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Jun Wang - One of the best experts on this subject based on the ideXlab platform.
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accurate determination of the absolute isotopic composition and Atomic Weight of molybdenum by multiple collector inductively coupled plasma mass spectrometry with a fully calibrated strategy
Analytical Chemistry, 2017Co-Authors: Panshu Song, Jun Wang, Tao Zhou, Tongxiang Ren, Yuanjing Zhou, Song WangAbstract:A fully calibrated strategy has been investigated for the first time for the accurate determination of absolute isotopic composition and Atomic Weight of molybdenum using multiple-collector inductively coupled plasma mass spectrometry. The correction for instrumental mass bias was performed using synthetic isotope mixtures, which were gravimetrically prepared with all of the seven high-purity and isotopically enriched molybdenum isotope materials together. Six natural molybdenum materials, including molybdenum standard solution NIST SRM 3134, were accurately measured and yielded the absolute isotopic composition (in atom %, k = 1) of 92Mo-14.690(18), 94Mo-9.173(6), 95Mo-15.865(5), 96Mo-16.666(3), 97Mo-9.588(4), 98Mo-24.307(16), and 100Mo-9.711(13). These isotopic data enable an Atomic Weight Ar(Mo) of 95.9466(34) (k = 2) to be calculated, which is slightly lower than the current standard Atomic Weight 95.95(1) and with a much improved uncertainty. The associated uncertainties were evaluated according to t...
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the absolute isotopic composition and Atomic Weight of ytterbium using multi collector inductively coupled plasma mass spectrometry and development of an si traceable ytterbium isotopic certified reference material
Journal of Analytical Atomic Spectrometry, 2015Co-Authors: Jun Wang, Tao Zhou, Tongxiang Ren, Yuanjing ZhouAbstract:We have determined the absolute isotopic composition of ytterbium in six varieties of (terrestrial source) materials based on calibrated mass spectrometry using multi-collector inductively coupled plasma mass spectrometry. Instrumental mass bias was corrected by measuring a series of mixture solutions, which were gravimetrically prepared with three high purity and isotopically enriched isotopes 171Yb, 172Yb and 174Yb. The isotopic compositions of three enriched isotope materials were accurately measured by means of total evaporation thermal ionization mass spectrometry. Six natural-like ytterbium materials including NIM GBW04623 and NIST SRM3166a, yielded the absolute isotopic composition (in at%) of 168Yb 0.12648(22), 170Yb 3.0280(19), 171Yb 14.239(5), 172Yb 21.789(5), 173Yb 16.119(3), 174Yb 31.881(8), and 176Yb 12.817(12). The new Atomic Weight of ytterbium was calculated to be 173.0417(5) (k = 2) based on these data. In addition, an ytterbium isotopic certified reference material in nitric acid solution (GBW04623) was developed by using a metrological approach, which would be proposed as the delta zero reference for ytterbium.
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precise determination of the absolute isotopic abundance ratio and the Atomic Weight of chlorine in three international reference materials by the positive thermal ionization mass spectrometer cs2cl graphite method
Analytical Chemistry, 2012Co-Authors: Haizhen Wei, Jun Wang, Shaoyong Jiang, Yingkai Xiao, Chongguang LuoAbstract:Because the variation in chlorine isotopic abundances of naturally occurring chlorine bearing substances is significant, the IUPAC Inorganic Chemistry Division, Commission on Isotopic Abundances and Atomic Weights (CIAAW-IUPAC) decided that the uncertainty of Atomic Weight of chlorine (Ar(Cl)) should be increased so that the implied range was related to terrestrial variability in 1999 (Coplen, T. B. Atomic Weights of the elements 1999 (IUPAC Technical Report), Pure Appl. Chem.2001, 73(4), 667–683; and then, it emphasized that the standard Atomic Weights of ten elements including chlorine were not constants of nature but depend upon the physical, chemical, and nuclear history of the materials in 2009 (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359–396). According to the agreement by CIAAW that an Atomic Weight could be defined for one specified sample of terrestrial origin (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359–396), the absolute isotope ratios and Atomic Weight of ch...
