scholarly journals A Mineralogical, Geochemical, and Geochronological Study of ‘Valencianite’ from La Valenciana Mine, Guanajuato, Mexico

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 741
Author(s):  
Jesús Solé ◽  
Teresa Pi-Puig ◽  
Amabel Ortega-Rivera
Keyword(s):  
Rietveld Refinement ◽  
Morphological Changes ◽  
Trace Element Analysis ◽  
Ore Deposits ◽  
New Mineral ◽  
Triangular Diagram ◽  
Element Analysis ◽  
X Ray ◽  
Three Samples ◽  
Geochronological Study

Valencianite has been described as a variety of K-feldspar (adularia) from La Valenciana mine, Guanajuato, Mexico, from which three samples were used for this study. We present new major and trace element analysis, X-ray powder diffraction with Rietveld refinement, and single-crystal 40Ar/39Ar ages of this classical mineral. A detailed review of major works on feldspars and relevant papers from adularia shows that the structure of this mineral has monoclinic and triclinic domains with variable degrees of Al/Si order that we have been only able to model by powder X-ray diffraction assuming the presence of monoclinic (~50%) plus triclinic (~50%) K-feldspar. The literature data show some extreme structural states for adularia obtained in the pre-Rietveld refinement era; these data are dubious and need to be reanalyzed. A triangular diagram using the relative development of {110}, {010} and {001} faces is proposed. The temperature of formation, the Na/K ratio, and the growth kinetics seem to be the main factors controlling the morphological changes in K-feldspar crystals. The geochemistry of valencianite shows an almost pure orthoclase composition, as is common in most adularia crystals, although compositions up to Or90Ab10 have been found. Measurement of thallium in adularia can be an exploration guide for ore deposits. The weighted mean of 15 40Ar/39Ar analyses of one valencianite from La Valenciana mine gave an age of 30.43 ± 0.27 Ma (2 standard deviations). It is discussed whether valencianite can be considered a new mineral.

An improved interference correction for trace element analysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1646-1647
Author(s):  
John J. Donovan ◽  
Donald A. Snyder ◽  
Mark L. Rivers
Keyword(s):  
Trace Element Analysis ◽  
Accurate Estimate ◽  
Simple Expression ◽  
Standard Reference Materials ◽  
Characteristic Line ◽  
Analytical Line ◽  
Element Analysis ◽  
Electron Probe Analysis ◽  
Calculated Concentration ◽  
X Ray

We present a simple expression for the quantitative treatment of interference corrections in x-ray analysis. WDS electron probe analysis of standard reference materials illustrate the success of the technique.For the analytical line of wavelength λ of any element A which lies near or on any characteristic line of another element B, the observed x-ray counts at We use to denote x-ray counts excited by element i in matrix j (u=unknown; s=analytical standard; ŝ=interference standard) at the wavelength of the analytical line of A, λA (Fig. 1). Quantitative analysis of A requires an accurate estimate of These counts can be estimated from the ZAF calculated concentration of B in the unknown C,Bu measured counts at λA in an interference standard of known concentration of B (and containing no A), and ZAF correction parameters for the matrices of both the unknown and the interference standard at It can be shown that:

Improvement of the Detection Sensitivity of Edxrf Trace Element Analysis by Means of Efficient X-Ray Focusing Based on Strongly Curved Hopg Crystals

1995 ◽  
Vol 39 ◽  
pp. 109-117
Author(s):  
Burkhard Beckhoff ◽  
Birgit Kanngießer
Keyword(s):  
High Intensity ◽  
Focal Plane ◽  
Bragg Reflection ◽  
Pyrolytic Graphite ◽  
Trace Element Analysis ◽  
Detection Sensitivity ◽  
Element Analysis ◽  
X Ray ◽  
Wide Range ◽  
Very High

X-ray focusing based on Bragg reflection at curved crystals allows collection of a large solid angle of incident radiation, monochromatization of this radiation, and condensation of the beam reflected at the crystal into a small spatial cross-section in a pre-selected focal plane. Thus, for the Bragg reflected radiation, one can achieve higher intensities than for the radiation passing directly to the same small area in the focal plane. In that case one can profit considerably from X-ray focusing in an EDXRF arrangement. The 00 2 reflection at Highly Oriented Pyrolytic Graphite (HOPG) crystals offers a very high intensity of the Bragg reflected beam for a wide range of photon energies. Furthermore, curvature radii smaller than 10 mm can be achieved for HOPG crystals ensuring efficient X-ray focusing in EDXRF applications. For the trace analysis of very small amounts of specimen material deposited on small areas of thin-filter backings, HOPG based X-ray focusing may be used to achieve a very high intensity of monochromatic excitation radiation.

Trace element analysis via heavy ion induced X-ray fluorescence

1976 ◽  
Vol 279 (2) ◽  
pp. 160-160 ◽  
Author(s):  
R. Zeisler ◽  
J. Cross ◽  
E. A. Schweikert
Keyword(s):  
Trace Element ◽  
Trace Element Analysis ◽  
Heavy Ion ◽  
Element Analysis ◽  
X Ray

Optimization of PIXE quantitative system to assist traceability of pearls

2017 ◽  
Vol 27 (03n04) ◽  
pp. 125-133
Author(s):  
S. Murao ◽  
K. Sera ◽  
S. Goto ◽  
C. Takahashi ◽  
L. Cartier ◽  
...  
Keyword(s):  
Supply Chain ◽  
Trace Element ◽  
Standard Method ◽  
Good Accuracy ◽  
Trace Element Analysis ◽  
Social Attention ◽  
Element Analysis ◽  
X Ray ◽  
Cultured Pearls

Recent rise of social attention towards ethical jewelry has led scientists to a challenge of how to construct analytical systems that can deliver in line with social and supply chain expectations. Of the various kinds of methods, “Proton/Particle-Induced X-ray Emission” (PIXE) seems to be robust and promising in characterizing gemstones because of its capability of trace element analysis without destruction. The authors established a non-standard method to analyze cultured pearls and applied it to test specimens from different places. The results showed that PIXE could detect important elements for pearl study with good accuracy and sensitivity and that pearl chemistry can be useful to differentiate freshwater and marine pearl products.

X-ray Total Reflection Fluorescence Analysis of Iron, Copper, Zinc, and Bromine in Human Serum

1988 ◽  
Vol 42 (7) ◽  
pp. 1250-1253 ◽  
Author(s):  
C. T. Yap
Keyword(s):  
Trace Element Analysis ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
Element Analysis ◽  
X Ray ◽  
Iron Copper ◽  
Control Serum ◽  
Human Sera ◽  
Copper Zinc ◽  
Good Agreement

The method of total reflection fluorescence analysis was used to obtain concentrations of iron, copper, zinc, and bromine in human sera. It was first applied to the commercial control-serum preparation known as Seronorm, and the results obtained were in good agreement with quoted values. The method was then used to determine the concentrations of iron, copper, zinc, and bromine in a random sampling of 62 individuals in an essentially Chinese population. The results are discussed. We feel that this is a suitable method for trace-element analysis of blood in an average laboratory. It is rapid, simple, and economical, besides being multielemental and nondestructive and requiring very small quantities—which seems to be a must in pediatrics.

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