest that hydrogen can exist in fairly localized or more extended states depending on the local homogeneity of the crystal. (orig.)

  16. Carbon Isotope Measurements of Experimentally-Derived Hydrothermal Mineral-Catalyzed Organic Products by Pyrolysis-Isotope Ratio Mass Spectrometry

    Science.gov (United States)

    Socki, Richard A.; Fu, Qi; Niles, Paul B.

    2011-01-01

    We report results of experiments to measure the C isotope composition of mineral catalyzed organic compounds derived from high temperature and high pressure synthesis. These experiments make use of an innovative pyrolysis technique designed to extract and measure C isotopes. To date, our experiments have focused on the pyrolysis and C isotope ratio measurements of low-molecular weight intermediary hydrocarbons (organic acids and alcohols) and serve as a proof of concept for making C and H isotope measurements on more complicated mixtures of solid-phase hydrocarbons and intermediary products produced during high temperature and high pressure synthesis on mineral-catalyzed surfaces. The impetus for this work stems from recently reported observations of methane detected within the Martian atmosphere [1-4], coupled with evidence showing extensive water-rock interaction during Martian history [5-7]. Methane production on Mars could be the result of synthesis by mineral surface-catalyzed reduction of CO2 and/or CO by Fischer-Tropsch Type (FTT) reactions during serpentization reactions [8,9]. Others have conducted experimental studies to show that FTT reactions are plausible mechanisms for low-molecular weight hydrocarbon formation in hydrothermal systems at mid-ocean ridges [10-12]. Further, recent experiments by Fu et al. [13] focus on examining detailed C isotope measurements of hydrocarbons produced by surface-catalyzed mineral reactions. Work described in this paper details the experimental techniques used to measure intermediary organic reaction products (alcohols and organic acids).

  17. Studies of isotopic defined hydrogen beams scattering from Pd single-crystal surfaces

    International Nuclear Information System (INIS)

    Varlam, Mihai; Steflea, Dumitru

    1999-01-01

    An experimental investigation of hydrogen isotopes interaction with Pd single-crystal surfaces has been carried out using molecular beam technique. The energy dependence of the sticking probability and its relation with the trapping probability into the precursor state is studied by integrating the scattered angular distribution of hydrogen isotopic defined beams from Pd (111) surfaces in the 40 - 400 K surface temperature range. The dependence has been evaluated by defining hydrogen molecular beams with different isotopic concentration - from the natural one until 5% D/(D + H) and different incident energies and directed onto a single - crystal Pd (111) surface. In the paper, we report the experimental results and some considerations related to them. (authors)

  18. Use of nuclear reactions and ion channeling techniques for depth profiling hydrogen isotopes in solids

    International Nuclear Information System (INIS)

    Appleton, B.R.

    1979-01-01

    Hydrogen has always played a preeminent role in materials science because it so readily alters the physical and chemical properties of materials. However, it is often difficult to determine its role because it is one of the most elusive constituents to detect. More recently hydrogen detection has become necessary in numerous energy-related fields. In fusion energy one must understand plasma particle (hydrogen isotope) recycling, trapping and reemission, as well as the effects of hydrogen on the materials properties of first wall structures in plasma devices (i.e., hydrogen embrittlement, sputtering, blistering, etc.). In geology the presence of hydrogen in various forms alters the mechanical properties of many minerals in the earth's crust and enters directly into studies of tectonic processes. Evaluation of hydrogen in moon rocks increases our understanding of solar wind activity. In solar energy, hydrogen plays an important role in amorphous silicon used in fabricating solar cells. Detection of hydrogen is clearly important in the fossil fuel area. Many of the conventional elemental analysis techniques are not directly applicable to hydrogen determination and others can only detect hydrogen when it is in combination with other elements (i.e., H 2 O, OH, etc.). In this paper we discuss the use of ion beam techniques for obtaining quantitative depth information on hydrogen in materials and discuss the application of these techniques to several problems important in some of the areas mentioned

  19. MEASUREMENTS OF COSMIC-RAY HYDROGEN AND HELIUM ISOTOPES WITH THE PAMELA EXPERIMENT

    International Nuclear Information System (INIS)

    Adriani, O.; Bongi, M.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Bruno, A.; Boezio, M.; Bonvicini, V.; Formato, V.; Bogomolov, E. A.; Bottai, S.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Santis, C. De; Castellini, G.; Donato, C. De; Simone, N. De; Felice, V. Di

    2016-01-01

    The cosmic-ray hydrogen and helium ( 1 H, 2 H, 3 He, 4 He) isotopic composition has been measured with the satellite-borne experiment PAMELA, which was launched into low-Earth orbit on board the Resurs-DK1 satellite on 2006 June 15. The rare isotopes 2 H and 3 He in cosmic rays are believed to originate mainly from the interaction of high-energy protons and helium with the galactic interstellar medium. The isotopic composition was measured between 100 and 1100 MeV/n for hydrogen and between 100 and 1400 MeV/n for helium isotopes using two different detector systems over the 23rd solar minimum from 2006 July to 2007 December

  20. MEASUREMENTS OF COSMIC-RAY HYDROGEN AND HELIUM ISOTOPES WITH THE PAMELA EXPERIMENT

    Energy Technology Data Exchange (ETDEWEB)

    Adriani, O.; Bongi, M. [University of Florence, Department of Physics, I-50019 Sesto Fiorentino, Florence (Italy); Barbarino, G. C. [University of Naples “Federico II,” Department of Physics, I-80126 Naples (Italy); Bazilevskaya, G. A. [Lebedev Physical Institute, RU-119991, Moscow (Russian Federation); Bellotti, R.; Bruno, A. [University of Bari, Department of Physics, I-70126 Bari (Italy); Boezio, M.; Bonvicini, V.; Formato, V. [INFN, Sezione di Trieste, I-34149 Trieste (Italy); Bogomolov, E. A. [Ioffe Physical Technical Institute, RU-194021 St. Petersburg (Russian Federation); Bottai, S. [INFN, Sezione di Florence, I-50019 Sesto Fiorentino, Florence (Italy); Cafagna, F. [INFN, Sezione di Bari, I-70126 Bari (Italy); Campana, D. [INFN, Sezione di Naples, I-80126 Naples (Italy); Carlson, P. [KTH, Department of Physics, and the Oskar Klein Centre for Cosmoparticle Physics, AlbaNova University Centre, SE-10691 Stockholm (Sweden); Casolino, M.; Santis, C. De [University of Rome “Tor Vergata,” Department of Physics, I-00133 Rome (Italy); Castellini, G. [IFAC, I-50019 Sesto Fiorentino, Florence (Italy); Donato, C. De; Simone, N. De; Felice, V. Di [INFN, Sezione di Rome “Tor Vergata,” I-00133 Rome (Italy); and others

    2016-02-10

    The cosmic-ray hydrogen and helium ({sup 1}H, {sup 2}H, {sup 3}He, {sup 4}He) isotopic composition has been measured with the satellite-borne experiment PAMELA, which was launched into low-Earth orbit on board the Resurs-DK1 satellite on 2006 June 15. The rare isotopes {sup 2}H and {sup 3}He in cosmic rays are believed to originate mainly from the interaction of high-energy protons and helium with the galactic interstellar medium. The isotopic composition was measured between 100 and 1100 MeV/n for hydrogen and between 100 and 1400 MeV/n for helium isotopes using two different detector systems over the 23rd solar minimum from 2006 July to 2007 December.

  1. Hydrogen isotopic messages in sulfate reducer lipids: a recorder of metabolic state?

    Science.gov (United States)

    Bradley, A. S.; Leavitt, W.; Zhou, A.; Cobban, A.; Suess, M.

    2017-12-01

    A significant range in microbial lipid 2H/1H ratios is observed in modern marine sediments. The magnitude of hydrogen isotope fractionation between microbial lipids and growth water (2ɛlipid-H2O) is hypothesized to relate to the central carbon and energy metabolism. These observations raise the possibility for culture independent identification of the dominant metabolic pathways operating in a given environment [Zhang et al. 2009]. One such metabolism we aim to track is microbial sulfate reduction. To-date, sulfate reducing bacteria have been observed to produce lipids that are depleted in fatty acid H-isotope composition, relative to growth water (2ɛlipid-H2O -50 to -175 ‰) [Campbell et al. 2009; Dawson et al. 2015; Osburn et al.], with recent work demonstrating a systematic relationship between lipid/water fractionation and growth rate when the electron-bifurcating NAD(P)(H) transhydrogenase (ebTH) activity was disrupted and the available electron requires the ebTH [Leavitt et al. 2016. Front Microbio]. Recent work in aerobic methylotrophs [Bradley et al. 2014. AGU] implicates non-bifurcating NAD(P)(H) transhydrogenase activity is a critical control on 2ɛlipid-H2O. This suggests a specific mechanism to control the range in fractionation is the ratio of intracellular NADPH/NADH/NADP/NAD in aerobes and perhaps the same in anaerobes with some consideration for FADH/FAD. Fundamentally this implies 2ɛlipid-H2O records intracellular redox state. In our sulfate reducer model system Desulfovibrio alaskensis strain G20 a key component of energy metabolism is the activity of ebTH. Nonetheless, this strain contains two independent copies of the genes, only one of which generates a distinctive isotopic phenotype [Leavitt et al. 2016. Front Microbio]. In this study we extend the recent work in G20 to continuous culture experiments comparing WT to nfnAB-2 transposon interruptions, where both organisms are cultivated continuously, at the rate of the slower growing mutant

  2. Charge exchange of excited mesic atoms of hydrogen isotopes in triple collisions with molecules

    International Nuclear Information System (INIS)

    Men'shikov, L.I.; Ponomarev, L.I.

    1985-01-01

    At high densities of deuterium-tritium mixture the probability for the occurrence of the isotope-exchange reaction (dμ)/sub n/+t → d+(tμ)/sub n/ from the excited states of n mesic atoms of deuterium is high in the triple collisions of mesic atoms with the molecules of hydrogen isotopes. This reaction should be taken into account in describing the kinetics of muon catalysis

  3. Effectiveness of different pre-treatments in recovering pre-burial isotopic ratios of charred plants.

    Science.gov (United States)

    Brinkkemper, O; Braadbaart, F; van Os, B; van Hoesel, A; van Brussel, A A N; Fernandes, R

    2018-02-15

    Isotopic analysis of archaeological charred plant remains offers useful archaeological information. However, adequate sample pre-treatment protocols may be necessary to provide a contamination-free isotopic signal while limiting sample loss and achieving a high throughput. Under these constraints, research was undertaken to compare the performance of different pre-treatment protocols. Charred archaeological plant material was selected for isotopic analysis (δ 13 C and δ 15 N values) by isotope ratio mass spectrometry from a variety of plant species, time periods and soil conditions. Preservation conditions and the effectiveness of cleaning protocols were assessed through Fourier transform infrared spectroscopy and X-ray fluorescence (XRF) spectrometry. An acid-base-acid protocol, successfully employed in radiocarbon dating, was used to define a contamination-free isotopic reference. Acid-base-acid isotopic measurements were compared with those obtained from untreated material and an acid-only protocol. The isotopic signals of untreated material and the acid-only protocol typically did not differ more than 1‰ from those of the acid-base-acid reference. There were no significant isotopic offsets between acid-base-acid and acid-only or untreated samples. Sample losses in the acid-base-acid protocol were on average 50 ± 17% (maximum = 98.4%). Elemental XRF measurements showed promising results in the detection of more contaminated samples albeit with a high rate of false positives. For the large range of preservation conditions described in the study, untreated charred plant samples, water cleaned of sediments, provide reliable stable isotope ratios of carbon and nitrogen. The use of pre-treatments may be necessary under different preservation conditions or more conservative measurement uncertainties should be reported. Copyright © 2017 John Wiley & Sons, Ltd.

