Influence of chemical environment on the analysis of X-ray spectra of thick pellet samples containing 3d transition metal compounds

Abstract

Nowadays quantitative analysis in energy dispersive X-ray Emission Spectroscopy is usually performed by the "fundamental parameter approach". Such an approach generally relies upon a good knowledge of fundamental physical parameters. As a rule none of the algorithms in use by laboratories performing routine analysis account for possible chemical effects on X-ray intensity ratios or energies. Here we tested the possible influence of such practice on reliability in the routine analysis of thick pellet samples containing transition metal compounds. A number of samples were prepared by mixing various proportions of MnO 2 , KMnO 4 , and Co 3 O 4 (sets A-B) or Cr 2 O 3 , K 2 Cr 2 O 7 , and Fe 2 O 3 (C-D). The samples were irradiated by 2 MeV proton beams and proton induced X-ray emission spectra were analyzed by a "fundamental parameter" approach using the GUPIXWIN code. The main interest has been to test the possibility of false Fe detection in the presence of large Mn and Co peaks (sets A-B) and/or Mn in the presence of large Cr and Fe peaks (sets C-D). The results of the analyses indicate false hits of Fe (sets A-B), and larger reported Mn concentrations than expected (sets C-D). However, in all the cases the reported concentrations for Fe or Mn are in between the limits of detection and quantitation. The influence of surface roughness and other effects have been discussed.

X-ray fluorescence determination of the manganese valence state and speciation in manganese ores

“…For the samples with low iron, it is preferably to employ the ratio of MnKβ 5 /MnKβ 1,3 intensities because it gives the least error. For evaluating the presence of carbonate manganese, it is recommended to use MnKβ 5 /MnKβ 1,3 ratio, while for evaluating the presence of oxide manganese, it is recommended to use the MnKβ″/MnKβ 1,3 and MnKβ x /MnKβ 1,3 ratios. The XRF method does not require a complicated process for sample preparation and allows to receive fast information on the manganese valence state and speciation to assess the quality of manganese ore.…”

“…In some cases, the data on the valence state of transitional metals are important for specifying results of elemental analysis. [3] The techniques of titrimetric and potentiometric determination of manganese valence states are labor-consuming and scarce. [4] To determine manganese valence state in minerals, the following X-ray methods are applied: e.g.…”

“…The data on the manganese valence state (data) are used in geochemistry for evaluating the thermodynamic or physico‐chemical regime of the endogenous processes proceeding in the earth crust and upper mantle, as well as the exogenous processes. In some cases, the data on the valence state of transitional metals are important for specifying results of elemental analysis …”

Structure of the Ru, Ag and Te L X-ray emission spectra

“…1,2 Thus, an adequate set of experimental data for these parameters as well as a good description of satellite lines and radiative Auger emission (RAE) structures becomes crucial for a protable application of techniques such as electron probe microanalysis (EPMA), X-ray uorescence (XRF) or particleinduced X-ray emission (PIXE). 3,4 On the other hand, the X-rays emitted in atomic transitions contain useful information about the atomic structure, and several molecular and solid-state effects. A detailed study of the X-ray emission involving decays from inner-shell hole atomic states is therefore essential for a better understanding of the different processes that can take place as relaxation mechanisms.…”