Mass spectrometry isotope patterns

Figure 7. A few examples of isotopic patterns of Ne, Ti and heavy elements in SiC and graphite grains are displayed. Absolute ratios are plotted for Ne (a) whereas abundance ratios relative to solar wind composition are plotted for Kr (c) and Xe (f). The remaining elements are plotted as %o deviations from laboratory standards. The data have been obtained on bulk SiC separates by traditional mass spectrometry for Ne (Jungck and Eberhardt 1979), Kr (Ott et al. 1988 Lewis et al. 1994), Sr, Ba (Ott and Begemann 1990 Prombo et al. 1993) and Nd (Richter 1995). SIMS techniques (caption continued on facing page)...

Nance WB, Taylor SR (1976) Rare earth element patterns and crustal evolution—I. Australian post-Archean sedimentary rocks. Geochim Cosmochim Acta 40 1539-1551 Nishio Y, Nakai S (2002) Accurate and precise lithium isotopic determinations of igneous rock samples using multi-collector inductively coupled plasma mass spectrometry. Anal Chim Acta 456 271-281 Nishio Y, Nakai S, Hirose K, Ishii T, Sano Y (2002) Li isotopic systematics of volcanic rocks in marginal basins. Geochim Cosmochim Acta 66 A556... 

The development of surface analytical techniques such as LA-ICP-MS, GDMS and SIMS focuses on improvements to sensitivity and detection limits in order to obtain precise and accurate analytical data. With respect to surface analytical investigations, an improvement of spatial and depth resolution is required, e.g., by the establishment of a near field effect or the apphcation of fs lasers in LA-ICP-MS. There is a need for the improvement of analytical techniques in the (j,m and nm range, in depth profiling analysis and especially in imaging mass spectrometry techniques to perform surface analyses faster and provide more accurate data on different materials to produce quantitative 3D elemental, isotopic and molecular distribution patterns of increased areas of interest with high spatial and depth resolution over an acceptable analysis time. 

These same six samples were also analyszed by inductively coupled plasma-mass spectrometry (ICP-MS) to determine if the same element patterns detected in the EMPA analysis could be observed with a less labor intensive method. ICP-MS works in a similar manner as TIMS, expect the sample is dissolved and injected into a plasma flame in order to atomize and ionize the sample. Isotopes ratios can be determined in this manner, but generally the precision is less than with TIMS. 

De Maio, W., Hoffmann, M., Carbonara, M., Moore, R., Mutlib, A., and Talaat, R. E. (2008). Identification of drug metabolites by UPLC-MS with isotope pattern directed mass chromatograms and UPLC with radioactivity flow detection. In Proceedings of the 56th ASMS Conference on Mass Spectrometry and Allied Topics. ASMS, Denver, CO. 

McGibbon, G. A. (2008). Information extraction from full-scan LC/MS data using isotope patterns. In Proceedings of the 56th ASMS Conference on Mass Spectrometry and Allied Topics, Denver, CO. 

It has been shown by mass spectrometry that the deuteration of C60 leads to products richer in deuterium content in comparison to the hydrogenation which instead leads almost exclusively to C60H36 (Taylor 1999 Darwish et al. 1995). However, the spectra in Fig. 7.3 show that C60H36 and its deuterated analogous display the same band pattern apart the discussed isotopic shift and hence it is reasonable to state that C60D36 has been obtained and studied. This observation has been made also by other authors who have used also Raman in addition to FT-IR spectroscopy (Meletov et al 2001). 

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