Gas source mass spectrometry

Gas-source mass spectrometry. Work on Se stable isotopes has a long history, dating back to the Ph.D. work of H. Roy Krouse around 1960. From 1960 to 1990, analyses were done by gas-source mass spectrometry using SeF (Krouse and Thode 1962). The sample Se was converted to Se(0), then reacted with Fj gas to produce SeF. This method required large quantities (e.g., tens of micrograms) of Se for measurements and thus was not widely applied. Recent continuous flow mass spectrometry methods could enable gas-source measurements on much smaller quantities, but will still use too much sample to compete with TIMS and MC-ICP-MS methods. 

This chapter focuses on selected developments and applications of mass spectrometry for the analysis of gases and volatile compounds relevant in inorganic mass spectrometry. A brief introduction to isotope ratio measurements by gas source mass spectrometry is presented in Section 8.3. 

Isotope Ratio Measurements by Gas Source Mass Spectrometry... 

S. Gas source mass spectrometry (GSMS) with electron impact (El) ion source produces nearly mono-energetic ions (similar to TIMS) and is an excellent tool for the high precision isotope analysis of light elements such as H, C, N and O, but also for S or Si.7,100,101 Precise and accurate measurements of isotope ratios have been carried out by gas source mass spectrometers with multiple ion collectors by a sample/standard comparison and the 8 values of isotope ratios were determined (see Equation 8.4). Electron impact ionization combined with mass spectrometry has been applied for elements which readily form gaseous compounds (e.g., C02 or S02) for the isotope analysis of carbon and sulfur, respectively). 

Recent advances in analytical instrumentation and methodology promise to add many more geochemical proxies to the palaeoceanographer s toolbox. MC-ICP-MS has opened up a number of isotopic systems previously considered intractable, such as zinc (which shows potential as a tracer of nutrient utilization Vance et al. 2006) and germanium, whose isotopic composition has recently been measured in biogenic opal (Rouxel et al. 2006). Meanwhile improvements in gas source mass spectrometry techniques now permit precise measurement of the abundance of C- 0 bonds in biogenic carbonate. C- 0 abundance shows promise as a palaeothermometer which, unlike 8 0, is independent of the stable isotope composition of seawater (Ghosh et al. 2006). 

Continuous flow-isotope ratio mass spectrometry Gas source mass spectrometry where sample and standard gases are transported using helium as a carrier gas into the mass spectrometer for measurement of isotopic ratios. 

Richter, S., Kuhn, H., Truyens, J. et al. (2013). Uranium hexafluoride (UF6) gas source mass spectrometry for certification of reference materials and nuclear safeguards measurements at IRMM, J. Anal. At. Spectrom. 28, 536-548. 

Most elements of the periodic table have been investigated for the presence of isotopic anomalies as part of various cosmochemical studies (Figure 10.3) and many have even been studied at great detail. For light elements that are either present as gases in samples or which are readily volatilized, such analyses are typically conducted by gas source mass spectrometry. In the past, isotopic analysis of metallic and metalloid elements were primarily carried out using either thermal ionization mass spectrometry (TIMS) or, for in situ measurements, secondary... 

Russell, R. D. Gas source mass spectrometry of trace leads from Sudbury, Ontario. Geochim. Cosmochim. Acta 28, 455—469 (1964). 

The particle flux that is part of the expanding corona of the Sun is known as the solar wind. The elemental and isotopic composition of the solar wind was studied by various space craft in the period 1965-1975, all of which carried electrostatic positive ion analysers. An ideal opportunity for further study was afforded by the Apollo mission to the Moon, in that aluminium foil collectors were exposed on the lunar surface in the Apollo 11-16 missions which were then analysed for the noble gases by gas source mass spectrometry on the returned A1 foil. 

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