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Isotope

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Isotope - Free Register to Access Experts & Abstracts

Sebastian Götte - One of the best experts on this subject based on the ideXlab platform.

  • Isotope shift measurements of stable and short lived lithium Isotopes for nuclear charge radii determination
    Physical Review A, 2011
    Co-Authors: Wilfried Nörtershäuser, B A Bushaw, J A Behr, Göran Ewald, Jens Dilling, P. Bricault, G. W. F. Drake, M. Dombsky, R Sánchez, Sebastian Götte
    Abstract:

    Changes in the mean square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise Isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a laser spectroscopic approach to determine the charge radii of lithium Isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8-ms-lifetime Isotope with production rates on the order of only 10 000 atoms/s. The method was applied to all bound Isotopes of lithium including the two-neutron halo Isotope {sup 11}Li at the on-line Isotope separators at GSI, Darmstadt, Germany, and at TRIUMF, Vancouver, Canada. We describe the laser spectroscopic method in detail, present updated and improved values from theory and experiment, and discuss the results.

Frank Vanhaecke - One of the best experts on this subject based on the ideXlab platform.

  • Molybdenum Isotope enrichment by anion-exchange chromatography
    Journal of Analytical Atomic Spectrometry, 2014
    Co-Authors: Dmitry Malinovsky, Frank Vanhaecke
    Abstract:

    Stable enriched Isotopes with an abundance as close to 100% as possible are most desirable parent materials for preparing synthetic Isotope mixtures for calibration of mass spectrometers. In this study, we have examined the extent of Mo Isotope fractionation during anion-exchange chromatography and assessed the potential of this separation technique for further Isotope enrichment of commercially available isotopically enriched molybdenum. The 60 cm wide molybdenum adsorption band was eluted from a 1.8 m long (3 times 60 cm) chromatographic column, filled with strongly basic anion-exchange resin. It was observed that heavier Mo Isotopes were preferentially eluted from the resin, resulting in an enrichment of heavier Mo Isotopes at the front of the adsorption band and a corresponding depletion at the rear. An equilibrium Isotope effect between dissolved and resin-bound chemical forms of molybdenum appears to be the cause of the Mo Isotope fractionation observed. The height equivalent to a theoretical plate (HETP) was calculated to be 0.25 mm, while the separation factor (α = Rresin/Rsolution) was found to be 0.99998 per atomic mass unit. These results show that molybdenum can, in principle, be further enriched isotopically by anion-exchange chromatography in a laboratory environment. However, achieving the highest degree of enrichment was confirmed to be very laborious. It has been estimated that in order to reach an increase in the abundance of 98Mo Isotope from an original value of 98.2% to 99.9%, the molybdenum adsorption band would need to migrate over a distance of at least 400 m through the anion-exchange resin. Another interesting observation made in this study was that no mass-independent Isotope fractionation was observed for molybdenum as a result of chemical exchange reactions on the anion-exchange resin.

  • experimental study of mass independence of hg Isotope fractionation during photodecomposition of dissolved methylmercury
    Journal of Analytical Atomic Spectrometry, 2010
    Co-Authors: Dmitry Malinovsky, Luc Moens, Kris Latruwe, Frank Vanhaecke
    Abstract:

    Experiments modelling photolytic decomposition of methylmercury chloride in aqueous solutions of different chemical composition have been performed. Ion-exchange chromatographic separation using Chelex® 100 resin was used in order to separate methylmercury from inorganic mercury prior to the Isotope ratio measurements by solution nebulization multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). The performance of the chromatographic separation has been evaluated in terms of recovery of both methylmercury and inorganic Hg using synthetic solutions. Both mass-dependent and mass-independent fractionation of Hg Isotopes concomitant with the decomposition process have been observed. Mass-independent Hg Isotope fractionation (MIF) resulted in selective enrichment of 199Hg and 201Hg relative to the other Isotopes in the methylmercury molecules and has been attributed to the magnetic Isotope effect. The highest extent of MIF of Hg Isotopes, expressed as Δ199Hg and Δ201Hg values, has been observed in acidified solution with low concentration of total dissolved solids (TDS). Progressive decrease in Δ199Hg and Δ201Hg values in acidified solution with higher concentration of TDS, alkaline solutions of both low and high concentration of TDS, and in a solution of ascorbic acid has been attributed to suppression of the radical pair reaction mechanism, responsible for the occurrence of the magnetic Isotope effect, by substances acting as radical scavengers, such as OH− or ascorbic acid. The data obtained in this study demonstrate the significance of spin chemistry effects in the Isotope fractionation of mercury.

