Determination of the copper oxidation state in a zeolite catalyst through the X-ray absorption edge/self-absorption effect by electron probe microanalysis

1994 ◽  
Vol 23 (6) ◽  
pp. 272-277
Author(s):  
Frank Cheng-Yu Wang
Keyword(s):  
Oxidation State ◽  
Absorption Edge ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Zeolite Catalyst ◽  
Copper Oxidation ◽  
Absorption Effect ◽  
X Ray ◽  
X Ray Absorption

X-Ray Absorption-Edge Determination of Cobalt in Complex Mixtures*

1961 ◽  
Vol 5 ◽  
pp. 379-388
Author(s):  
E.A. Hakkila ◽  
G.R. Waterbury
Keyword(s):  
Nitric Acid ◽  
Absorption Edge ◽  
Path Length ◽  
Construction Materials ◽  
X Ray ◽  
Relative Standard ◽  
Standard Deviations ◽  
Low X ◽  
X Ray Absorption

AbstractThe application of the X-ray absorption-edge technique was extended to the determination of cobalt in aqueous and alcoholic solutions containing a wide variety of impurity elements. In the procedure developed, secondary radiation from a 50% copper-nickel alloy is passed through an absorption cell filled alternately with the solvent and the sample solution. The transmitted Intensities of the Kα lines for copper and nickel are measured, and the concentration of cobalt is determined using accepted absorption principles. The K absorption edge for cobalt occurs at 1.604 A, restricting cell construction materials and solvents to those containing light elements with low X-ray absorption characteristics and also limiting the path length of the cell.Cells of 0.16- and 0.34-cm path length were used in the analysis of aqueous and alcoholic solutions, respectively. With the 0.16-cm path-length cell, relative standard deviations of 4.6 to 0.5% were obtained for cobalt concentrations ranging from 1.00 to 10.00 mg/ml for known aqueous solutions that contain various known concentrations of nitric acid. With the longer path-length cell, relative standard deviations from 1.8 to 0.46% were obtained for cobalt concentrations in the same range in known alcoholic solutions containing various known concentrations of nitric acid. The standard deviation of determining the blank is 0.043 mg of cobalt per milliliter for the 0.16-cm cell and 0.016 mg of cobalt per milliliter for the longer cell.A Norelco X-ray spectrograph with a three-position head was used in these analyses. Less than 5 min is required to convert this instrument from normal fluorescence operation to absorption-edge analysis. Approximately 15 to 20 analyses can be performed daily.

Direct determination of oxidation state of gold deposits in metal-reducing bacterium Shewanella algae using X-ray absorption near-edge structure spectroscopy (XANES)

2007 ◽  
Vol 103 (6) ◽  
pp. 568-571 ◽  
Author(s):  
Yasuhiro Konishi ◽  
Takeshi Tsukiyama ◽  
Norizoh Saitoh ◽  
Toshiyuki Nomura ◽  
Shinsuke Nagamine ◽  
...  
Keyword(s):  
Oxidation State ◽  
Direct Determination ◽  
Gold Deposits ◽  
Edge Structure ◽  
X Ray ◽  
Shewanella Algae ◽  
X Ray Absorption

scholarly journals Signatures of technetium oxidation states: a new approach

2020 ◽  
Vol 56 (67) ◽  
pp. 9608-9611
Author(s):  
Stephen Bauters ◽  
Andreas C. Scheinost ◽  
Katja Schmeide ◽  
Stephan Weiss ◽  
Kathy Dardenne ◽  
...  
Keyword(s):  
Oxidation State ◽  
Oxidation States ◽  
General Strategy ◽  
New Approach ◽  
X Ray ◽  
X Ray Absorption

A general strategy for the determination of Tc oxidation state by a new approach involving X-ray absorption near edge spectroscopy (XANES) at the Tc L3 edge is shown.

A new and versatile computer program for correcting EPMA data

1992 ◽  
Vol 50 (2) ◽  
pp. 1658-1659
Author(s):  
I Farthing ◽  
G Love ◽  
VD Scott ◽  
CT Walker
Keyword(s):  
Chemical Composition ◽  
Computer Program ◽  
Programming Language ◽  
Atomic Number ◽  
Processing Speed ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Epma Data ◽  
X Ray ◽  
X Ray Absorption

A new computer program has been developed to convert electron probe microanalysis data into accurate measurements of chemical composition. It is menu-based and designed to operate off-line using any IBM PC compatible computer. As shown in the flowchart, fig. 1, the architecture is modular and the programming language adopted is a compilable version of BASIC which possesses much of the processing speed associated with FORTRAN or C. Specimens containing up to fifteen elements, with 4 ≤ Z ≤ 96, can be handled and all the major x-ray lines (Kα, Kβ, Lα, L(β, Mα and Mβ) are available for analysis purposes.The procedure itself is based upon the classical ZAF approach in which corrections for atomic number (Z), x-ray absorption (A), characteristic fluorescence (Fl) and continuum fluorescence (F2) are treated independently. The factors dealing with fluorescence are essentially those of Reed (characteristic) and Springer (continuum) although both contain minor updates. However, the atomic number and absorption factors are the authors' own and the latter, developed from a quadrilateral representation of the x-ray distribution with depth in a solid, distinguishes this program from others.

Absorption Correction Curves Obtained from Measurements of the Production of X-Rays as a Function of Depth

1972 ◽  
Vol 16 ◽  
pp. 198-205
Author(s):  
J.D. Brown ◽  
L. Parobek
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
X Rays ◽  
Matrix Elements ◽  
X Ray ◽  
Absorption Correction ◽  
Correction Equations

AbstractMeasurements of x-ray production as a function of depth in a sample (ϕ(ρz) curves) are fundamental to the determination of the quantitative equations for relating x-ray intensity to composition in electron probe microanalysis. These ϕ(ρz) curves have been measured for four different voltages and a number of different tracers in aluminum, copper, silver arid gold as matrix elements. From these ϕ(ρz) curves the absorption correction curves (f(x) curves) can be calculated. Such curves have been obtained and comparison is made with the absorption correction equations of Philibert. The effect of a tilted sample on the absorption correction is also discussed.

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