Chemical Speciation of Arsenic-Accumulating Mineral in a Sedimentary Iron Deposit by Synchrotron Radiation Multiple X-ray Analytical Techniques

2008 ◽  
Vol 42 (19) ◽  
pp. 7152-7158 ◽  
Author(s):  
Satoshi Endo ◽  
Yasuko Terada ◽  
Yasuhiro Kato ◽  
Izumi Nakai
Author(s):  
Letizia Monico ◽  
Silvia Prati ◽  
Giorgia Sciutto ◽  
Emilio Catelli ◽  
Aldo Romani ◽  
...  

Redox processes activated by environmental factors have been identified as the main cause of the chromatic alterations of a number of artists’ pigments, including the yellow pigment orpiment (As2S3). Although...


2021 ◽  
Vol 17 ◽  
Author(s):  
Shuang Zhu ◽  
Yaling Wang ◽  
Chunying Chen

Background: The comprehensive understanding of nanomaterial behavior in biological systems is essential in accurately modeling and predicting nanomaterial fate and toxicity. Synchrotron radiation (SR) X-ray techniques, based on their ability to study electronic configuration, coordination geometry, or oxidative state of nanomaterials with high sensitivity and spatial resolution, have been introduced to analyze the transformation behavior of nanomaterials in biological systems. Methods: Previous research in this field are classified and summarized. Results: To start with, a brief introduction of a few widely used SR-based analytical techniques including X-ray absorption spectroscopy, X-ray fluorescence microprobe, scanning transmission X-ray microscopy and circular dichroism spectroscopy is provided. Then, the recent advances of their applications in the analysis of nanomaterial behaviors are elaborated based on different nanomaterial transformation forms such as biodistribution, biomolecule interaction, decomposition, redox reaction, and recrystallization/agglomeration. Finally, a few challenges faced in this field are proposed. Conclusion: This review summarizes the application of SR X-ray techniques in analyzing the fate of inorganic nanomaterials in biological systems. We hope it can help the readers to have a general understanding of the applications of SR-based techniques in studying nanomaterial biotransformation and to stimulate more insightful researches in relevant fields.


2009 ◽  
Vol 23 (04) ◽  
pp. 557-569 ◽  
Author(s):  
JAY ARRE TOQUE ◽  
ARI IDE-EKTESSABI

Synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) is a powerful technique for studying trace elements in biological samples and other materials in general. Its features including capability to perform measurements in air and water, noncontact and nondestructive assay are superior to other elemental analysis techniques. In this study, a technique for reconstructing elemental distribution mapping of trace elements from spectral data was developed. The reconstruction was made possible by using the measured fluorescent signals to obtain local differences in elemental concentrations. The proposed technique features interpolation and background subtraction using matrix transformations of the spectral data to produce an enhanced distribution images. It is achieved by employing polychromatic or monochromatic color assignments proportional to the fluorescence intensities for displaying single-element or multiple-element distributions respectively. Some typical applications (i.e., macrophage and tissue surrounding an implant) were presented and the samples were imaged using the proposed method. The distribution images of the trace elements of the selected samples were used in conjunction with other analytical techniques to draw relevant observations, which cannot be achieved using conventional techniques such as metallic uptake and corresponding cellular response. The elemental distribution images produced from this study were found to have better quality compared to images produced using other analytical techniques (e.g., SIMS, PIXE, XPS, etc).


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
G. Remond ◽  
R.H. Packwood ◽  
C. Gilles ◽  
S. Chryssoulis

Merits and limitations of layered and ion implanted specimens as possible reference materials to calibrate spatially resolved analytical techniques are discussed and illustrated for the case of gold analysis in minerals by means of x-ray spectrometry with the EPMA. To overcome the random heterogeneities of minerals, thin film deposition and ion implantation may offer an original approach to the manufacture of controlled concentration/ distribution reference materials for quantification of trace elements with the same matrix as the unknown.In order to evaluate the accuracy of data obtained by EPMA we have compared measured and calculated x-ray intensities for homogeneous and heterogeneous specimens. Au Lα and Au Mα x-ray intensities were recorded at various electron beam energies, and hence at various sampling depths, for gold coated and gold implanted specimens. X-ray intensity calculations are based on the use of analytical expressions for both the depth ionization Φ (ρz) and the depth concentration C (ρz) distributions respectively.


Author(s):  
B. Jouffrey ◽  
D. Dorignac ◽  
A. Bourret

Since the early works on GP zones and the model independently proposed by Preston and Guinier on the first steps of precipitation in supersaturated solid solution of aluminium containing a few percent of copper, many works have been performed to understand the structure of different stages in the sequence of precipitation.The scheme which is generally admitted can be drawn from a work by Phillips.In their original model Guinier and Preston analysed a GP zone as composed of a single (100) copperrich plane surrounded by aluminum atomic planes with a slightly shorter distance from the original plane than in the solid solution.From X-ray measurements it has also been shown that GP1 zones were not only copper monolayer zones. They could be up to a few atomic planes thick. Different models were proposed by Guinier, Gerold, Toman. Using synchrotron radiation, proposals have been recently made.


1987 ◽  
Vol 48 (C1) ◽  
pp. C1-175-C1-181
Author(s):  
S. AHMAD ◽  
M. OHTOMO ◽  
R. W. WHITWORTH

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-91-C9-94
Author(s):  
M. GRIONI ◽  
F. SCHAEFERS ◽  
J. B. GOEDKOOP ◽  
J. C. FUGGLE ◽  
J. L. WOOD ◽  
...  
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