  • Variation in the isotopic composition of zinc in the natural environment and the use of zinc Isotopes in biogeosciences: a review
    Analytical and Bioanalytical Chemistry, 2008
    Co-Authors: Christophe Cloquet, Moritz F Lehmann, Jean Carignan, Frank Vanhaecke
    Abstract:

    Zinc (Zn) is a trace element that is, as a building block in various enzymes, of vital importance for all living organisms. Zn concentrations are widely determined in dietary, biological and environmental studies. Recent papers report on the first efforts to use stable Zn Isotopes in environmental studies, and initial results point to significant Zn Isotope fractionation during various biological and chemical processes, and thus highlight their potential as valuable biogeochemical tracers. In this article, we discuss the state-of-the-art analytical methods for isotopic analysis of Zn and the procedures used to obtain accurate Zn Isotope ratio results. We then review recent applications of Zn Isotope measurements in environmental and life sciences, emphasizing the mechanisms and causes responsible for observed natural variation in the isotopic composition of Zn. We first discuss the Zn Isotope variability in extraterrestrial and geological samples. We then focus on biological processes inducing Zn Isotope fractionation in plants, animals and humans, and we assess the potential of Zn Isotope ratio determination for elucidating sources of atmospheric particles and contamination. Finally, we discuss possible impediments and limitations of the application of Zn Isotopes in (geo-) environmental studies and provide an outlook regarding future directions of Zn Isotope research.

  • applicability of high resolution icp mass spectrometry for Isotope ratio measurements
    Analytical Chemistry, 1997
    Co-Authors: Frank Vanhaecke, Luc Moens, Richard Dams, Ioannis Papadakis, Philip D P Taylor
    Abstract:

    The present paper reports on the capability of high-resolution inductively coupled plasma mass spectrometry (HR-ICPMS) for the accurate and precise determination of Isotope ratios of which at least one of the Isotopes involved is spectrally interfered when measured at low resolution, using Cu as a typical example. When a commercially available Finnigan MAT Element high-resolution ICP−mass spectrometer operated at a resolution setting of 3000 is used, careful selection of the measurement conditions allows a 63Cu/65Cu or 206Pb/207Pb Isotope ratio precision of ∼0.1% (RSD for n = 10) at sufficiently high count rates (≥100 000 counts/s). In this work, Cu Isotope ratios were determined both in (i) an Antarctic sediment digest and in (ii) a human serum reference material. Even at the low Cu concentration level in the Antarctic sediment digests (∼10 μg/L), the 63Cu/65Cu Isotope ratio could be measured with an RSD of ≤0.6% (n = 5). Although both Isotopes involved were severely spectrally interfered when measured a...

Wilfried Nörtershäuser - One of the best experts on this subject based on the ideXlab platform.

  • Isotope shift measurements of stable and short lived lithium Isotopes for nuclear charge radii determination
    Physical Review A, 2011
    Co-Authors: Wilfried Nörtershäuser, B A Bushaw, J A Behr, Göran Ewald, Jens Dilling, P. Bricault, G. W. F. Drake, M. Dombsky, R Sánchez, Sebastian Götte
    Abstract:

    Changes in the mean square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise Isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a laser spectroscopic approach to determine the charge radii of lithium Isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8-ms-lifetime Isotope with production rates on the order of only 10 000 atoms/s. The method was applied to all bound Isotopes of lithium including the two-neutron halo Isotope {sup 11}Li at the on-line Isotope separators at GSI, Darmstadt, Germany, and at TRIUMF, Vancouver, Canada. We describe the laser spectroscopic method in detail, present updated and improved values from theory and experiment, and discuss the results.

R Sánchez - One of the best experts on this subject based on the ideXlab platform.

  • Isotope shift measurements of stable and short lived lithium Isotopes for nuclear charge radii determination
    Physical Review A, 2011
    Co-Authors: Wilfried Nörtershäuser, B A Bushaw, J A Behr, Göran Ewald, Jens Dilling, P. Bricault, G. W. F. Drake, M. Dombsky, R Sánchez, Sebastian Götte
    Abstract:

    Changes in the mean square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise Isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a laser spectroscopic approach to determine the charge radii of lithium Isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8-ms-lifetime Isotope with production rates on the order of only 10 000 atoms/s. The method was applied to all bound Isotopes of lithium including the two-neutron halo Isotope {sup 11}Li at the on-line Isotope separators at GSI, Darmstadt, Germany, and at TRIUMF, Vancouver, Canada. We describe the laser spectroscopic method in detail, present updated and improved values from theory and experiment, and discuss the results.

M. Dombsky - One of the best experts on this subject based on the ideXlab platform.

  • Isotope shift measurements of stable and short lived lithium Isotopes for nuclear charge radii determination
    Physical Review A, 2011
    Co-Authors: Wilfried Nörtershäuser, B A Bushaw, J A Behr, Göran Ewald, Jens Dilling, P. Bricault, G. W. F. Drake, M. Dombsky, R Sánchez, Sebastian Götte
    Abstract:

    Changes in the mean square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise Isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a laser spectroscopic approach to determine the charge radii of lithium Isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8-ms-lifetime Isotope with production rates on the order of only 10 000 atoms/s. The method was applied to all bound Isotopes of lithium including the two-neutron halo Isotope {sup 11}Li at the on-line Isotope separators at GSI, Darmstadt, Germany, and at TRIUMF, Vancouver, Canada. We describe the laser spectroscopic method in detail, present updated and improved values from theory and experiment, and discuss the results.