  4. On dewetting dynamics of solid films of hydrogen isotopes and its influence on tritium β spectroscopy

    International Nuclear Information System (INIS)

    Fleischmann, L.; Bonn, J.; Bornschein, B.; Otten, E.W.; Przyrembel, M.; Weinheimer, Ch.

    2000-01-01

    The dewetting dynamics of solid films of hydrogen isotopes, quench-condensed on a graphite substrate, was measured at various temperatures below desorption by observing the stray light from the film. A schematic model describing the dewetting process by surface diffusion is presented, which agrees qualitatively with our data. The activation energies of different hydrogen isotopes for surface diffusion were determined. The time constant for dewetting of a quench-condensed T 2 film at the working temperature of 1.86 K of the mainz neutrino mass experiment was extrapolated. (orig.)

  5. New method for the hydrogen isotope exchange reaction in a hydrophobic catalyst bed

    International Nuclear Information System (INIS)

    Asakura, Y.; Kikuchi, M.; Yusa, H.

    1982-01-01

    To improve the isotope exchange reaction efficiency between water and hydrogen, a new reactor in which water mists and hydrogen gas react cocurrently was studied. To apply this to the enrichment of tritium in heavy water, a dual temperature isotope exchange reactor which is composed of cocurrent low temperature reactors and the usual countercurrent high temperature reactor was proposed and analyzed using a McCabe-Thiele diagram. By utilizing cocurrent reactors, in combination, the necessary catalyst volume can be reduced to one-tenth as compared with the usual countercurrent low temperature reactor. 17 refs

  6. A new type separation column for the water-hydrogen isotope catalytic exchange process

    International Nuclear Information System (INIS)

    Fedorchenko, O.A.; Alekseev, I.A.; Trenin, V.D.

    2001-01-01

    The catalytic water/hydrogen isotope exchange process is by right considered the most attractive for the solution a number of urgent problems of hydrogen isotope separation. A new type exchange reaction column is described and studied in details by computer simulation and with the help of McCabe-Thiele diagrams. It is shown that the new column in comparison with a traditional one needs less catalyst quantity and a smaller diameter for the solving of the same separation tasks. Generalized calculation data are presented in graphical form

  7. The puzzle of the CNO isotope ratios in asymptotic giant branch carbon stars

    Science.gov (United States)

    Abia, C.; Hedrosa, R. P.; Domínguez, I.; Straniero, O.

    2017-03-01

    Context. The abundance ratios of the main isotopes of carbon, nitrogen and oxygen are modified by the CNO-cycle in the stellar interiors. When the different dredge-up events mix the burning material with the envelope, valuable information on the nucleosynthesis and mixing processes can be extracted by measuring these isotope ratios. Aims: Previous determinations of the oxygen isotopic ratios in asymptotic giant branch (AGB) carbon stars were at odds with the existing theoretical predictions. We aim to redetermine the oxygen ratios in these stars using new spectral analysis tools and further develop discussions on the carbon and nitrogen isotopic ratios in order to elucidate this problem. Methods: Oxygen isotopic ratios were derived from spectra in the K-band in a sample of galactic AGB carbon stars of different spectral types and near solar metallicity. Synthetic spectra calculated in local thermodynamic equillibrium (LTE) with spherical carbon-rich atmosphere models and updated molecular line lists were used. The CNO isotope ratios derived in a homogeneous way, were compared with theoretical predictions for low-mass (1.5-3 M⊙) AGB stars computed with the FUNS code assuming extra mixing both during the RGB and AGB phases. Results: For most of the stars the 16O/17O/18O ratios derived are in good agreement with theoretical predictions confirming that, for AGB stars, are established using the values reached after the first dredge-up (FDU) according to the initial stellar mass. This fact, as far as the oxygen isotopic ratios are concerned, leaves little space for the operation of any extra mixing mechanism during the AGB phase. Nevertheless, for a few stars with large 16O/17O/18O, the operation of such a mechanism might be required, although their observed 12C/13C and 14N/15N ratios would be difficult to reconcile within this scenario. Furthermore, J-type stars tend to have lower 16O/17O ratios than the normal carbon stars, as already indicated in previous studies

  8. Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS)--part 1: instrument validation of the DELTAplusXP IRMS for bulk nitrogen isotope ratio measurements.

    Science.gov (United States)

    Benson, Sarah J; Lennard, Christopher J; Hill, David M; Maynard, Philip; Roux, Claude

    2010-01-01

    A significant amount of research has been conducted into the use of stable isotopes to assist in determining the origin of various materials. The research conducted in the forensic field shows the potential of isotope ratio mass spectrometry (IRMS) to provide a level of discrimination not achievable utilizing traditional forensic techniques. Despite the research there have been few, if any, publications addressing the validation and measurement uncertainty of the technique for forensic applications. This study, the first in a planned series, presents validation data for the measurement of bulk nitrogen isotope ratios in ammonium nitrate (AN) using the DELTA(plus)XP (Thermo Finnigan) IRMS instrument equipped with a ConFlo III interface and FlashEA 1112 elemental analyzer (EA). Appropriate laboratory standards, analytical methods and correction calculations were developed and evaluated. A validation protocol was developed in line with the guidelines provided by the National Association of Testing Authorities, Australia (NATA). Performance characteristics including: accuracy, precision/repeatability, reproducibility/ruggedness, robustness, linear range, and measurement uncertainty were evaluated for the measurement of nitrogen isotope ratios in AN. AN (99.5%) and ammonium thiocyanate (99.99+%) were determined to be the most suitable laboratory standards and were calibrated against international standards (certified reference materials). All performance characteristics were within an acceptable range when potential uncertainties, including the manufacturer's uncertainty of the technique and standards, were taken into account. The experiments described in this article could be used as a model for validation of other instruments for similar purposes. Later studies in this series will address the more general issue of demonstrating that the IRMS technique is scientifically sound and fit-for-purpose in the forensic explosives analysis field.

  9. Effect of coexistent hydrogen isotopes on tracer diffusion of tritium in alpha phase of group-V metal-hydrogen systems

    International Nuclear Information System (INIS)

    Sakamoto, Kan; Hashizume, Kenichi; Sugisaki, Masayasu

    2009-01-01

    Tracer diffusion coefficients of tritium in the alpha phase of group-V metal-hydrogen systems, α-MH(D)xTy (M=V and Ta; x>>y), were measured in order to clarify the effects of coexistent hydrogen isotopes on the tritium diffusion behavior. The hydrogen concentration dependence of such behavior and the effects of the coexistent hydrogen isotopes (protium and deuterium) were determined. The results obtained in the present (for V and Ta) and previous (for Nb) studies revealed that tritium diffusion was definitely dependent on hydrogen concentration but was not so sensitive to the kind of coexistent hydrogen isotopes. By summarizing those data, it was found that the hydrogen concentration dependence of the tracer diffusion coefficient of tritium in the alpha phase of group-V metals could be roughly expressed by a single empirical curve. (author)

  10. Nicotine, acetanilide and urea multi-level2H-,13C- and15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry

    Science.gov (United States)

    Schimmelmann, A.; Albertino, A.; Sauer, P.E.; Qi, H.; Molinie, R.; Mesnard, F.

    2009-01-01

    Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the S values of these reference materials should bracket the isotopic range of samples with unknown S values. While the practice of analyzing two isotopically distinct reference materials is common for water (VSMOW-SLAP) and carbonates (NBS 19 and L-SVEC), the lack of widely available organic reference materials with distinct isotopic composition has hindered the practice when analyzing organic materials by elemental analysis/isotope ratio mass spectrometry (EA-IRMS). At present only L-glutamic acids USGS40 and USGS41 satisfy these requirements for ??13C and ??13N, with the limitation that L-glutamic acid is not suitable for analysis by gas chromatography (GC). We describe the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i.e. continuous flow) hydrogen reductive gas chromatography-isotope ratio mass-spectrometry (GC-IRMS), (ii) five nicotines for oxidative C, N gas chromatography-combustion-isotope ratio mass-spectrometry (GC-C-IRMS, or GC-IRMS), and (iii) also three acetanilide and three urea reference materials for on-line oxidative EA-IRMS for C and N. Isotopic off-line calibration against international stable isotope measurement standards at Indiana University adhered to the 'principle of identical treatment'. The new reference materials cover the following isotopic ranges: ??2Hnicotine -162 to -45%o, ??13Cnicotine -30.05 to +7.72%, ?? 15Nnicotine -6.03 to +33.62%; ??15N acetanilide +1-18 to +40.57%; ??13Curea -34.13 to +11.71%, ??15Nurea +0.26 to +40.61% (recommended ?? values refer to calibration with NBS 19, L-SVEC, IAEA-N-1, and IAEA-N-2). Nicotines fill a gap as the first organic nitrogen stable isotope reference materials for GC-IRMS that are available with different ??13N

  11. Nicotine, acetanilide and urea multi-level 2H-, 13C- and 15N-abundance reference materials for continuous-flow isotope ratio mass spectrometry.

    Science.gov (United States)

    Schimmelmann, Arndt; Albertino, Andrea; Sauer, Peter E; Qi, Haiping; Molinie, Roland; Mesnard, François

    2009-11-01

    Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the delta values of these reference materials should bracket the isotopic range of samples with unknown delta values. While the practice of analyzing two isotopically distinct reference materials is common for water (VSMOW-SLAP) and carbonates (NBS 19 and L-SVEC), the lack of widely available organic reference materials with distinct isotopic composition has hindered the practice when analyzing organic materials by elemental analysis/isotope ratio mass spectrometry (EA-IRMS). At present only L-glutamic acids USGS40 and USGS41 satisfy these requirements for delta13C and delta15N, with the limitation that L-glutamic acid is not suitable for analysis by gas chromatography (GC). We describe the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i.e. continuous flow) hydrogen reductive gas chromatography-isotope ratio mass-spectrometry (GC-IRMS), (ii) five nicotines for oxidative C, N gas chromatography-combustion-isotope ratio mass-spectrometry (GC-C-IRMS, or GC-IRMS), and (iii) also three acetanilide and three urea reference materials for on-line oxidative EA-IRMS for C and N. Isotopic off-line calibration against international stable isotope measurement standards at Indiana University adhered to the 'principle of identical treatment'. The new reference materials cover the following isotopic ranges: delta2H(nicotine) -162 to -45 per thousand, delta13C(nicotine) -30.05 to +7.72 per thousand, delta15N(nicotine) -6.03 to +33.62 per thousand; delta15N(acetanilide) +1.18 to +40.57 per thousand; delta13C(urea) -34.13 to +11.71 per thousand, delta15N(urea) +0.26 to +40.61 per thousand (recommended delta values refer to calibration with NBS 19, L-SVEC, IAEA-N-1, and IAEA-N-2). Nicotines fill a gap as

  12. A continuous flow isotope ratio mass spectrometry method for high precision determination of dissolved gas ratios and isotopic composition

    DEFF Research Database (Denmark)

    Charoenpong, C. N.; Bristow, L. A.; Altabet, M. A.

