Abstract: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 absol… Show more
The 3He/4He ratio in the atmosphere is known to be 1.34 × 10−6. For accurate measurement of low 3He concentrations, a certified reference material (CRM) with a low 3He/4He ratio is necessary. In this work, we produced a new 3He CRM of helium isotopic ratio standard by the gravimetric method with a 3He concentration similar to that of the atmospheric air. Previously, a helium isotope CRM with a 3He concentration of 3He/4He = 4743 μmol/mol was developed. Because 3He/4He ratio of atmospheric helium is much lower than this, we decided to produce a new 3He CRM of helium isotopic ratio and the previously prepared 3He CRM was diluted by the gravimetric method. The concentration of 3He in the high purity helium gas used for dilution was measured by comparing it with the newly prepared low 3He concentration CRMs.
The 3He/4He ratio in the atmosphere is known to be 1.34 × 10−6. For accurate measurement of low 3He concentrations, a certified reference material (CRM) with a low 3He/4He ratio is necessary. In this work, we produced a new 3He CRM of helium isotopic ratio standard by the gravimetric method with a 3He concentration similar to that of the atmospheric air. Previously, a helium isotope CRM with a 3He concentration of 3He/4He = 4743 μmol/mol was developed. Because 3He/4He ratio of atmospheric helium is much lower than this, we decided to produce a new 3He CRM of helium isotopic ratio and the previously prepared 3He CRM was diluted by the gravimetric method. The concentration of 3He in the high purity helium gas used for dilution was measured by comparing it with the newly prepared low 3He concentration CRMs.
This review covers advances in the analysis of air, water, plants, soils and geological materials by a range of atomic spectrometric techniques including atomic emission, absorption, fluorescence and mass spectrometry.
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