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absolute isotopic composition and Atomic Weight of selenium using multi collector inductively coupled plasma mass spectrometry
International Journal of Mass Spectrometry, 2011Co-Authors: Jun Wang, Tao Zhou, Tongxiang Ren, Mo-tian ZhaoAbstract:Abstract The isotopic composition of selenium was measured with high precision using a collision cell multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). Gravimetric synthetic mixtures prepared from three highly enriched isotope of 76Se, 78Se and 82Se with well defined purity were used to calibrate a MC-ICP-MS. Measurements of seven various natural selenium materials including Se NIST SRM 3149 yielded the absolute isotopic composition (in at.%) of 74Se 0.8623(38), 76Se 9.228(10), 77Se 7.5975(50), 78Se 23.693(12), 80Se 49.800(17) and 82Se 8.8188(85). The new Atomic Weight of selenium was calculated as 78.9711(9).
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absolute isotopic composition and Atomic Weight of neodymium using thermal ionization mass spectrometry
Rapid Communications in Mass Spectrometry, 2005Co-Authors: Mo-tian Zhao, Jun Wang, Tao Zhou, Xiang Fang, Chunhua GuoAbstract:Synthetic mixtures prepared gravimetrically from highly enriched isotopes of neodymium in the form of oxides of well-defined purity were used to calibrate a thermal ionization mass spectrometer. A new error analysis was applied to calculate the final uncertainty of the Atomic Weight value. Measurements on natural neodymium samples yielded an absolute isotopic composition of 27.153(19) Atomic percent (at.%) 142Nd, 12.173(18) at.% 143Nd, 23.798(12) at.% 144Nd, 8.293(7) at.% 145Nd, 17.189(17) at.% 146Nd, 5.756(8) at.% 148Nd, and 5.638(9) at.% 150Nd, and the Atomic Weight of neodymium as 144.2415(13), with uncertainties given on the basis of 95% confidence limits. No isotopic fractionation was found in terrestrial neodymium materials.
Juris Meija - One of the best experts on this subject based on the ideXlab platform.
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Interpreting and propagating the uncertainty of the standard Atomic Weights (IUPAC Technical Report)
Pure and Applied Chemistry, 2018Co-Authors: Antonio Possolo, Juris Meija, Adriaan M. H. Van Der Veen, D. Brynn HibbertAbstract:AbstractIn 2009, the Commission on Isotopic Abundances and Atomic Weights (CIAAW) of the International Union of Pure and Applied Chemistry (IUPAC) introduced the interval notation to express the standard Atomic Weights of elements whose isotopic composition varies significantly in nature. However, it has become apparent that additional guidance would be helpful on how representative values should be derived from these intervals, and on how the associated uncertainty should be characterized and propagated to cognate quantities, such as relative molecular masses. The assignment of suitable probability distributions to the Atomic Weight intervals is consistent with the CIAAW’s goal of emphasizing the variability of the Atomic Weight values in nature. These distributions, however, are not intended to reflect the natural variability of the abundances of the different isotopes in the earth’s crust or in any other environment. Rather, they convey states of knowledge about the elemental composition of “normal” materials generally, or about specific classes of such materials. In the absence of detailed knowledge about the isotopic composition of a material, or when such details may safely be ignored, the probability distribution assigned to the standard Atomic Weight intervals may be taken as rectangular (or, uniform). This modeling choice is a reasonable and convenient default choice when a representative value of the Atomic Weight, and associated uncertainty, are needed in calculations involving Atomic and relative molecular masses. When information about the provenance of the material, or other information about the isotopic composition needs to be taken into account, then this distribution may be non-uniform. We present several examples of how the probability distribution of an Atomic Weight or relative molecular mass may be characterized, and also how it may be used to evaluate the associated uncertainty.