    2014-01-01

    ratio mass spectrometer (IRMS). A continuous flow of He carrier gas completely degasses the sample, and passes through the preparation and purification system before entering the IRMS for analysis. The use of this continuous He carrier permits short analysis times (less than 8 min per sample......) as compared with current high-precision methods. In addition to reference gases, calibration is achieved using air-equilibrated water standards of known temperature and salinity. Assessment of reference gas injections, air equilibrated standards, as well as samples collected in the field shows the accuracy...

  13. Evaluation strategies for isotope ratio measurements of single particles by LA-MC-ICPMS.

    Science.gov (United States)

    Kappel, S; Boulyga, S F; Dorta, L; Günther, D; Hattendorf, B; Koffler, D; Laaha, G; Leisch, F; Prohaska, T

    2013-03-01

    Data evaluation is a crucial step when it comes to the determination of accurate and precise isotope ratios computed from transient signals measured by multi-collector-inductively coupled plasma mass spectrometry (MC-ICPMS) coupled to, for example, laser ablation (LA). In the present study, the applicability of different data evaluation strategies (i.e. 'point-by-point', 'integration' and 'linear regression slope' method) for the computation of (235)U/(238)U isotope ratios measured in single particles by LA-MC-ICPMS was investigated. The analyzed uranium oxide particles (i.e. 9073-01-B, CRM U010 and NUSIMEP-7 test samples), having sizes down to the sub-micrometre range, are certified with respect to their (235)U/(238)U isotopic signature, which enabled evaluation of the applied strategies with respect to precision and accuracy. The different strategies were also compared with respect to their expanded uncertainties. Even though the 'point-by-point' method proved to be superior, the other methods are advantageous, as they take weighted signal intensities into account. For the first time, the use of a 'finite mixture model' is presented for the determination of an unknown number of different U isotopic compositions of single particles present on the same planchet. The model uses an algorithm that determines the number of isotopic signatures by attributing individual data points to computed clusters. The (235)U/(238)U isotope ratios are then determined by means of the slopes of linear regressions estimated for each cluster. The model was successfully applied for the accurate determination of different (235)U/(238)U isotope ratios of particles deposited on the NUSIMEP-7 test samples.

  14. On the cross-sensitivity between water vapor mixing ratio and stable isotope measurements of in-situ analyzers

    KAUST Repository

    Parkes, Stephen

    2015-04-01

    In recent years there has been an increasing amount of water vapor stable isotope data collected using in-situ instrumentation. A number of papers have characterized the performance of these in-situ analyzers and suggested methods for calibrating raw measurements. The cross-sensitivity of the isotopic measurements on the mixing ratio has been shown to be a major uncertainty and a variety of techniques have been suggested to characterize this inaccuracy. However, most of these are based on relating isotopic ratios to water vapor mixing ratios from in-situ analyzers when the mixing ratio is varied and the isotopic composition kept constant. An additional correction for the span of the isotopic ratio scale is then applied by measuring different isotopic standards. Here we argue that the water vapor cross-sensitivity arises from different instrument responses (span and offset) of the parent H2O isotope and the heavier isotopes, rather than spectral overlap that could cause a true variation in the isotopic ratio with mixing ratio. This is especially relevant for commercial laser optical instruments where absorption lines are well resolved. Thus, the cross-sensitivity determined using more conventional techniques is dependent on the isotopic ratio of the standard used for the characterization, although errors are expected to be small. Consequently, the cross-sensitivity should be determined by characterizing the span and zero offset of each isotope mixing ratio. In fact, this technique makes the span correction for the isotopic ratio redundant. In this work we model the impact of changes in the span and offset of the heavy and light isotopes and illustrate the impact on the cross-sensitivity of the isotopic ratios on water vapor. This clearly shows the importance of determining the zero offset for the two isotopes. The cross-sensitivity of the isotopic ratios on water vapor is then characterized by determining the instrument response for the individual isotopes for a

  15. On the cross-sensitivity between water vapor mixing ratio and stable isotope measurements of in-situ analyzers

    KAUST Repository

    Parkes, Stephen; Wang,  Lixin; McCabe, Matthew

    2015-01-01

    In recent years there has been an increasing amount of water vapor stable isotope data collected using in-situ instrumentation. A number of papers have characterized the performance of these in-situ analyzers and suggested methods for calibrating raw measurements. The cross-sensitivity of the isotopic measurements on the mixing ratio has been shown to be a major uncertainty and a variety of techniques have been suggested to characterize this inaccuracy. However, most of these are based on relating isotopic ratios to water vapor mixing ratios from in-situ analyzers when the mixing ratio is varied and the isotopic composition kept constant. An additional correction for the span of the isotopic ratio scale is then applied by measuring different isotopic standards. Here we argue that the water vapor cross-sensitivity arises from different instrument responses (span and offset) of the parent H2O isotope and the heavier isotopes, rather than spectral overlap that could cause a true variation in the isotopic ratio with mixing ratio. This is especially relevant for commercial laser optical instruments where absorption lines are well resolved. Thus, the cross-sensitivity determined using more conventional techniques is dependent on the isotopic ratio of the standard used for the characterization, although errors are expected to be small. Consequently, the cross-sensitivity should be determined by characterizing the span and zero offset of each isotope mixing ratio. In fact, this technique makes the span correction for the isotopic ratio redundant. In this work we model the impact of changes in the span and offset of the heavy and light isotopes and illustrate the impact on the cross-sensitivity of the isotopic ratios on water vapor. This clearly shows the importance of determining the zero offset for the two isotopes. The cross-sensitivity of the isotopic ratios on water vapor is then characterized by determining the instrument response for the individual isotopes for a

  16. Direct uranium isotope ratio analysis of single micrometer-sized glass particles

    OpenAIRE

    Kappel, Stefanie; Boulyga, Sergei F.; Prohaska, Thomas

    2012-01-01

    We present the application of nanosecond laser ablation (LA) coupled to a ‘Nu Plasma HR’ multi collector inductively coupled plasma mass spectrometer (MC-ICP-MS) for the direct analysis of U isotope ratios in single, 10–20 μm-sized, U-doped glass particles. Method development included studies with respect to (1) external correction of the measured U isotope ratios in glass particles, (2) the applied laser ablation carrier gas (i.e. Ar versus He) and (3) the accurate determination of lower abu...

  17. Carbon Isotopic Ratios of Amino Acids in Stardust-Returned Samples

    Science.gov (United States)

    Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

    2009-01-01

    NASA's Stardust spacecraft returned to Earth samples from comet 81P/Wild 2 in January 2006. Preliminary examinations revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds could not be identified. Here. we present the carbon isotopic ratios of glycine and E-aminocaproic acid (EACH), the two most abundant amino acids observed, in Stardust-returned foil samples measured by gas chromatography-combustion-isotope ratio crass spectrometry coupled with quadrupole mass spectrometry (GC-QMS/IRMS).

  18. On-line hydrogen-isotope measurements of organic samples using elemental chromium: An extension for high temperature elemental-analyzer techniques

    Science.gov (United States)

    Gehre, Matthias; Renpenning, Julian; Gilevska, Tetyana; Qi, Haiping; Coplen, Tyler B.; Meijer, Harro A.J.; Brand, Willi A.; Schimmelmann, Arndt

    2015-01-01

    The high temperature conversion (HTC) technique using an elemental analyzer with a glassy carbon tube and filling (temperature conversion/elemental analysis, TC/EA) is a widely used method for hydrogen isotopic analysis of water and many solid and liquid organic samples with analysis by isotope-ratio mass spectrometry (IRMS). However, the TC/EA IRMS method may produce inaccurate δ2H results, with values deviating by more than 20 mUr (milliurey = 0.001 = 1‰) from the true value for some materials. We show that a single-oven, chromium-filled elemental analyzer coupled to an IRMS substantially improves the measurement quality and reliability for hydrogen isotopic compositions of organic substances (Cr-EA method). Hot chromium maximizes the yield of molecular hydrogen in a helium carrier gas by irreversibly and quantitatively scavenging all reactive elements except hydrogen. In contrast, under TC/EA conditions, heteroelements like nitrogen or chlorine (and other halogens) can form hydrogen cyanide (HCN) or hydrogen chloride (HCl) and this can cause isotopic fractionation. The Cr-EA technique thus expands the analytical possibilities for on-line hydrogen-isotope measurements of organic samples significantly. This method yielded reproducibility values (1-sigma) for δ2H measurements on water and caffeine samples of better than 1.0 and 0.5 mUr, respectively. To overcome handling problems with water as the principal calibration anchor for hydrogen isotopic measurements, we have employed an effective and simple strategy using reference waters or other liquids sealed in silver-tube segments. These crimped silver tubes can be employed in both the Cr-EA and TC/EA techniques. They simplify considerably the normalization of hydrogen-isotope measurement data to the VSMOW-SLAP (Vienna Standard Mean Ocean Water-Standard Light Antarctic Precipitation) scale, and their use improves accuracy of the data by eliminating evaporative loss and associated isotopic fractionation while

  19. On-line hydrogen-isotope measurements of organic samples using elemental chromium: an extension for high temperature elemental-analyzer techniques.

    Science.gov (United States)

    Gehre, Matthias; Renpenning, Julian; Gilevska, Tetyana; Qi, Haiping; Coplen, Tyler B; Meijer, Harro A J; Brand, Willi A; Schimmelmann, Arndt

    2015-01-01

    The high temperature conversion (HTC) technique using an elemental analyzer with a glassy carbon tube and filling (temperature conversion/elemental analysis, TC/EA) is a widely used method for hydrogen isotopic analysis of water and many solid and liquid organic samples with analysis by isotope-ratio mass spectrometry (IRMS). However, the TC/EA IRMS method may produce inaccurate δ(2)H results, with values deviating by more than 20 mUr (milliurey = 0.001 = 1‰) from the true value for some materials. We show that a single-oven, chromium-filled elemental analyzer coupled to an IRMS substantially improves the measurement quality and reliability for hydrogen isotopic compositions of organic substances (Cr-EA method). Hot chromium maximizes the yield of molecular hydrogen in a helium carrier gas by irreversibly and quantitatively scavenging all reactive elements except hydrogen. In contrast, under TC/EA conditions, heteroelements like nitrogen or chlorine (and other halogens) can form hydrogen cyanide (HCN) or hydrogen chloride (HCl) and this can cause isotopic fractionation. The Cr-EA technique thus expands the analytical possibilities for on-line hydrogen-isotope measurements of organic samples significantly. This method yielded reproducibility values (1-sigma) for δ(2)H measurements on water and caffeine samples of better than 1.0 and 0.5 mUr, respectively. To overcome handling problems with water as the principal calibration anchor for hydrogen isotopic measurements, we have employed an effective and simple strategy using reference waters or other liquids sealed in silver-tube segments. These crimped silver tubes can be employed in both the Cr-EA and TC/EA techniques. They simplify considerably the normalization of hydrogen-isotope measurement data to the VSMOW-SLAP (Vienna Standard Mean Ocean Water-Standard Light Antarctic Precipitation) scale, and their use improves accuracy of the data by eliminating evaporative loss and associated isotopic fractionation while

  20. Fractionation of hydrogen isotopes by sulfate- and nitrate-reducing bacteria

    OpenAIRE

    Magdalena Rose Osburn; Katherine S Dawson; Marilyn L Fogel; Alex Sessions

    2016-01-01

    Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen –protium and deuterium –that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the magnitude of fractionation are observed for many heterotrophic microbes utilizing different central metabolic pathways. The correlation between metabolism and lipid δ2H provides a potential basis f...

