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Preparation of Helium Isotope‐certified Reference Materials by Gravimetry
Author(s) -
Tshilongo James,
Min Deullae,
Lee Jin Bok,
Kim Jin Seog
Publication year - 2015
Publication title -
bulletin of the korean chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.237
H-Index - 59
ISSN - 1229-5949
DOI - 10.1002/bkcs.10114
Subject(s) - gravimetric analysis , isotope , helium , analytical chemistry (journal) , metrology , isotope dilution , chemistry , international system of units , mass spectrometry , isobaric process , certified reference materials , consistency (knowledge bases) , thermodynamics , chromatography , nuclear physics , physics , computer science , organic chemistry , detection limit , optics , artificial intelligence
An advanced gravimetric system was used to produce certified reference materials of mixtures of helium isotopes, traceable to the Système International d'Unitès ( SI unit) of moles. Critical factors in developing isotope reference mixtures include the purity assessment of the source gases before preparation, the weighing system used for gravimetric mixing, a well‐developed gas filling system, and internal consistency among the mixtures. Three artificial helium isotope reference mixtures were prepared with absolute isotope ratios, R ( 4 He / 3 He ), of 18.905 ± 0.036, 98.78 ± 0.21, and 209.82 ± 0.44 ( k = 1), respectively. The internal consistency between the mixtures was verified using a precision single‐focusing magnetic sector‐type mass spectrometer with a dynamic inlet system. The results showed that the proportions of the three reference isotope mixtures were well within the measurement uncertainty. The isotope reference mixtures were produced with the highest metrological uncertainty level.