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determination of the Atomic Weight of 28si enriched silicon for a revised estimate of the avogadro constant
Analytical Chemistry, 2012Co-Authors: Lu Yang, Zoltan Mester, Ralph E Sturgeon, Juris MeijaAbstract:The much anticipated overhaul of the International System of Units (SI) will result in new definitions of base units in terms of fundamental constants. However, redefinition of the kilogram in terms of the Planck constant (h) cannot proceed without consistency between the Avogadro and Planck constants, which are both related through the Rydberg constant. In this work, an independent assessment of the Atomic Weight of silicon in a highly enriched 28Si crystal supplied by the International Avogadro Coordination (IAC) was performed. This recent analytical approach, based on dissolution with NaOH and its isotopic characterization by multicollector inductively coupled plasma mass spectrometry, is critically evaluated. The resultant Atomic Weight Ar(Si) = 27.976 968 39(24)k=1 differs significantly from the most recent value of Ar(Si) = 27.976 970 27(23)k=1. Using the results generated herein for Ar(Si) along with other IAC measurement results for mass, volume, and the lattice spacing, the estimate of the Avogad...
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resolving the germanium Atomic Weight disparity using multicollector icpms
Analytical Chemistry, 2010Co-Authors: Lu Yang, Juris MeijaAbstract:Two most recent mass spectrometric measurements of natural isotopic composition germanium gave discordant Ge Atomic Weight values of 72.6276(64)k=2 and 72.6390(69)k=2, respectively, a decade ago. Each measurement was performed with a different mass spectrometry platform, gas source isotope ratio mass spectrometry and thermal ionization mass spectrometry, respectively. Herein we report results obtained by multicollector inductively coupled plasma mass spectrometry yielding an Atomic Weight of germanium 72.6296(19)k=2 which is in support of the upcoming 2009 Standard Atomic Weight adjustment by IUPAC. Germanium isotope ratios were calibrated using a regression mass bias correction model and NIST SRM 994 gallium isotopic reference material. In this model, no assumptions are made regarding the mass bias differences between gallium and germanium or between the isotopes of germanium. Isotope ratios of 0.5620(21), 0.7515(16), 0.2125(7), and 0.2121(12) were obtained for n(70Ge)/n(74Ge), n(72Ge)/n(74Ge), n(73Ge)/n...
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certification of natural isotopic abundance inorganic mercury reference material nims 1 for absolute isotopic composition and Atomic Weight
Journal of Analytical Atomic Spectrometry, 2010Co-Authors: Juris Meija, Lu Yang, Ralph E Sturgeon, Zoltan MesterAbstract:A candidate reference material of natural isotopic composition for inorganic mercury has been characterized by the Institute for National Measurement Standards of the National Research Council Canada. The material, designated NIMS-1 (natural inorganic mercury standard) is certified for isotope ratios, isotopic abundances and Atomic Weight of mercury. The certification was achieved using multi-collector ICP-MS based on a state-of-the-art regression model for calibration. The certified isotopic composition is x196 = 0.001 55(4), x198 = 0.100 38(10), x199 = 0.169 38(9), x200 = 0.231 38(6), x201 = 0.131 70(12), x202 = 0.297 43(9) and x204 = 0.068 18(6) with the corresponding Atomic Weight of mercury Ar(Hg) = 200.5924(8). Values are presented in a concise notation whereby the expanded uncertainty with a coverage factor of two is given in parenthesis next to the least significant digits to which it applies. A full disclosure of all raw data pertinent to certification is presented in order to afford a fully transparent process. Care was taken to ensure high metrological quality in the evaluation of the accuracy and the uncertainty of the certified results. In this regard, it is superior to the best measurement from a single terrestrial source as currently recognized by IUPAC. Considering the known natural variations of Hg isotopic composition, we propose 200.592(3) as a revised assessment of the standard Atomic Weight of mercury.
