Analysis isotope

In this equation the red O signifies oxygen enriched in Its mass 18 isotope analysis of isotopic enrichment was performed by mass spectrometry... 

Until about the 1990s, visible light played little intrinsic part in the development of mainstream mass spectrometry for analysis, but, more recently, lasers have become very important as ionization and ablation sources, particularly for polar organic substances (matrix-assisted laser desorption ionization, MALDI) and intractable solids (isotope analysis), respectively. 

For the naturally occurring elements, many new artificial isotopes have been made, and these are radioactive. Although these new isotopes can be measured in a mass spectrometer, this process could lead to unacceptable radioactive contamination of the instrument. This practical consideration needs to be considered carefully before using mass spectrometers for radioactive isotope analysis. 

In equation (3), the amount of Ar is obtained by isotope analysis (spiking with Ar). 

Isotope shifts for most elements are small in comparison with the bandwidth of the pulsed lasers used in resonance ionization experiments, and thus all the isotopes of the analyte will be essentially resonant with the laser. In this case, isotopic analysis is achieved with a mass spectrometer. Time-of flight mass spectrometers are especially well-suited for isotopic analysis of ions produced by pulsed resonance ionization lasers, because all the ions are detected on each pulse. 

SIMS has superb surface sensitivity since most of the secondary ions originate within a few nanometers of the surface and since high detection efficiency enables as little as 10 " of a monolayer to be detected for most elements. Because of its very high surface sensitivity, SIMS can be used to obtain depth profiles with exceptionally high depth resolution (<5 nm). Since the beam of primary ions can be focused to a small spot, SIMS can be used to characterize the surface of a sample with lateral resolution that is on the order of micrometers. Elements with low atomic numbers, such as H and He, can be detected, isotope analysis can be conducted, and images showing the distribution of chemical species across... 

Whether this is true or not, meteorites give us one definite piece of information. Isotopic analysis shows that each element in a meteorite has the same isotopes in the same percentages that this same element has on earth. The accepted explanation for this fact is that meteorites and the earth share a common origin and that they became separated after the elements were created. 

Stable Isotope Analysis, Bone Organic Fraction... 

A smaller number of individuals, 132 samples, was analyzed for stable isotopes of nitrogen. There were two objectives to the nitrogen isotope analysis 1) to determine the amount of animal protein in the diet and to look for variation between the sexes and 2) to determine when infants were weaned from the breast. These objectives were addressed by selecting at least ten individuals, when available, from a number of age classes. Figure 1.1 illustrates the age distribution of the sample. Table 1.3 shows the results of these analyses. Individual 5 N values are provided in Herring et al. (1998). 

The diet of the 19 century residents of Upper Canada was determined from historical sources and was reproduced in order to carry out chemical analysis. Stable carbon isotope analysis of food and human bone demonstrates that the spacing between the food eaten and the bone collagen is around 5.6%o. The value may vary slightly from this estimate since the latter is based on a reconstructed diet and a large number of bone samples, which exhibit a small amount of variation. Nevertheless, this empirically derived result agrees well with estimates from field (Vogel 1978), and laboratory studies (reviewed in Ambrose 1993). 

Ambrose, S.H. 1993 Isotopic analysis of paleodiets Methodological and interpretive considerations. In Sandford, M.K., ed., Investigations of Ancient Kmaan Tissue Chemical Analyses in Anthropology. Langhorne, PA, Gordon and Breach Science Publishers 59-130. 

Katzenberg, M.A. 1992 Advances in stable isotope analysis of prehistoric bones. In Saunders, S.R. and Katzenberg, M.A., eds.. The Skeletal Biology of Past Peoples Research Methods. New York, Wiley-Liss 105-120. 

Marino, B.D. and DeNiro, M.J. 1987 Isotopic analysis of archaeobotanicals to reconstruct past climates Effects of activities associated with food preparation on carbon, hydrogen and oxygen isotope ratios of plant cellulose. Journal of Archaeological Science 14 537-548. 

Tykot, R.H., van der Merwe, N.J. and Hammond, N. 1996 Stable isotope analysis of bone collagen, bone apatite, and tooth enamel in the reconstruction of human diet. A case study from Cuello, Belize. In Orna, M.V., ed., Archaeological Chemistry Organic, Inorganic, and Biochemical Analysis. ACS Symposium Series 625, Washington, DC, American Chemical Society 355-365. 

Ambrose, S.H. 1986 Stable carbon and nitrogen isotope analysis of human and animal diet in Mrica. Journal of Human Evolution 15 707-731. 

Isotopic analysis Methodological and interpretive considerations. In Sandford, M.K.,... 

Hobson, K.A. 1990 Stable isotope analysis of marbled murrelets evidence for fieshwater feeding and determination of trophic level. Condor 92 897-903. 

Katzenberg, M.A. 1989 Stable isotope analysis of archaeological faunal remains from Southern Ontario. Journal of Archaeological Science 16 319-329. 

Loader, N.J., Switsur, V.R. and Field, E.M. 1995 High-resolution stable isotope analysis of tree rings implications of microdendroclimatology for palaeoenvironmental research. The Holocene 5 457-460. 

Van Klinken, GJ. 1991 Dating and Dietary Reconstruction by Isotopic Analysis of Amino Acids in Fossil Bone Collagen—with Special Reference to the Caribbean. Ph.D. dissertation. University of Groningen, The Netherlands. 

Ambrose, S.H. 1990 Preparation and characterization of bone and tooth collagen for isotopic analysis. Journal of Archaeological Science 17 431 51. 

Prospects for stable isotopic analysis of Later Pleistocene honiinid diets in West Asia... 

Ambrose, S.H. 1998 Prospects for stable isotopic analysis of Later Pleistocene hominid diets in West Asia and Europe. In Akazawa, T., Aoki, K. and Bar-Yosef, O., eds.. Neanderthals and Modem Humans in West Asia. New York, Plenum Press 277-289. 

Lee-Thorp, J.A. and van der Merwe, N.J. 1987 Carbon isotope analysis of fossil bone apatite. South African Journal of Science 83 71-74. 

Sullivan, C.H. and Krueger, H.W. 1981 Carhon isotope analysis of separate chemical phases in modem and fossil hone. Nature 292 333-335. 

Two alternate methods have recently been developed and both are used in the present study. A laser probe analytical method provided the majority of the oxygen isotope data (see Kohn et al. 1996 for details on testing and developing the method). Laser probes were originally developed for the stable isotope analysis of silicates, oxides, and sulfides in ciystalline rocks (Crowe... 

Cerling, T. and Sharp, Z. 1996 Stable carbon and oxygen isotope analysis of fossil tooth enamel... 

Clayton, RN. and Mayeda, T.K. 1963 The use ofbromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis. Geochimica et CosmochimicaActa 27 43-52. 

O Neil, J.R., Roe, L.J., Reinhard, E. and Blake, R.E. 1994 A rapid and precise method of oxygen isotope analysis of biogenic phosphate. IsraelJournal of Earth Sciences 42 203-212. 

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