WALCZYK, T and HEBEDA, EH and HEUMANN, KG (1991) OSMIUM ISOTOPE RATIO MEASUREMENTS BY NEGATIVE THERMAL IONIZATION MASS-SPECTROMETRY (NTI-MS) - IMPROVEMENT IN PRECISION AND ENHANCEMENT IN EMISSION BY INTRODUCING OXYGEN OR FREONS INTO THE ION-SOURCE. FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY, 341 (9). pp. 537-541. ISSN 0937-0633,
Full text not available from this repository.Abstract
A negative thermal ionization technique using a Faraday cup as detector is presented, which allows precise isotope ratio measurements of osmium. For the major isotopes the relative standard deviation is in the range of 0.004% to 0.07%. Sample amounts down to 1 ng were loaded as hexachloroosmic acid. From the results it is concluded that also sample amounts in the pg range will result in sufficient ion currents of OsO3-, avoiding an electron multiplier as detector. H2OSCl6 was chosen because this compound is the most suitable chemical form after separation of osmium from geological samples. The introduction of oxygen or freons into the ion source enhances the emission of OsO3- ions by a factor of up to more than ten. Ionization efficiencies of more than 30% are obtained by using oxygen. The stability of the ion current is better in the case of oxygen than in the case of freons. However, both compounds are stabilizing the high voltage potentials of the optical ion lenses in the ion source, a permanent problem in NTI-MS. The described isotope ratio measurement is an important improvement for Re/Os dating of terrestrial and extra-terrestrial samples.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ; |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:46 |
| URI: | https://pred.uni-regensburg.de/id/eprint/55128 |
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