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Atomic Weight uncertainty calculation from isotopic composition of the elements
Metrologia, 2008Co-Authors: Juris Meija, Zoltan MesterAbstract:The raison d'etre for this paper is to outline mathematical tools for evaluating uncertainties of Atomic Weights from those of isotopic abundances despite the absence of information on isotopic abundance correlations—a task usually deemed impossible for elements with more than three stable isotopes.
Tao Zhou - One of the best experts on this subject based on the ideXlab platform.
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accurate determination of the absolute isotopic composition and Atomic Weight of molybdenum by multiple collector inductively coupled plasma mass spectrometry with a fully calibrated strategy
Analytical Chemistry, 2017Co-Authors: Panshu Song, Jun Wang, Tao Zhou, Tongxiang Ren, Yuanjing Zhou, Song WangAbstract:A fully calibrated strategy has been investigated for the first time for the accurate determination of absolute isotopic composition and Atomic Weight of molybdenum using multiple-collector inductively coupled plasma mass spectrometry. The correction for instrumental mass bias was performed using synthetic isotope mixtures, which were gravimetrically prepared with all of the seven high-purity and isotopically enriched molybdenum isotope materials together. Six natural molybdenum materials, including molybdenum standard solution NIST SRM 3134, were accurately measured and yielded the absolute isotopic composition (in atom %, k = 1) of 92Mo-14.690(18), 94Mo-9.173(6), 95Mo-15.865(5), 96Mo-16.666(3), 97Mo-9.588(4), 98Mo-24.307(16), and 100Mo-9.711(13). These isotopic data enable an Atomic Weight Ar(Mo) of 95.9466(34) (k = 2) to be calculated, which is slightly lower than the current standard Atomic Weight 95.95(1) and with a much improved uncertainty. The associated uncertainties were evaluated according to t...
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the absolute isotopic composition and Atomic Weight of ytterbium using multi collector inductively coupled plasma mass spectrometry and development of an si traceable ytterbium isotopic certified reference material
Journal of Analytical Atomic Spectrometry, 2015Co-Authors: Jun Wang, Tao Zhou, Tongxiang Ren, Yuanjing ZhouAbstract:We have determined the absolute isotopic composition of ytterbium in six varieties of (terrestrial source) materials based on calibrated mass spectrometry using multi-collector inductively coupled plasma mass spectrometry. Instrumental mass bias was corrected by measuring a series of mixture solutions, which were gravimetrically prepared with three high purity and isotopically enriched isotopes 171Yb, 172Yb and 174Yb. The isotopic compositions of three enriched isotope materials were accurately measured by means of total evaporation thermal ionization mass spectrometry. Six natural-like ytterbium materials including NIM GBW04623 and NIST SRM3166a, yielded the absolute isotopic composition (in at%) of 168Yb 0.12648(22), 170Yb 3.0280(19), 171Yb 14.239(5), 172Yb 21.789(5), 173Yb 16.119(3), 174Yb 31.881(8), and 176Yb 12.817(12). The new Atomic Weight of ytterbium was calculated to be 173.0417(5) (k = 2) based on these data. In addition, an ytterbium isotopic certified reference material in nitric acid solution (GBW04623) was developed by using a metrological approach, which would be proposed as the delta zero reference for ytterbium.
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absolute isotopic composition and Atomic Weight of selenium using multi collector inductively coupled plasma mass spectrometry
International Journal of Mass Spectrometry, 2011Co-Authors: Jun Wang, Tao Zhou, Tongxiang Ren, Mo-tian ZhaoAbstract:Abstract The isotopic composition of selenium was measured with high precision using a collision cell multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). Gravimetric synthetic mixtures prepared from three highly enriched isotope of 76Se, 78Se and 82Se with well defined purity were used to calibrate a MC-ICP-MS. Measurements of seven various natural selenium materials including Se NIST SRM 3149 yielded the absolute isotopic composition (in at.%) of 74Se 0.8623(38), 76Se 9.228(10), 77Se 7.5975(50), 78Se 23.693(12), 80Se 49.800(17) and 82Se 8.8188(85). The new Atomic Weight of selenium was calculated as 78.9711(9).