  1. Experimental studies and modeling of processes of hydrogen isotopes interaction with beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Tazhibaeva, I.L.; Chikhray, Y.V.; Romanenko, O.G.; Klepikov, A.Kh.; Shestakov, V.P.; Kulsartov, T.V. [Science Research Inst. of Experimental and Theoretical Physics of Kazakh State Univ., Almaty (Kazakhstan); Kenzhin, E.A.

    1998-01-01

    The objective of this work was to clarify the surface beryllium oxide influence on hydrogen-beryllium interaction characteristics. Analysis of experimental data and modeling of processes of hydrogen isotopes accumulation, diffusion and release from neutron irradiated beryllium was used to achieve this purpose as well as the investigations of the changes of beryllium surface element composition being treated by H{sup +} and Ar{sup +} plasma glowing discharge. (author)

  2. Isotope analytics for the evaluation of the feeding influence on the isotope ratio in beef samples; Isotopenanalytik zur Bestimmung des Einflusses der Ernaehrung auf die Isotopenzusammensetzung in Rinderproben

    Energy Technology Data Exchange (ETDEWEB)

    Herwig, Nadine

    2010-11-17

    Information about the origin of food and associated production systems has a high significance for food control. An extremely promising approach to obtain such information is the determination of isotope ratios of different elements. In this study the correlation of the isotope ratios C-13/C-12, N-15/N-14, Mg-25/Mg-24, and Sr-87/Sr-86 in bovine samples (milk and urine) and the corresponding isotope ratios in feed was investigated. It was shown that in the bovine samples all four isotope ratios correlate with the isotope composition of the feed. The isotope ratios of strontium and magnesium have the advantage that they directly reflect the isotope ratios of the ingested feed since there is no isotope fractionation in the bovine organism which is in contrast to the case of carbon and nitrogen isotope ratios. From the present feeding study it is evident, that a feed change leads to a significant change in the delta C-13 values in milk and urine within 10 days already. For the deltaN-15 values the feed change was only visible in the bovine urine after 49 days. Investigations of cows from two different regions (Berlin/Germany and Goestling/Austria) kept at different feeding regimes revealed no differences in the N-15/N-14 and Mg-26/Mg-24 isotope ratios. The strongest correlation between the isotope ratio of the bovine samples and the kind of ingested feed was observed for the carbon isotope ratio. With this ratio even smallest differences in the feed composition were traceable in the bovine samples. Since different regions usually coincide with different feeding regimes, carbon isotope ratios can be used to distinguish bovine samples from different regions if the delta C-13 values of the ingested feed are different. Furthermore, the determination of strontium isotope ratios revealed significant differences between bovine and feed samples of Berlin and Goestling due to the different geologic realities. Hence the carbon and strontium isotope ratios allow the best

  3. Selected bibliography on heavy water, tritiated water and hydrogen isotopes (1981-1992)

    International Nuclear Information System (INIS)

    Gopalakrishnan, V.T.; Sutawane, U.B.; Rathi, B.N.

    1994-01-01

    A selected bibliography on heavy water, tritiated water and hydrogen isotopes is presented. This bibliography covers the period 1981-1992 and is in continuation to Division's earlier report BARC-1192 (1983). The sources of information for this compilation are Chemical Abstracts, INIS Atom Index and also some scattered search through journals and reports available in our library. No claim is made towards exhaustiveness of this bibliography even though sincere attempts have been made for a wide coverage. The bibliography is arranged under the headings: (1) production, purification, recovery, reprocessing and storage, (2) isotope exchange, 3) isotope analysis, (4) properties and (5) miscellaneous. Total number of references in the bibliography are 1762. (author)

  4. Spectral analysis software improves confidence in plant and soil water stable isotope analyses performed by isotope ratio infrared spectroscopy (IRIS).

    Science.gov (United States)

    West, A G; Goldsmith, G R; Matimati, I; Dawson, T E

    2011-08-30

    Previous studies have demonstrated the potential for large errors to occur when analyzing waters containing organic contaminants using isotope ratio infrared spectroscopy (IRIS). In an attempt to address this problem, IRIS manufacturers now provide post-processing spectral analysis software capable of identifying samples with the types of spectral interference that compromises their stable isotope analysis. Here we report two independent tests of this post-processing spectral analysis software on two IRIS systems, OA-ICOS (Los Gatos Research Inc.) and WS-CRDS (Picarro Inc.). Following a similar methodology to a previous study, we cryogenically extracted plant leaf water and soil water and measured the δ(2)H and δ(18)O values of identical samples by isotope ratio mass spectrometry (IRMS) and IRIS. As an additional test, we analyzed plant stem waters and tap waters by IRMS and IRIS in an independent laboratory. For all tests we assumed that the IRMS value represented the "true" value against which we could compare the stable isotope results from the IRIS methods. Samples showing significant deviations from the IRMS value (>2σ) were considered to be contaminated and representative of spectral interference in the IRIS measurement. Over the two studies, 83% of plant species were considered contaminated on OA-ICOS and 58% on WS-CRDS. Post-analysis, spectra were analyzed using the manufacturer's spectral analysis software, in order to see if the software correctly identified contaminated samples. In our tests the software performed well, identifying all the samples with major errors. However, some false negatives indicate that user evaluation and testing of the software are necessary. Repeat sampling of plants showed considerable variation in the discrepancies between IRIS and IRMS. As such, we recommend that spectral analysis of IRIS data must be incorporated into standard post-processing routines. Furthermore, we suggest that the results from spectral analysis be

  5. Novel Apparatus for the Real-Time Quantification of Dissolved Gas Concentrations and Isotope Ratios

    Science.gov (United States)

    Gupta, M.; Leen, J.; Baer, D. S.; Owano, T. G.; Liem, J.

    2013-12-01

    Measurements of dissolved gases and their isotopic composition are critical in studying a variety of phenomena, including underwater greenhouse gas generation, air-surface exchange, and pollution migration. These studies typically involve obtaining water samples from streams, lakes, or ocean water and transporting them to a laboratory, where they are degased. The gases obtained are then generally measured using gas chromatography and isotope ratio mass spectrometry for concentrations and isotope ratios, respectively. This conventional, off-line methodology is time consuming, significantly limits the number of the samples that can be measured and thus severely inhibits detailed spatial and temporal mapping of gas concentrations and isotope ratios. In this work, we describe the development of a new membrane-based degassing device that interfaces directly to Los Gatos Research (cavity enhanced laser absorption or Off-Axis ICOS) gas analyzers (cavity enhanced laser absorption or Off-Axis ICOS analyzers) to create an autonomous system that can continuously and quickly measure concentrations and isotope ratios of dissolved gases in real time in the field. By accurately controlling the water flow rate through the membrane degasser, gas pressure on the outside of the membrane, and water pressure on the inside of the membrane, the system is able to generate precise and highly reproducible results. Moreover, by accurately measuring the gas flow rates in and out of the degasser, the gas-phase concentrations (ppm) could be converted into dissolved gas concentrations (nM). We will present detailed laboratory test data that quantifies the linearity, precision, and dynamic range of the system for the concentrations and isotope ratios of dissolved methane, carbon dioxide, and nitrous oxide. By interfacing the degassing device to a novel cavity-enhanced spectrometer (developed by LGR), preliminary data will also be presented for dissolved volatile organics (VOC) and other

  6. The CN/C15N isotopic ratio towards dark clouds

    Science.gov (United States)

    Hily-Blant, P.; Pineau des Forêts, G.; Faure, A.; Le Gal, R.; Padovani, M.

    2013-09-01

    Understanding the origin of the composition of solar system cosmomaterials is a central question, not only in the cosmochemistry and astrochemistry fields, and requires various approaches to be combined. Measurements of isotopic ratios in cometary materials provide strong constraints on the content of the protosolar nebula. Their relation with the composition of the parental dark clouds is, however, still very elusive. In this paper, we bring new constraints based on the isotopic composition of nitrogen in dark clouds, with the aim of understanding the chemical processes that are responsible for the observed isotopic ratios. We have observed and detected the fundamental rotational transition of C15N towards two starless dark clouds, L1544 and L1498. We were able to derive the column density ratio of C15N over 13CN towards the same clouds and obtain the CN/C15N isotopic ratios, which were found to be 500 ± 75 for both L1544 and L1498. These values are therefore marginally consistent with the protosolar value of 441. Moreover, this ratio is larger than the isotopic ratio of nitrogen measured in HCN. In addition, we present model calculations of the chemical fractionation of nitrogen in dark clouds, which make it possible to understand how CN can be deprived of 15N and HCN can simultaneously be enriched in heavy nitrogen. The non-fractionation of N2H+, however, remains an open issue, and we propose some chemical way of alleviating the discrepancy between model predictions and the observed ratios. Appendices are available in electronic form at http://www.aanda.orgThe reduced spectra (in FITS format) are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A65

  7. Plutonium speciation and isotope ratios in Yenisey and Ob river and Yenisey estuary

    International Nuclear Information System (INIS)

    Skipperud, L.; Oughton, DH.; Fifield, K.; Lind, O.C.; Salbu, B.; Brown, J.

    2004-01-01

    Plutonium isotope ratios are known to vary with reactor type, nuclear fuel-burn up time, neutron flux, and energy, and for fallout from nuclear detonations, weapon type and yield. Weapons-grade plutonium is characterized by a low content of the 240 Pu isotope, with 240 Pu/ 239 Pu isotope ratio less than 0.05. In contrast, both global weapons fallout and spent nuclear fuel from civil reactors have higher 240 Pu/ 239 Pu isotope ratios (civil nuclear power reactors have 240 Pu/ 239 Pu atom ratios of between about 0.2-1). Thus, different sources often exhibit characteristic plutonium isotope ratios and these ratios can be used to identify the origin of contamination, calculate inventories, or follow the migration of contaminated sediments and waters. Together with activity measurements and isotope ratios, knowledge of plutonium speciation in the Ob and Yenisey rivers and processes controlling its behaviour in estuarine systems is a prerequisite for predicting the transfer and subsequent environmental impact to Arctic Seas. With this in mind, the study had two objectives: first to determine whether discharges from nuclear installations in the river catchment areas are having any influence on Pu levels in the estuaries; and, second, to investigate the transfer and mobility of plutonium in the Yenisey river and estuary. Plutonium 240/239 ratios were determined using accelerator mass spectrometry (AMS). The data indicated a clear influence from a low 240 Pu: 239 Pu source in surface sediments collected from the Yenisey Estuary, whereas plutonium in the Ob Estuary sediments are dominated by global fallout. The results also show an increase in plutonium concentration and a decrease in isotope ratio going upstream from the estuary. Sequential extractions of sediments indicate that up 70% of the Pu in the Yenisey river is easily mobilized with weak oxidizing agents, which indicates that the Pu is organically bound, while the Pu is more strongly irreversible bound further out

  8. Hydrogen isotope analysis of amino acids and whole cells reflects biosynthetic processing of nutrient- and water-derived hydrogen

    Science.gov (United States)

    Griffin, P.; Newsome, S.; Steele, A.; Fogel, M. L.

