Observations on the isotopic geochemistry of calcium

Corless, James T.

doi:10.1016/0012-821x(68)90027-7

Cited by 17 publications

(4 citation statements)

References 8 publications

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“…The total Ca concentration is precisely determined for instance by acid EDTA titration (ethylenediaminetetraacetic) in wet chemistry. The results obtained by neutron activation analysis showed large variations of up to 10 ‰ (Corless 1966(Corless , 1968, which were, however, not reproduced by subsequent studies.…”

Section: Neutron Activation Analysismentioning

confidence: 62%

“…INAA Mass dependent Ca isotope fractionation effects were also approached by methods other than mass spectrometry. One of the applied analytical methods was neutron activation analysis (INAA) (Corless 1966(Corless , 1968. The basic concept of neutron activation is that certain nuclides are selectively activated by neutron-radiation.…”

Section: Neutron Activation Analysismentioning

confidence: 99%

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Analytical Methods

1989

Lead Finishing in Semiconductor Devices: Soldering

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Despite the large relative mass difference between different Ca isotopes, the isotopic variability of Ca in natural materials is relatively small. Consequently, high-precision Ca isotope analyses are required to accurately resolve Ca isotope fractionation prior to data interpretation. This chapter summarises techniques which are successfully used to digest samples and to purify different types of sample material. The basic principles of different mass spectrometric methods for the accurate and precise determination of Ca isotope compositions are presented with a focus on thermal ionisation mass spectrometry (TIMS) and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). We also present an overview about other, less frequently applied techniques used so far. Additionally, we provide useful information on how to report Ca isotope data (e.g. different notations and reference materials) and explain how to convert literature data based on different reference materials and/or given in different notations.

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Section: Neutron Activation Analysismentioning

confidence: 62%

Section: Neutron Activation Analysismentioning

confidence: 99%

Analytical Methods

1989

Lead Finishing in Semiconductor Devices: Soldering

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“…Thus, most of the studies of meteorites, carbonate sediments, calcium‐silicate minerals, and organic substances that were performed at that time yielded no variations in calcium isotopic composition within the error of measurements. Nevertheless, some researchers (see, e.g., Corless, 1968; Coleman, 1971) reported small but significant deviations in calcium isotope composition in natural materials. Coleman (1971) achieved precision equivalent to 0.2% in the 40 Ca/ 44 Ca ratio generally (0.03% in the best case); such a precision was considered sufficient to determine K–Ca ages of mica samples.…”

Section: Analytical Methods For Precise Isotope Analyses Of Calciummentioning

confidence: 99%

Calcium isotope analysis by mass spectrometry

Boulyga

2009

Mass Spectrometry Reviews

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The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo‐ and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low‐abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075–1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. The present article discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. In Sections 2 and 3, mass spectrometric methods applied to precise stable isotope analysis and to the determination of 41Ca are described. Section 4 contains a short summary of selected applications, and includes tracer experiments and the potential use of biological isotope fractionation in medical studies, paleoclimatic and paleoceanographic, and other terrestrial as well as extraterrestrial investigations. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:685–716, 2010

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“…As a consequence, large isotope fractionation effects in an order of up to 22xcan be observed during ion exchange processes (Heumann, 1972;Heumann andSchiefer, 1980, 1981;Russell et al, 1978). Corless (1968) suggested that variations of Ca isotope ratios of 10x ( 48 Ca/(total Ca)) can also be caused by kinetic isotope fractionation introduced by biologically mediated processes. Skulan et al (1997) were the first who focused their attention on the biological control of the Ca isotopic composition.…”

Section: Introductionmentioning

confidence: 99%