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  • 1985-1989  (4)
  • Chemistry  (4)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 17 (1988), S. 139-143 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Instead of using the complete set of fundamental parameters for solving matrix effects in quantitative energy-dispersive x-ray fluorescence (EDXRF) analysis, some of them, such as excitation and detection efficiency and the dependence of Compton and Rayleigh scattered intensities on sample composition, were determined from a set of standards such as chemical compounds and pure elements. In this way all fundamental parameters except mass absorption coefficients were removed from the calculation procedure, which results in a much simpler formalism. The computer program COREX based on this principle and described in this paper is relatively simple and can run even on small microcomputers, while the overall error can be kept in the range of a few percent if the calibration procedure and sample preparation were performed carefully.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 14 (1985), S. 50-52 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A method for the calculation of interelement ‘empirical’ coefficients through the fundamental parameters method has been developed. The results of standard alloy analyses obtained in this way confirm the validity of this approach.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 16 (1987), S. 125-130 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The widely used formalism for quantitative XRF analysis based on the correction of characteristic line intensity for absorption effects is shown to be inadequate when thick samples with low total mass attenuation coefficients are analysed (biological samples, solutions, etc.). The geometry factor is not a constant function of the collimator's shape and dimensions, but it is found that in an analysed matrix it depends on the line energy and penetration depth. An experimental and a theoretical model for the determination of the geometrical correction are proposed and tested on a set of samples. The concentrations obtained are in excellent agreement with the values expected, whereas the model based on the correction of intensities only for absorption effects gives an error of at least 25% for thick samples.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 18 (1989), S. 73-76 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: It was shown that x-ray fluorescence is very suitable for following changes in trace element concentrations in the hair of pregnant women. Two hundred hair samples were analysed, mean concentrations for Cr, Mn, Fe, Cu and Zn were evaluated quarterly and their distribution according to weeks of pregnancy was determined. Possibilities of using longitudinal hair analysis with the purpose of following the concentrations of some particular microelements in the course of pregnancy are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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