    2011-12-01

    Hydrogen (H) isotopes serve as sensitive tracers of biochemical processes that can be exploited to answer critical questions in biogeochemistry, ecology, and microbiology. Despite this apparent utility, relatively little is known about the specific mechanisms of H isotope fractionation involved in biosynthesis. In order to understand how organisms incorporate hydrogen from their chemical milieu into biomass, we have cultured the model bacterium E. coli MG1655 in a variety of media composed of deuterium-labeled nutrients and waters. Isotopic analysis of bulk cell mass reveals that the H fractionation between media water and cell material varies as a function of the nutrient source, with commonly used organic food sources (glucose and tryptone) leading to far smaller fractionation signals than non-standard ones (such as formamide, adenine, and urea). In addition, we have completed compound specific isotope analysis of amino acids using combined GC-IRMS. Amino acids harvested from E. coli cultured on glucose in water of varied D/H composition posses an extraordinary range of isotopic compositions (400-600 %). Furthermore, these amino acids follow a systematic distribution of D/H where proline is always heaviest and glycine is always lightest. However, when the short-chain peptide tryptone is used in place of glucose, only the non-essential amino acids reflect media water D/H values, suggesting the direct incorporation of some media-borne amino acids into cellular protein. These observations provide a foundation for understanding the cellular routing of hydrogen obtained from food and water sources and indicate that D/H analysis can serve as a powerful probe of biological function.

  9. Tracing contamination sources in soils with Cu and Zn isotopic ratios.

    Science.gov (United States)

    Fekiacova, Z; Cornu, S; Pichat, S

    2015-06-01

    Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ(65)Cu values vary from -0.15 to 0.44‰ and the δ(66)Zn from -0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from -0.95 to 0.44‰ for δ(65)Cu and from -0.53 to 0.64‰ for δ(66)Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. [Hydrogen production and enzyme activity of acidophilic strain X-29 at different C/N ratio].

    Science.gov (United States)

    Li, Qiu-bo; Xing, De-feng; Ren, Nan-qi; Zhao, Li-hua; Song, Ye-ying

    2006-04-01

    Some fermentative bacteria can produce hydrogen by utilizing carbohydrate and other kinds of organic compounds as substrates. Hydrogen production was also determined by both the limiting of growth and related enzyme activity in energy metabolism. Carbon and nitrogen are needed for the growth and metabolism of microorganisms. In addition, the carbon/nitrogen (C/N) ratio can influence the material metabolized and the energy produced. In order to improve the hydrogen production efficiency of the bacteria, we analyzed the effect of different C/N ratios on hydrogen production and the related enzyme activities in the acidophilic strain X-29 using batch test. The results indicate that the differences in the metabolism level and enzyme activity are obvious at different C/N ratios. Although the difference in liquid fermentative products produced per unit of biomass is not obvious, hydrogen production is enhanced at a specifically determined ratio. At a C/N ratio of 14 the accumulative hydrogen yield of strain X-29 reaches the maximum, 2210.9 mL/g. At different C/N ratios, the expression of hydrogenase activity vary; the activity of hydrogenase decrease quickly after reaching a maximum along with the fermentation process, but the time of expression is short. The activity of alcohol dehydrogenase (ADH) tend to stabilize after reaching a peak along with the fermentation process, the difference in expression activity is little, and the expression period is long at different C/N ratios. At a C/N ratio of 14 hydrogenase and ADH reach the maximum 2.88 micromol x (min x mg)(-1) and 33.2 micromol x (min x mg)(-1), respectively. It is shown that the C/N ratio has an important effect on enhancing hydrogen production and enzyme activity.

  11. Assessing connectivity of estuarine fishes based on stable isotope ratio analysis

    Science.gov (United States)

    Herzka, Sharon Z.

    2005-07-01

    Assessing connectivity is fundamental to understanding the population dynamics of fishes. I propose that isotopic analyses can greatly contribute to studies of connectivity in estuarine fishes due to the high diversity of isotopic signatures found among estuarine habitats and the fact that variations in isotopic composition at the base of a food web are reflected in the tissues of consumers. Isotopic analysis can be used for identifying nursery habitats and estimating their contribution to adult populations. If movement to a new habitat is accompanied by a shift to foods of distinct isotopic composition, recent immigrants and residents can be distinguished based on their isotopic ratios. Movement patterns thus can be reconstructed based on information obtained from individuals. A key consideration is the rate of isotopic turnover, which determines the length of time that an immigrant to a given habitat will be distinguishable from a longtime resident. A literature survey indicated that few studies have measured turnover rates in fishes and that these have focused on larvae and juveniles. These studies reveal that biomass gain is the primary process driving turnover rates, while metabolic turnover is either minimal or undetectable. Using a simple dilution model and biomass-specific growth rates, I estimated that young fishes with fast growth rates will reflect the isotopic composition of a new diet within days or weeks. Older or slower-growing individuals may take years or never fully equilibrate. Future studies should evaluate the factors that influence turnover rates in fishes during various stages of the life cycle and in different tissues, as well as explore the potential for combining stable isotope and otolith microstructure analyses to examine the relationship between demographic parameters, movement and connectivity.

  12. Determination of Light Water Reactor Fuel Burnup with the Isotope Ratio Method

    International Nuclear Information System (INIS)

    Gerlach, David C.; Mitchell, Mark R.; Reid, Bruce D.; Gesh, Christopher J.; Hurley, David E.

    2007-01-01

    For the current project to demonstrate that isotope ratio measurements can be extended to zirconium alloys used in LWR fuel assemblies we report new analyses on irradiated samples obtained from a reactor. Zirconium alloys are used for structural elements of fuel assemblies and for the fuel element cladding. This report covers new measurements done on irradiated and unirradiated zirconium alloys, Unirradiated zircaloy samples serve as reference samples and indicate starting values or natural values for the Ti isotope ratio measured. New measurements of irradiated samples include results for 3 samples provided by AREVA. New results indicate: 1. Titanium isotope ratios were measured again in unirradiated samples to obtain reference or starting values at the same time irradiated samples were analyzed. In particular, 49Ti/48Ti ratios were indistinguishably close to values determined several months earlier and to expected natural values. 2. 49Ti/48Ti ratios were measured in 3 irradiated samples thus far, and demonstrate marked departures from natural or initial ratios, well beyond analytical uncertainty, and the ratios vary with reported fluence values. The irradiated samples appear to have significant surface contamination or radiation damage which required more time for SIMS analyses. 3. Other activated impurity elements still limit the sample size for SIMS analysis of irradiated samples. The sub-samples chosen for SIMS analysis, although smaller than optimal, were still analyzed successfully without violating the conditions of the applicable Radiological Work Permit

  13. A Three End-Member Mixing Model Based on Isotopic Composition and Elemental Ratio

    Directory of Open Access Journals (Sweden)

    Kon-Kee Liu Shuh-Ji Kao

    2007-01-01

    Full Text Available A three end-member mixing model based on nitrogen isotopic composition and organic carbon to nitrogen ratio of suspended particulate matter in an aquatic environment has been developed. Mathematical expressions have been derived for the calculation of the fractions of nitrogen or organic carbon originating from three different sources of distinct isotopic and elemental compositions. The model was successfully applied to determine the contributions from anthropogenic wastes, soils and bedrock-derived sediments to particulate nitrogen and particulate organic carbon in the Danshuei River during the flood caused by Typhoon Bilis in August 2000. The model solutions have been expressed in a general form that allows applications to mixtures with other types of isotopic compositions and elemental ratios or in forms other than suspended particulate matter.

  14. Locally Grown, Natural Ingredients? The Isotope Ratio Can Reveal a Lot!

    Science.gov (United States)

    Rossier, Joël S; Maury, Valérie; Pfammatter, Elmar

    2016-01-01

    This communication gives an overview of selected isotope analyses applied to food authenticity assessment. Different isotope ratio detection technologies such as isotope ratio mass spectrometry (IRMS) and cavity ring down spectroscopy (CRDS) are briefly described. It will be explained how δ(18)O of water contained in fruits and vegetables can be used to assess their country of production. It will be explained why asparagus grown in Valais, in the centre of the Alps carries much less heavy water than asparagus grown closer to the sea coast. On the other hand, the use of δ(13)C can reveal whether a product is natural or adulterated. Applications including honey or sparkling wine adulteration detection will be briefly presented.

  15. A versatile method for simultaneous stable carbon isotope analysis of DNA and RNA nucleotides by liquid chromatography/isotope ratio mass spectrometry

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Brasser, J.; de Ruiter, G.; Houtekamer, M.; Bolhuis, H.; Stal, L.J.; Boschker, H.T.S.

    2014-01-01

    RATIONALELiquid chromatography/isotope ratio mass spectrometry (LC/IRMS) is currently the most accurate and precise technique for the measurement of compound-specific stable carbon isotope ratios (C-13/C-12) in biological metabolites, at their natural abundance. However, until now this technique

  16. Solubility of hydrogen isotopes in stressed hydride-forming metals

    International Nuclear Information System (INIS)

    Coleman, C.E.; Ambler, J.F.R.

    1983-01-01

    Components made from hydride-forming metals can be brittle when particles of hydride are present. The solid solubility limit of hydrogen in these metals needs to be known so that fracture resistance can be properly assessed. Stress affects the solubility of hydrogen in metals. As hydrogen dissolves the metal volume increases, an applied hydrostatic tensile stress supplies work to increase the solubility. Precipitation of hydrides increases the volume further. A hydrostatic tensile stress promotes the formation of hydrides and tends to reduce the terminal solubility. For materials containing hydrogen in solution in equilibrium with hydrides, the effect of stress on the terminal solubility is given. Hydrogen migrates up tensile stress gradients because of the effect of stress on the solubility and solubility limit. Consequently, hydrogen concentrates at flaws. When hydrides are present in the metal matrix, those remote from the flaw tip will preferentially dissolve in favor of those precipitated at the flaw. If the stress is large enough, at some critical condition the hydrides at the flaw will crack. This is delayed hydrogen cracking. Notched and fatigue-cracked cantilever beam specimens (6) (38 x 4 x 3 mm) were machined from the circumferential direction of several cold-worked Zr-2.5 at. % Nb pressure tubes. The chemical compositions had the ranges (in atomic %) Nb - 2.5 to 2.7; O - 0.58 to 0.71; H - 0.018 to 0.18. The effect of test temperature is for a specimen containing 0.13 at. % protium and 0.29 at .% deuterium. Between 505 K and 530 K was less than 1 hr, between 530 K and 537 K it increased to 25.8 h, while at 538 K no cracking was observed up to the 54 h

  17. Numerical analysis on the ion species ratios in a steady state hydrogen plasma

    International Nuclear Information System (INIS)

    Fukumasa, Osamu; Saeki, Setsuo; Osaki, Katashi; Sakiyama, Satoshi; Itatani, Ryohei.

    1984-07-01

    Ion species ratios in a hydrogen plasma are calculated systematically as a function of plasma parameters, i.e. the electron density, the electron temperature, the pressure of hydrogen gas and the plasma volume. Furthermore, in the present analysis, the recombination factor for hydrogen atoms at the wall surface of a vacuum vessel is treated as another plasma parameter. The most significant point is that ion species ratios depend strongly not only on plasma parameters, but also on the recombination factor. The proton ratio increases with decreasing value of the recombination factor. Primary electrons also play an important role for ion species ratios, and the presence of primary electrons causes the proton ratio to decrease. (author)

  18. A calculation of the surface recombination rate constant for hydrogen isotopes on metals

    International Nuclear Information System (INIS)

    Baskes, M.J.

    1980-01-01

    The surface recombination rate constant for hydrogen isotopes on a metal has been calculated using a simple model whose parameters may be determined by direct experimental measurements. Using the experimental values for hydrogen diffusivity, solubility, and sticking coefficient at zero surface coverage a reasonable prediction of the surface recombination constant may be made. The calculated recombination constant is in excellent agreement with experiment for bcc iron. A heuristic argument is developed which, along with the rate constant calculation, shows that surface recombination is important in those metals in which hydrogen has an exothermic heat of solution. (orig.)