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absolute isotopic composition and Atomic Weight of neodymium using thermal ionization mass spectrometry
Rapid Communications in Mass Spectrometry, 2005Co-Authors: Mo-tian Zhao, Jun Wang, Tao Zhou, Xiang Fang, Chunhua GuoAbstract:Synthetic mixtures prepared gravimetrically from highly enriched isotopes of neodymium in the form of oxides of well-defined purity were used to calibrate a thermal ionization mass spectrometer. A new error analysis was applied to calculate the final uncertainty of the Atomic Weight value. Measurements on natural neodymium samples yielded an absolute isotopic composition of 27.153(19) Atomic percent (at.%) 142Nd, 12.173(18) at.% 143Nd, 23.798(12) at.% 144Nd, 8.293(7) at.% 145Nd, 17.189(17) at.% 146Nd, 5.756(8) at.% 148Nd, and 5.638(9) at.% 150Nd, and the Atomic Weight of neodymium as 144.2415(13), with uncertainties given on the basis of 95% confidence limits. No isotopic fractionation was found in terrestrial neodymium materials.
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absolute measurements of neodymium isotopic abundances and Atomic Weight by mc icpms
International Journal of Mass Spectrometry, 2005Co-Authors: Mo-tian Zhao, Jun Wang, Tao Zhou, Fang XiangAbstract:Abstract Gravimetric synthetic mixtures prepared from highly enriched isotopes of neodymium in the form of oxides of well-defined purity were used to calibrate a multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). Measurements on natural neodymium samples yielded an absolute isotopic composition 27.147(20) at.% 142 Nd, 12.182(21) at.% 143 Nd, 23.803(14) at.% 144 Nd, 8.297(6) at.% 145 Nd, 17.190(13) at.% 146 Nd, 5.755(8) at.% 148 Nd, 5.626(10) at.% 150 Nd, and the Atomic Weight of neodymium as 144.2409(17) both with an uncertainty given on the basis of 95% confidence limit. No isotopic fractionation was found in terrestrial neodymium materials. Thermal ionization mass spectrometry (TIMS) analyses were carried on the same samples measured by MC-ICPMS and the essentially identical results were obtained, both for the abundances and the Atomic Weights.
P. De Bièvre - One of the best experts on this subject based on the ideXlab platform.
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measurement of the isotopic composition and Atomic Weight of an isotopic reference material of platinum irmm 010
Analytica Chimica Acta, 2002Co-Authors: C Wolff S J Briche, P. De Bièvre, Michael Berglund, Andrea Held, P D P TaylorAbstract:Abstract An isotopic reference material (IRM), IRMM-010, was prepared as a metallic platinum wire and certified for isotopic composition of platinum. The measurements were carried out with a quadrupole inductively coupled plasma mass spectrometer (ICP-MS) in peak jumping mode using a secondary electron multiplier as detector. Five synthetic isotope mixtures with certified isotope amount ratios of n(196Pt)/n(195Pt) were prepared in order to calibrate the measurements. The synthetic isotope mixtures, the natural platinum reference material as well as the isotopically enriched materials were measured in a 2% HNO3 and 2% H2O2 matrix in order to reduce memory effects during the measurements. These measurements resulted in certified isotope amount ratios and isotopic composition of a platinum reference material with natural isotopic composition. The relative abundances of the different platinum isotopes were determined as: 0.0117±0.0012 amount % of 190Pt, 0.782±0.016 amount % of 192Pt, 32.86±0.27 amount % of 194Pt, 33.77+0.16 amount % of 195Pt, 25.21+0.23 amount % of 196Pt, and 7.356±0.087 amount % of 198Pt. This lead to an Atomic Weight equal to 195.0844±0.0058 for this material. The purity of IRMM-010 was measured, the total impurity was found to be 140±140 μg·g−1. Uncertainties are expanded combined uncertainties expressed with a coverage factor k=2.
