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High Precision Hf‐W Isotopic Measurements in Meteoritic Material Using Negative Thermal Ionisation Mass Spectrometry (NTIMS)
Author(s) -
Quitté Ghylaine,
Birck JeanLouis,
Capmas Françoise,
Allègre Claude J.
Publication year - 2002
Publication title -
geostandards newsletter
Language(s) - English
Resource type - Journals
eISSN - 1751-908X
pISSN - 0150-5505
DOI - 10.1111/j.1751-908x.2002.tb00883.x
Subject(s) - tungsten , mass spectrometry , thermal ionization mass spectrometry , analytical chemistry (journal) , extraction (chemistry) , chemistry , thermal ionization , silicate , materials science , ion , ionization , chromatography , metallurgy , electron ionization , organic chemistry
This paper presents a two‐stage anion‐exchange procedure for tungsten extraction, an improved mass spectrometric procedure for tungsten analysis and a simplified chemical separation and TIMS procedure for the determination of Hf concentrations. The chemical separation of tungsten is based on its complexing properties with HF and H 2 O 2 . The blank level for a sample size of 300 mg is about 80 pg for tungsten. The procedure is designed for the high sensitivity of negative thermal ionisation mass spectrometry (NTIMS) provided by the use of Mg oxide as an emitter on Ir filaments. Tungsten can be readily measured with a high precision in various meteoritical material and especially in small W‐poor silicate fractions. Samples containing as little as a few ng g ‐1 tungsten can be analysed reliably with this method.