  19. Computer-controlled detection system for high-precision isotope ratio measurements

    International Nuclear Information System (INIS)

    McCord, B.R.; Taylor, J.W.

    1986-01-01

    In this paper the authors describe a detection system for high-precision isotope ratio measurements. In this new system, the requirement for a ratioing digital voltmeter has been eliminated, and a standard digital voltmeter interfaced to a computer is employed. Instead of measuring the ratio of the two steadily increasing output voltages simultaneously, the digital voltmeter alternately samples the outputs at a precise rate over a certain period of time. The data are sent to the computer which calculates the rate of charge of each amplifier and divides the two rates to obtain the isotopic ratio. These results simulate a coincident measurement of the output of both integrators. The charge rate is calculated by using a linear regression method, and the standard error of the slope gives a measure of the stability of the system at the time the measurement was taken

  20. Dating of oilfield contamination by Natural Occurring Radioactive Materials (NORM) using isotopic ratios

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Othman, I.; Aba, A.

    2008-05-01

    In the present work, the possibility of using radium isotope ratios (226, 224, 228) for dating of NORM contaminated sites in the oilfields due to uncontrolled disposal of produced water into the environmental NORM contaminated soil sample were collected from different locations in Syrian Oilfields and radioactivity analysed. In addition, production water samples were collected and analysed to determine the isotopes ratios of the naturally occurring radioactive materials. The results have shown that the 228 Ra/ 226 Ra can be successfully used to date contaminated soil provided that this ratio is determined in production water. Moreover, the 210 Pb/ 226 Ra activity ratios was used for the first time for dating of contaminated soil where all factors affecting the method application have been evaluated. Furthermore, the obtained results for dating using the three methods were compared with the actual contamination dates provided by the oil companies. (Authors)

  1. Tracing contamination sources in soils with Cu and Zn isotopic ratios

    Energy Technology Data Exchange (ETDEWEB)

    Fekiacova, Z.; Cornu, S. [INRA, UR 1119 Géochimie des Sols et des Eaux, F-13100 Aix en Provence (France); Pichat, S. [Laboratoire de Géologie de Lyon (LGL-TPE), Ecole Normale Supérieure de Lyon, CNRS, UMR 5276, 69007 Lyon (France)

    2015-06-01

    Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ{sup 65}Cu values vary from − 0.15 to 0.44‰ and the δ{sup 66}Zn from − 0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from − 0.95 to 0.44‰ for δ{sup 65}Cu and from − 0.53 to 0.64‰ for δ{sup 66}Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case. - Highlights: • Pedogenetic processes produce some Cu and Zn isotope fractionation. • Pollution with distinct isotopic signatures can be traced using Cu and Zn isotopes. • Tracing

  2. Tracing contamination sources in soils with Cu and Zn isotopic ratios

    International Nuclear Information System (INIS)

    Fekiacova, Z.; Cornu, S.; Pichat, S.

    2015-01-01

    Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ 65 Cu values vary from − 0.15 to 0.44‰ and the δ 66 Zn from − 0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from − 0.95 to 0.44‰ for δ 65 Cu and from − 0.53 to 0.64‰ for δ 66 Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case. - Highlights: • Pedogenetic processes produce some Cu and Zn isotope fractionation. • Pollution with distinct isotopic signatures can be traced using Cu and Zn isotopes. • Tracing of the metal

  3. Salinity dependent hydrogen isotope fractionation in alkenones produced by coastal and open ocean haptophyte algae

    NARCIS (Netherlands)

    M'boule, D.; Chivall, D.; Sinke-Schoen, D.; Sinninghe Damsté, J.S.; Schouten, S.; van der Meer, M.T.J.

    2014-01-01

    The hydrogen isotope fractionation in alkenones produced by haptophyte algae is a promising new proxy for paleosalinity reconstructions. To constrain and further develop this proxy the coastal haptophyte Isochrysis galbana and the open ocean haptophyte alga Emiliania huxleyi were cultured at

  4. Studies on the magnetic after-effect of hydrogen isotopes in hexagonal crystals

    International Nuclear Information System (INIS)

    Herbst, G.

    1979-01-01

    The behaviour of hydrogen isotopes in hexagonal gadolinium, in intermetallic compounds of the RECo 5 type (RE = rare earth metal), and in cobalt alloys with small concentrations of alloyed impurity atoms was studied using the magnetic after-effect method in the temperature range between 4.2 K and 300 K. (orig./WBU) [de

  5. Isotopic and spin-nuclear effects in solid hydrogens (Review Article)

    Science.gov (United States)

    Freiman, Yuri A.; Crespo, Yanier

    2017-12-01

    The multiple isotopic family of hydrogens (H2, HD, D2, HT, DT, T2) due to large differences in the de Boer quantum parameter and inertia moments displays a diversity of pronounced quantum isotopic solid-state effects. The homonuclear members of this family (H2, D2, T2) due to the permutation symmetry are subjects of the constraints of quantum mechanics which link the possible rotational states of these molecules to their total nuclear spin giving rise to the existence of two spin-nuclear modifications, ortho- and parahydrogens, possessing substantially different properties. Consequently, hydrogen solids present an unique opportunity for studying both isotope and spin-nuclear effects. The rotational spectra of heteronuclear hydrogens (HD, HT, DT) are free from limitations imposed by the permutation symmetry. As a result, the ground state of these species in solid state is virtually degenerate. The most dramatic consequence of this fact is an effect similar to the Pomeranchuk effect in 3He which in the case of the solid heteronuclear hydrogens manifests itself as the reentrant broken symmetry phase transitions. In this review article we discuss thermodynamic and kinetic effects pertaining to different isotopic and spin-nuclear species, as well as problems that still remain to be solved.

  6. ANALYTICAL EMPLOYMENT OF STABLE ISOTOPES OF CARBON, NITROGEN, OXYGEN AND HYDROGEN FOR FOOD AUTHENTICATION

    Directory of Open Access Journals (Sweden)

    E. Novelli

    2011-04-01

    Full Text Available Stable isotopes of carbon, nitrogen, oxygen and hydrogen were used for analytical purposes for the discrimination of the type of production (farming vs. fishing in the case of sea bass and for geographical origin in the case of milk. These results corroborate similar experimental evidences and confirm the potential of this analytical tool to support of food traceability.

  7. Determination of 239Pu/240Pu isotopic ratio by high resolution alpha-particle spectrometry

    International Nuclear Information System (INIS)

    Amoudry, F.; Burger, P.

    1983-05-01

    The development of passivated ion-implanted silicon detectors and of very thin alpha-particle sources improves the resolution of alpha-particle spectra and allows to separate energy pics up to now unseparate. The 239 Pu/ 240 Pu isotopic ratio of a mixture has been measured using the alpha spectrometry deconvolution code DEMO [fr

  8. High dynamic range isotope ratio measurements using an analog electron multiplier

    Czech Academy of Sciences Publication Activity Database

    Williams, P.; Lorinčík, Jan; Franzreb, K.; Herwig, R.

    2013-01-01

    Roč. 45, č. 1 (2013), s. 549-552 ISSN 0142-2421 R&D Projects: GA MŠk ME 894 Institutional support: RVO:67985882 Keywords : Isotope ratios * electron multiplier * dynamic range Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.393, year: 2013

  9. Carbon and oxygen isotopic ratio bi-variate distribution for marble artifacts quarry assignment

    International Nuclear Information System (INIS)

    Pentia, M.

    1995-01-01

    Statistical description, by a Gaussian bi-variate probability distribution of 13 C/ 12 C and 18 O/ 16 O isotopic ratios in the ancient marble quarries has been done and the new method for obtaining the confidence level quarry assignment for marble artifacts has been presented. (author) 8 figs., 3 tabs., 4 refs

  10. Influence of forest disturbance on stable nitrogen isotope ratios in soil and vegetation profiles

    Science.gov (United States)

    Jennifer D. Knoepp; Scott R. Taylor; Lindsay R. Boring; Chelcy F. Miniat

    2015-01-01

    Soil and plant stable nitrogen isotope ratios (15 N) are influenced by atmospheric nitrogen (N) inputs and processes that regulate organic matter (OM) transformation and N cycling. The resulting 15N patterns may be useful for discerning ecosystem differences in N cycling. We studied two ecosystems; longleaf pine wiregrass (...

  11. Lithologically inherited variation in Pb isotope ratios in sedimentary soils in The Netherlands

    NARCIS (Netherlands)

    Walraven, N.; Gaans, P.F.M. van; Veer, G. van der; Os, B.J.H. van; Klaver, G.T.; Vriend, S.P.; Middelburg, J.J.; Davies, G.R.

    2013-01-01

    Knowledge on the lithologically inherited variation in present day Pb isotope ratios in soils is remarkably limited. Such information is essential to determine the anthropogenic Pb fraction and anthropogenic Pb sources in Pb-polluted soils. This study presents results of a survey of subsoil samples

  12. Measurement of stable isotope ratio of organic carbon in water samples

    International Nuclear Information System (INIS)

    Fujii, Toshihiro; Otsuki, Akira

    1977-01-01

    A new method for the measurement of stable isotope ratios was investigated and applied to organic carbon's isotope ratio measurements in water samples. A few river water samples from Tsuchiura city were tested. After the wet oxidation of organic carbons to carbon dioxide in a sealed ampoule, the isotope ratios were determined with the gas chromatograph-quadrupole mass spectrometer combined with a total organic carbon analyser, under the dynamic conditions. The GC-MS had been equipped with the multiple ion detector-digital integrator system. The ion intensities at m/e 44 and 45 were simultaneously measured at a switching rate of 1 ms. The measurements with carbon dioxide acquired from sodium carbonate (53 μg) gave the isotope ratios with the variation coefficient of 0.62%. However, the variation coefficients obtained from organic carbons in natural water samples were 2 to 3 times as high as that from sodium carbonate. This method is simple and rapid and may be applied to various fields especially in biology and medicine. (auth.)

  13. Evaluation of precision in measurements of uranium isotope ratio by thermionic mass spectrometry

    International Nuclear Information System (INIS)

    Moraes, N.M.P. de; Rodrigues, C.

    1977-01-01

    The parameters which affect the precision and accuracy of uranium isotopic ratios measurements by thermionic mass spectrometry are discussed. A statistical designed program for the analysis of the internal and external variances are presented. It was done an application of this statistical methods, in order to get mass discrimination factor, and its standard mean deviation, by using some results already published for 235 U/ 238 U ratio in NBS uranium samples, and natural uranium [pt

  14. Water containing deuterium electrolysis to obtain gaseous hydrogen isotope in a high state of purity

    International Nuclear Information System (INIS)

    Bellanger, Gilbert

    1992-01-01

    In this paper, the basic concept is to prepare hydrogen in a high state of purity by electrolysing water using a palladium cathode. During electrolysis, hydrogen is at first adsorbed at the palladium surface, and next it diffuses through it till opposite face of its entry where it is desorbed; thus permitting to regain it in a very pure state for storage. The method can be used from water containing deuterium. To improve hydrogen adsorption, surface effect of palladium must be studied. It was found that heat treatment of palladium improved the hydrogen permeation flux. The diffusivity of hydrogen is controlled by Fick and Sieverts equations in which temperature has a significant influence on permeation rates. Anyway, hydrogen desorption does not cause any difficulty. In a second part, we have studied the isotopic separation factor using water containing deuterium. We remarked in fact that it depends on current density, overpotential, diffusivity of hydrogen and deuterium and isotopic composition of electrolyte as expected. In the last part, we realized an original electrolysis model in a glove-box in which are taken into account the results given before and also the technology components employed in processes involving the use of tritium. (author) [fr

  15. The high pressure equation of state of the isotopes of solid hydrogen and helium

    International Nuclear Information System (INIS)

    Driessen, A.