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Isotope-abundance variations of selected elements (IUPAC Technical Report)
Pure and Applied Chemistry, 2002Co-Authors: Tyler B. Coplen, P. De Bièvre, H. S. Peiser, John Karl Böhlke, T. Ding, Norman E. Holden, Jessica A. Hopple, H. R. Krouse, Andrée Lamberty, Kinga ReveszAbstract: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 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.
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calibrated measurements of the isotopic composition and Atomic Weight of the natural li isotopic reference material irmm 016
International Journal of Mass Spectrometry and Ion Processes, 1997Co-Authors: P D P Taylor, Michael Berglund, P. De BièvreAbstract:The isotope abundance ratio of lithium in the Li isotopic reference material IRMM-016 was redetermined by thermal ionisation mass spectrometry by means of synthetic isotope mixtures. This resulted in an absolute ratio n(6Li)/n(7Li) of 0.08212 ± 0.00028, and corresponding isotope abundances of 7.589 ± 0.024 amount % 6Li, 92.411 ± 0.024 amount % 7Li and an Atomic Weight of lithium of 6.94005 ± 0.00024. Uncertainties are expanded uncertainties using a coverage factor of two.
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The chemical preparation and characterization of specimens for "absolute" measurements of the molar mass of an element, exemplified by silicon, for redeterminations of the Avogadro constant
Metrologia, 1995Co-Authors: P. De Bièvre, G. Lenaers, T. J. Murphy, H. S. Peiser, S ValkiersAbstract:The chemical steps needed to prepare specimens for "absolute" Atomic-Weight [(mean) relative Atomic mass] determinations are outlined and discussed in detail for the Atomic Weight of silicon, Ar (Si), as recently measured for a redetermination of the Avogadro constant. The estimated combined uncertainties arising from the chemical procedures in that Ar (Si) measurement are shown to be almost equal to those from the associated mass-spectrometric measurements.
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an assessment of the reliability of Atomic Weight data based on successive evaluations between 1967 and 1993
Journal of Physical and Chemical Reference Data, 1994Co-Authors: P. De Bièvre, H. S. PeiserAbstract:The reliability of the (standard) Atomic‐Weight (mean Atomic mass) values is quantified based on the analysis of changes made from published improved measurements as they become available for each periodic evaluation. This numerical analysis tests the evaluation procedures and the current reliability of the tables published by the International Union of Pure and Applied Chemistry. One instance of faulty evaluation is highlighted. The post facto test of past performance of evaluations might under appropriate conditions also serve for other data sets such as the fundamental constants of physics or property data for pure elements. §
Chunhua Guo - One of the best experts on this subject based on the ideXlab platform.
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absolute isotopic composition and Atomic Weight of neodymium using thermal ionization mass spectrometry
Rapid Communications in Mass Spectrometry, 2005Co-Authors: Mo-tian Zhao, Jun Wang, Tao Zhou, Xiang Fang, Chunhua GuoAbstract:Synthetic mixtures prepared gravimetrically from highly enriched isotopes of neodymium in the form of oxides of well-defined purity were used to calibrate a thermal ionization mass spectrometer. A new error analysis was applied to calculate the final uncertainty of the Atomic Weight value. Measurements on natural neodymium samples yielded an absolute isotopic composition of 27.153(19) Atomic percent (at.%) 142Nd, 12.173(18) at.% 143Nd, 23.798(12) at.% 144Nd, 8.293(7) at.% 145Nd, 17.189(17) at.% 146Nd, 5.756(8) at.% 148Nd, and 5.638(9) at.% 150Nd, and the Atomic Weight of neodymium as 144.2415(13), with uncertainties given on the basis of 95% confidence limits. No isotopic fractionation was found in terrestrial neodymium materials.