Mass spectrometry, for isotope ratios

Vanhaecke F., Moens L. and Dams R. (1997) Applicability of high-resolution ICP-mass spectrometry for isotope ratio measurements, Anal Chem 69 268-273. 

Wieser, M.E. and Schwieters, J.B. (2005) The development of multiple collector mass spectrometry for isotope ratio measurements. Int. J. Mass Spectrom., 242, 97-115. 

Prosser, S.J. A novel magnetic sector mass spectrometer for isotope ratio determination of light gases. Int. J. of Mass Spectrometry and Ion Processes. 125,1993,241-266. 

Correction of Instrumental Mass Discrimination for Isotope Ratio Determination with Multi-Collector Inductively Coupled Plasma Mass Spectrometry... 

Authenticity evaluation has recently received increased attention in a number of industries. The complex mixtures involved often require very high resolution analyses and, in the case of determining the authenticity of natural products, very accurate determination of enantiomeric purity. Juchelka et al. have described a method for the authenticity determination of natural products which uses a combination of enantioselective multidimensional gas chromatography with isotope ratio mass spectrometry (28). In isotope ratio mass spectrometry, combustion analysis is combined with mass spectrometry, and the ratio of the analyte is measured versus a... 

Merritt DA, KH Freeman, MP Ricci, SA Studley, JM Hayes (1995) Performance and optimization of a combustion interface for isotope ratio monitoring gas chromatography/mass spectrometry. Anal Chem 67 2461-2473. 

Krummen, M., Hilkert, A. W., Juchelka, D., Duhr, A., Schluter, H. J. and Pesch, R. (2004) A new concept for isotope ratio monitoring liquid chromatography/mass spectrometry. Rapid Communications in Mass Spectrometry 18, 2260 2266. 

Ricci, M. P., Merritt, D. A., Freeman, K. H. and Hayes, J. M. (1994) Acquisition and processing of data for isotope ratio monitoring mass spectrometry. Organic Geochemistry 21, 561 571. 

The measurements that have been made at Rochester and the experience that has been gathered over the years on the operation of sputter ion sources [38] indicate that an analytical tool of unprecedented sensitivity and accuracy for isotopic ratio determinations can be constructed by coupling SIMS technology with the new accelerator technique. The only difference in principle between the experiments that have been conducted to date and the technique as it would be applied in secondary ion mass spectrometry is that the primary beam of cesium would be focussed to a fine probe of pm dimensions rather than the spot diameters of approximately 1 mm that have been used to date. 

Deuterium nmr spectroscopy has been utilized for the last decade to determine large (primary deuterium) KIEs in reactions with isotopes present at the natural abundance level (Pascal et al., 1984,1986 Zhang, 1988). A great advantage of this approach is that labelled materials do not have to be synthesized. Neither is there any need for selective degradation procedures, which are often necessary to produce the molecules of low mass, e.g. C02, acceptable for isotope ratio mass spectrometry. Moreover, the KIEs for several positions can be determined from one sample. However, until quite recently the relatively low precision of the nmr integrations that are used for the quantitative assessment of the amount of deuterium at specific molecular sites has limited the applicability of this technique for determining small (secondary deuterium) KIEs. 

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)...

Taylor SR, McLennan SM (1985) The Continental Crust Its Composition and Evolution. Blackwell, Boston Tuit CB, Ravizza G (2003) The marine distribution of molybdenum. Geochim Cosmochim Acta 67 A4950 Tumlund JR, Keyes WR, Peiffer GL (1993) Isotope ratios of molybdenum determined by thermal ionization mass spectrometry for stable isotope studies of molybdenum metabolism in humans. Anal Chem 65 1717-1722... 

An excellent possibility for quantifying analytical data in inorganic mass spectrometry is isotope dilution analysis (IDA) based on more precise isotope ratio measurements. IDA uses highly enriched isotope spikes of analytes of known concentration for calibration and is the method of choice if a high accuracy for element concentrations is required. The principles and applications of this method will be discussed below. 

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. 

Of all the different mass spectrometric techniques for isotope analysis (such as ICP-MS, LA-ICP-MS, TIMS, GDMS, AMS, SIMS, RIMS and isotope ratio mass spectrometry of gases), the greatest proportion of pubhshed papers today concern ICP-MS with single and multiple ion collection.19 Due to its benefits, ICP-MS has now become a widely accepted method for isotope analysis and allows isotope ratios to be measured in a short time with good accuracy and precision.9,19,75 78 As discussed above, as a powerful and universal tool, ICP-MS has opened up new applications for isotope ratio measurements of elements with a high first ionization potential, which are difficult to analyze with TIMS (such as Mo, Hf, Fe). Of all the heavy metals studied, uranium was favoured by ICP-MS and LA-ICP-MS. 

Multiple Ion Collector Mass Spectrometry for High Precision Isotope Ratio Measurements... 

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