    1982-01-01

    The initial aim of this thesis was to provide the high pressure equipment and the knowledge about the equation of state (EOS) necessary for a research program in a laboratory dealing with spectroscopy of solid hydrogen under high pressure. Once this first goal was reached, a logical step was to extend the work on the EOS to all three hydrogen isotopes and later also to the helium isotpes. During the experiments on the EOS of hydrogen, the effects of the concentration C 1 of the rotationally excited molecules provoked interest, resulting in an extensive experimental and theoretical study. Chapter I describes the results and experience with high pressure equipment for hydrogen up to 7 kbar and chapter II gives a short general introduction to the calculation of the EOS by introducing the Mie-Grueneisen picture and the Silvera-Goldman (SG) potential for hydrogen. Chapter III gives the results of the first EOS of H 2 and D 2 and chapter IV gives a prediction of the EOS of solid T 2 with aid of the SG potential and the experimental results of H 2 and D 2 . Chapter V presents calculations on the thermal expansion of the hydrogen isotopes, which are compared with direct experiments and chapter VI deals in detail with the influence of C 1 on the EOS of H 2 . Ortho-para conversion in hydrogen is considered in chapter VII, and chapter VIII describes experiments on 4 He. (Auth.)

  16. Chromatographic measurement of hydrogen isotopic and permanent gas impurities in tritium

    International Nuclear Information System (INIS)

    Warner, D.K.; Kinard, C.; Bohl, D.C.

    1976-01-01

    This paper describes a gas chromatograph that was designed for dedicated analysis of hydrogen isotopic and permanent gas impurities in tritium and tritium-deuterium mixtures. The instrument that was developed substantially improved the accuracy and precision of hydrogen isotopic analysis in the 20 ppM to one mole percent range as compared with other analytical methods. Several unique design features of the instrument were required due to the radiation and isotopic exchange properties of the tritium in the samples; descriptions of these features are presented along with details of the complete chromatographic system. The experimental procedures used to calibrate the detector and statistically evaluate its performance are given, and the sources of analytical error are cited. The limitations of the present system are also discussed

  17. Traceability of different apple varieties by multivariate analysis of isotope ratio mass spectrometry data.

    Science.gov (United States)

    Mimmo, Tanja; Camin, Federica; Bontempo, Luana; Capici, Calogero; Tagliavini, Massimo; Cesco, Stefano; Scampicchio, Matteo

    2015-11-15

    The awareness of customers of the origin of foods has become an important issue. The growing demand for foods that are healthy, safe and of high quality has increased the need for traceability and clear labelling. Thus, this study investigates the capability of C and N stable isotope ratios to determine the geographical origin of several apple varieties grown in northern Italy. Four apple varieties (Cripps Pink, Gala, Golden Delicious, Granny Smith) have been sampled in orchards located in the Districts of Bolzano, Ferrara, Verona and Udine (northern Italy). Carbon (δ(13) C) and nitrogen (δ(15) N) isotope values of the whole apple fruits and three sub-fractions (peel, pulp and seed) have been determined simultaneously by isotope ratio mass spectrometry. The δ(13) C and δ(15) N values of apples and apple sub-fractions, such as peel, seed and pulp, were significantly affected by the geographical origin and the fruit variety. The four varieties could be distinguished to a certain extent only within each district. A 99% correct identification of the samples according to their origin was, however, achieved by cross validation with the 'leave-one-out' method. This study proves the potential of stable isotopes to discriminate the geographical origin of apples grown in orchards located only a few hundreds of kilometres apart. Stable isotopes were also able to discriminate different apple varieties, although only within small geographical areas. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Yields and isomeric ratio of xenon and krypton isotopes from thermal neutron fission of 235U

    International Nuclear Information System (INIS)

    Hsu, S.S.; Lin, J.T.; Yang, C.M.; Yu, Y.W.

    1981-01-01

    The experimental cumulative yields of 85 Kr/sup m/, 87 Kr, 88 Kr, 133 Xe/sup g/, 135 Xe/sup m/, and 135 Xe/sup g/ and the independent isomeric yield of 133 Xe/sup m/ in the thermal neutron fission of 235 U have been measured by the gas chromatographic method. The independent yields of 133 Xe/sup g/, 135 Xe/sup m/, and 135 Xe/sup g/ were deduced with the aid of 133 I and 135 I data. The isomeric yield ratios of 133 Xe and 135 Xe have been computed and compared with theoretical values since they have the same high spin state J = 11/2 - and low spin ground state J = 3/2 + . The influence of the shell effect on the fission isomeric yield ratio is discussed. From the measured independent yield of Xe isotopes plus the reported data, the Xe-isotopic distribution curve has been constructed. The curve is compared with the isotopic distribution curves of Xe isotopes formed in 11.5 GeV proton interactions with 238 U and Cs isotopes formed in 24 GeV proton interactions with 238 U. Upon fitting the yield curves we find that only those products with N/Z> or =1.48 fit a curve typical of a binary fission process

  19. Forensic utility of the carbon isotope ratio of PVC tape backings

    Science.gov (United States)

    Stern, L. A.; Thompson, A. H.; Mehltretter, A. H.; McLaskey, V.; Parish, A.; Aranda, R.

    2008-12-01

    Forensic interest in adhesive tapes with PVC-backings (polyvinyl chloride, electrical tapes) derives from their use in construction of improvised explosive devices, drug packaging and in a variety of other illicit activities. Due to the range of physical characteristics and chemical compositions of such tapes, traditional microscopic and chemical analysis of the tape backings and adhesives offer a high degree of discrimination between tapes from different manufacturers and products. To evaluate whether carbon isotope ratios may be able to increase discrimination of electrical tapes, particularly with regards to different tapes of the same product, we assessed the PVC-backings of 87 rolls of black electrical tape for their δ13C values. The adhesive on these tapes was physically removed with hexane, and plasticizers within the PVC tape backings were removed by three-20 minute extractions with chloroform. The δ13C values of the PVC tape backings ranged between -23.8 and -41.5 (‰ V-PDB). The carbon isotopic variation within a product (identical brand and product identification) is significant, based on five products with at least 3 rolls (ranges of 7.4‰ (n=3), 10.0‰ (n=6), 4.2‰ (n=16), 3.8‰ (n=6), and 11.5‰ (n=8), respectively). There was no measurable carbon isotope variation in regards to the following: a) along the length of a roll (4 samples from 1 roll); b) between the center and edge of a strip of tape (1 pair); c) between rolls assumed to be from the same lot of tape (2 pairs); d) between different rolls from the same batch of tape (same product purchased at the same time and place; 5 pairs); and e) between samples of a tape at room temperature, heated to 50° C and 80° C for 1 week. For each sample within the population of 87 tapes, carbon isotopes alone exclude 80 to 100% of the tapes as a potential match, with an average exclusion power of 92.5%, using a window of ± 0.4‰. Carbon isotope variations originate from variations in starting

  20. Large effect of irradiance on hydrogen isotope fractionation of alkenones in Emiliania huxleyi

    Science.gov (United States)

    van der Meer, Marcel T. J.; Benthien, Albert; French, Katherine L.; Epping, Eric; Zondervan, Ingrid; Reichart, Gert-Jan; Bijma, Jelle; Sinninghe Damsté, Jaap S.; Schouten, Stefan

    2015-07-01

    The hydrogen isotopic (δD) composition of long-chain alkenones produced by certain haptophyte algae has been suggested as a potential proxy for reconstructing paleo sea surface salinity. However, environmental parameters other than salinity may also affect the δD of alkenones. We investigated the impact of the level of irradiance on hydrogen isotopic fractionation of alkenones versus growth water by cultivating two strains of the cosmopolitan haptophyte Emiliania huxleyi at different light intensities. The hydrogen isotope fractionation decreased by approximately 40‰ when irradiance was increased from 15 to 200 μmol photons m-2 s-1 above which it was relatively constant. The response is likely a direct effect of photosystem I and II activity as the relationship of the fractionation factor α versus light intensity can be described by an Eilers-Peeters photosynthesis model. This irradiance effect is in agreement with published δD data of alkenones derived from suspended particulate matter collected from different depths in the photic zone of the Gulf of California and the eastern tropical North Pacific. However, haptophyte algae tend to bloom at relatively high light intensities (>500 μmol photons m-2 s-1) occurring at the sea surface, at which hydrogen isotope fractionation is relatively constant and not affected by changes in light intensity. Alkenones accumulating in the sediment are likely mostly derived from these surface water haptophyte blooms, when the largest amount of biomass is produced. Therefore, the observed irradiance effect is unlikely to affect the applicability of the hydrogen isotopic composition of sedimentary long chain alkenones as a proxy for paleosalinity.

  1. Chemically modified glasses for analysis of hydrogen isotopes by gas-chromatography

    International Nuclear Information System (INIS)

    Stanciu, Vasile; Stefanescu, Doina

    1999-01-01

    Hydrogen isotope separation process by such methods as cryogenic distillation or thermal diffusion method is one of the key technologies of the tritium separation from heavy water of CANDU reactors and in the tritium fuel cycle for a thermonuclear fusion reactor. In each process, the analytical techniques for measuring contents of hydrogen isotope mixture are necessary. An extensive experimental research has been carried out in order to produce the most suitable absorbent and define the best operating conditions for selective separation and analysis of hydrogen isotope by gas-chromatography. This paper describes the preparation of adsorbent materials utilised as stationary phase in the gas-chromatographic column for hydrogen isotope separation and treatment (activation) of stationary phase. Modified thermo-resisting glass with Fe(NH 4 ) 2 (SO 4 ) 2 6H 2 O and Cr 2 O 3 , respectively, have been experimentally investigated at 77 K for H 2 , HD and D 2 separation and the results of chromatographic runs are also reported and discussed. The gas-chromatographic apparatus used is composed of a Hewlett-Packard 7620A gas-chromatograph equipped with a gas carrier flow rate controller and a thermal conductivity detector (TCD). The apparatus comprises also a Dewar vessel containing the separation column. The hydrogen isotopes H 2 , HD, D 2 and their mixture have been obtained in our laboratories. The best operating conditions of the adsorbent column Fe (III)/glass and Cr 2 O 3 /glass, i.e. granulometry, column length, pressure-drop along the column, carrier gas flow rate, sample volume have been studied by means of the analysis of the retention times, separation factors and HETP. (authors)

  2. Metal/glass composites for analysis of hydrogen isotopes by gas-chromatography

    International Nuclear Information System (INIS)

    Nicolae, Constantin Adrian; Sisu, Claudia; Stefanescu, Doina; Stanciu, Vasile

    1999-01-01

    The separation process of hydrogen isotopes by cryogenic distillation or thermal diffusion is a key technology for tritium separation from heavy water in CANDU reactor and for tritium fuel cycle in thermonuclear fusion reactor. In each process, analytical techniques for analyzing the hydrogen isotope mixture are required. An extensive experimental research has been carried out in order to produce the most suitable adsorbents and to establish the best operating conditions for selective separation and analysis of hydrogen isotopes by gas-chromatography. This paper describes the preparation of adsorbent materials used as stationary phases in the gas-chromatographic column for hydrogen isotope separation and the treatment (activation) of stationary phases. Modified thermoresisting glass with Fe(NH 4 ) 2 (SO 4 ) 2 ·6H 2 O and Cr 2 O 3 respectively have been experimentally investigated at 77 K for H 2 , HD and D 2 separation and the results of chromatographic runs are reported and discussed. The gas-chromatographic apparatus used in this study is composed of a Hewlett-Packard 7620A gas-chromatograph equipped with a gas carrier flow rate controller and a thermal conductivity detector. The apparatus comprises also a Dewar vessel containing the separation column. The hydrogen isotopes, H 2 , HD, D 2 , and their mixture have been obtained in our laboratories. The best operating conditions and parameters of the Fe 3+ /glass adsorbent column , i.e. granulometry, column length, pressure-drop along the column, carrier gas flow rate and sample volume have been studied by means of the analysis of the retention times, separation factors and HETP. (authors)

  3. Emerging techniques in vegetable oil analysis using stable isotope ratio mass spectrometry

    Directory of Open Access Journals (Sweden)

    Rhodes, Christopher

    2002-03-01

    Full Text Available As the practice of vegetable oil adulteration becomes more sophisticated, the possibility to subvert detection using established techniques such as capillary gas chromatography is increasing. One of the most powerful techniques to be used in food authenticity studies is stable isotope ratio mass spectrometry (SIRMS which utilises differences in the natural abundance of the stable isotopes of the ‘light’ bio-elements hydrogen, nitrogen, carbon, oxygen and sulfur to detect food fraud. SIRMS has found application in the authentication of a wide range of foodstuffs, including fruit juices, wines, spirits, honey and to detect the adulteration of flavour compounds with synthetic analogues. This papers reviews the current state-of-the-art for the authentication of vegetable oils using SIRMS and highlights emergent techniques such as compound- and position specific-isotope mass spectrometry. These latter developments offer the potential to provide more rapid and improved detection of the economic adulteration of vegetable oils.A medida que la práctica de la adulteración de aceites vegetales se hace más sofisticada, las posibilidades de evitar la detección utilizando técnicas tradicionales como la cromatografía de gases en columna capilar aumentan. Una de las técnicas más poderosas que más se utilizan en los estudios de autentificación de alimentos es la espectrometría de masas de relaciones isotópicas, que utiliza diferencias en la abundancia natural de isótopos estables de elementos ligeros biológicos hidrógeno, nitrógeno, carbón, oxigeno y azufre para detectar fraude en los alimentos. La espectrometría de masas de relaciones isotópicas ha encontrado aplicación en la autentificación de una amplia gama de alimentos, incluyendo zumos de frutas, vinos, bebidas alcohólicas de alta graduación, miel, y en la detección de la adulteración de los compuestos aromáticos con sus análogos de origen sintético. Este trabajo

  4. Hydrogen isotope storage behavior of Zr1-xTixCo alloys

    International Nuclear Information System (INIS)

    Jat, Ram Avtar; Pati, Subhasis; Parida, S.C.; Agarwal, Renu; Mukerjee, S.K.

    2016-01-01

    Tritium storage properties similar to uranium make ZrCo as a suitable candidate material for storage, supply and recovery of hydrogen isotopes in various tritium facilities. Beside non-radioactive, nonpyrophoric at room temperature and higher storage capacity (H/f.u. up to 3, f.u. = ZrCo), it has been reported that upon repeated hydriding-dehydriding cycles, ZrCo undergoes dis-proportionation as per the reaction; ZrCo + H 2 ↔ ZrH 2 + ZrCo 2 . The present study is aimed to investigate the effect of Ti content on the hydrogen storage behavior of Zr 1-x Ti x Co alloys and the hydrogen isotope effect

  5. Equation-of-state for fluids at high densities-hydrogen isotope measurements and thermodynamic derivations

    International Nuclear Information System (INIS)

    Liebenberg, D.H.; Mills, R.L.; Bronson, J.C.

    1977-01-01

    Hydrogen isotopes play an important role in energy technologies, in particular, the compression to high densities for initiation of controlled thermonuclear fusion energy. At high densities the properties of the compressed hydrogen isotopes depart drastically from ideal thermodynamic predictions. The measurement of accurate data including the author's own recent measurements of n-H 2 and n-D 2 in the range 75 to 300 K and 0.2 to 2.0 GPa (2 to 20 kbar) is reviewed. An equation-of-state of the Benedict type is fit to these data with a double-process least-squares computer program. The results are reviewed and compared with existing data and with a variety of theoretical work reported for fluid hydrogens. A new heuristic correlation is presented for simplicity in predicting volumes and sound velocity at high pressures. 9 figures, 1 table

  6. Carbon/Hydrogen ratio determination in hydrocarbons and its mixtures by electron backscattering technique

    International Nuclear Information System (INIS)

    Padron, I.; Desdin, L.F.; Navarro, A.; Fuentes, M.

    1996-01-01

    A method carbon/hydrogen ratio (C/H) determination in hydrocarbons and its mixtures was improved using the electron backscattering technique. Besides the hetero atoms (S,O and N) influence in petroleum is studied for being able to determinate the C/H ratio in cuban petroleum with high sulphur contents

  7. Uncertainties achievable for uranium isotope-amount ratios. Estimates based on the precision and accuracy of recent characterization measurements

    International Nuclear Information System (INIS)

    Mathew, K.J.; Essex, R.M.; Gradle, C.; Narayanan, U.

    2015-01-01

    Certified reference materials (CRMs) recently characterized by the NBL for isotope-amount ratios are: (i) CRM 112-A, Uranium (normal) Metal Assay and Isotopic Standard, (ii) CRM 115, Uranium (depleted) Metal Assay and Isotopic Standard, and (iii) CRM 116-A, Uranium (enriched) Metal Assay and Isotopic Standard. NBL also completed re-characterization of the isotope-amount ratios in CRM 125-A, Uranium (UO 2 ) Pellet Assay, Isotopic, and Radio-chronometric Standard. Three different TIMS analytical techniques were employed for the characterization analyses. The total evaporation technique was used for the major isotope-amount ratio measurement, the modified total evaporation technique was used for both the major and minor isotope-amount ratios, and minor isotope-amount ratios were also measured using a Conventional technique. Uncertainties for the characterization studies were calculated from the combined TIMS data sets following the ISO Guide to the expression of uncertainty in measurement. The uncertainty components for the isotope-amount ratio values are discussed. (author)

  8. Dietary heterogeneity among Western industrialized countries reflected in the stable isotope ratios of human hair.

    Science.gov (United States)

    Valenzuela, Luciano O; Chesson, Lesley A; Bowen, Gabriel J; Cerling, Thure E; Ehleringer, James R

    2012-01-01

    Although the globalization of food production is often assumed to result in a homogenization of consumption patterns with a convergence towards a Western style diet, the resources used to make global food products may still be locally produced (glocalization). Stable isotope ratios of human hair can quantify the extent to which residents of industrialized nations have converged on a standardized diet or whether there is persistent heterogeneity and glocalization among countries as a result of different dietary patterns and the use of local food products. Here we report isotopic differences among carbon, nitrogen and sulfur isotope ratios of human hair collected in thirteen Western European countries and in the USA. European hair samples had significantly lower δ(13)C values (-22.7 to -18.3‰), and significantly higher δ(15)N (7.8 to 10.3‰) and δ(34)S (4.8 to 8.3‰) values than samples from the USA (δ(13)C: -21.9 to -15.0‰, δ(15)N: 6.7 to 9.9‰, δ(34)S: -1.2 to 9.9‰). Within Europe, we detected differences in hair δ(13)C and δ(34)S values among countries and covariation of isotope ratios with latitude and longitude. This geographic structuring of isotopic data suggests heterogeneity in the food resources used by citizens of industrialized nations and supports the presence of different dietary patterns within Western Europe despite globalization trends. Here we showed the potential of stable isotope analysis as a population-wide tool for dietary screening, particularly as a complement of dietary surveys, that can provide additional information on assimilated macronutrients and independent verification of data obtained by those self-reporting instruments.

  9. Identifying the change in atmospheric sulfur sources in China using isotopic ratios in mosses

    Science.gov (United States)

    Xiao, Hua-Yun; Tang, Cong-Guo; Xiao, Hong-Wei; Liu, Xue-Yan; Liu, Cong-Qiang

    2009-08-01

    A considerable number of studies on rainwater sulfur isotopic ratios (δ34Srain) have been conducted to trace sulfur sources at a large number of sites in the past. If longitudinal studies on the isotope composition of precipitation sulfate were conducted, it is possible to relate that to changes in sulfur emissions. But direct measurement needs considerable labor and time. So, in this study, sulfur isotopic ratios in rainwater and mosses were analyzed at Guiyang and Nanchang to evaluate the possibility of using mosses as a substitute for rainwater. We found that present moss sulfur isotopic ratios were comparable to those of present rainwater. Additionally, we investigated the changes of atmospheric sulfur sources and sulfur concentrations using an isotopic graphic analysis at five industrial cities, two forested areas, and two remote areas in China. Mosses in industrial cities show a wide range of δ34S values, with the highest occurring at Chongqing (+3.9‰) and the lowest at Guiyang (-3.1‰). But as compared to those in forested and remote areas, δ34S values of mosses in all the five industrial cities are lower. On the basis of isotopic comparisons between past rainwater (reported in the literature) and present mosses, in the plot of δ34Smoss versus δ34Srain, six zones indicating different atmospheric sulfur change are separated by the 1:1 line and δ34S values of potential sulfur sources. Our results indicate that atmospheric sulfur pollution in most of the industrial cities decreased, while at the two forested areas, no significant changes were observed, and a new anxiousness coming from new energy sources (e.g., oil) appeared in some cities. Studies on the change of ambient SO2 concentrations support these results.

  10. Dietary heterogeneity among Western industrialized countries reflected in the stable isotope ratios of human hair.

    Directory of Open Access Journals (Sweden)

    Luciano O Valenzuela

    Full Text Available Although the globalization of food production is often assumed to result in a homogenization of consumption patterns with a convergence towards a Western style diet, the resources used to make global food products may still be locally produced (glocalization. Stable isotope ratios of human hair can quantify the extent to which residents of industrialized nations have converged on a standardized diet or whether there is persistent heterogeneity and glocalization among countries as a result of different dietary patterns and the use of local food products. Here we report isotopic differences among carbon, nitrogen and sulfur isotope ratios of human hair collected in thirteen Western European countries and in the USA. European hair samples had significantly lower δ(13C values (-22.7 to -18.3‰, and significantly higher δ(15N (7.8 to 10.3‰ and δ(34S (4.8 to 8.3‰ values than samples from the USA (δ(13C: -21.9 to -15.0‰, δ(15N: 6.7 to 9.9‰, δ(34S: -1.2 to 9.9‰. Within Europe, we detected differences in hair δ(13C and δ(34S values among countries and covariation of isotope ratios with latitude and longitude. This geographic structuring of isotopic data suggests heterogeneity in the food resources used by citizens of industrialized nations and supports the presence of different dietary patterns within Western Europe despite globalization trends. Here we showed the potential of stable isotope analysis as a population-wide tool for dietary screening, particularly as a complement of dietary surveys, that can provide additional information on assimilated macronutrients and independent verification of data obtained by those self-reporting instruments.