X-ray absorption spectroscopy , for

X-ray Absorption Spectroscopy for Characterizing Metal Clusters in Proteins... 

Hayes, K. F. Katz, L. E. 1996. Application of X-ray absorption spectroscopy for surface complexation modelling of metal ion sorption. In Brady, P. V. (ed) Physics and Chemistry of Mineral Surfaces. CRC Press, Boca Raton, 147-223. 

The utility of sulfur K-edge X-ray absorption spectroscopy for the determination and quantification of sulfur forms in nonvolatile hydrocarbons has been investigated. X-ray Absorption Near Edge Structure (XANES) spectra were obtained for a selected group of model compounds, for several petroleum asphaltene samples and for Rasa coal. For the model compounds the sulfur XANES was found to vary widely from compound to compound, and to provide a fingerprint for the form of sulfur involved. The use of third derivatives of the spectra enabled discrimination of mixtures of sulfide and thiophenic model compounds, and allowed approximate quantification of the amount of each component in the mixtures, in the asphaltene samples and the coal. These results represent the first demonstration that nonvolatile sulfide and thiophenic sulfur forms can be distinguished and approximately quantified by direct measurement. 

J. E. Penner-Hahn, X-ray Absorption-Spectroscopy for Characterizing Metal-Clusters in Proteins—Possibilities and Limitations , ACS Symposiinn Series, L. Que, Jr (Ed), 1988, Vol. 272, p. 24. 

XANES (X-ray Absorption Near-Edge Strueture) is X-ray absorption spectroscopy for the lower energy region than EXAFS (Extended X-ray Absorption Fine Structure). It is sensitive to the local atomic arrangement around the absorbing atom and to the chemical states because the low energy electrons emitted through the photoabsorption are affected by details of the molecular potential (1). 

The detection system depends mostly on the concentration of absorbing atoms in the material. For bulk x-ray absorption spectroscopy for concentration above 10 atomic ratio standard x-ray transmission techniques are used. Incident and transmitted flux are measured by photoionization chambers. 

Scott, R. A., and M. K. Eidsness. The use of x-ray absorption spectroscopy for detection of metal-metal interactions Application to copper-containing enzymes. Comments Inorg. Chem. 7 (1988), 235-267. 

Foster AL, Brown GE, Tingle TN, Parks GA (1997) Quantitative arsenic speciation in mine tailings using X-ray absorption spectroscopy. Am Mineral 83 553-568 Gaillard JF, Webb SM, Quintana JPG (2001) Quick X-ray absorption spectroscopy for determining metal speciation in environmental samples. J Synch Rad 8 928-930 Gerward L (1981) Analytical approximations for X-ray attenuation coefficients. Nucl Instr Meth Phys Res 181 11-14... 

Adjunct Professor of Physics at Utah State University. After completing her M. A. in Physics and PhD. in Biophysics at Harvard University, she became a member of the technical staff at AT T Bell Laboratories. She joined the USU faculty in 1988. She has a broad scope of expertise from biochemistry to electrical engineering, and has considerable experience in heme protein catalysis, structural biology, and the design and construction of optical and X-ray instrumentation. She was a pioneer the use of X-ray absorption spectroscopy for the investigation of biological problems and has authored more than 100 technical publications in refereed journals and books. 

Different characterization techniques are used to get an insight into the location of transition metal ions in an aluminophosphate framework. Generally, the data on the cation location are collected with difficulty since the metal concentration is low. In this regard, it is necessary to use more than one method if a reliable conclusion is to be reached (ie, the simultaneous application of several physical techniques is recommended). The following characterization methods are commonly applied diffuse reflectance UV-vis spectroscopy (DRS), electron spin resonance (ESR), electron spin echo modulation (ESEM), infrared (IR), and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopies, as well as the nuclear magnetic resonance spectroscopy (NMR), Mossbauer spectroscopy and the X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption spectroscopy for fine structure (EXAFS) (167,168) and references therein). 

APPLICATIONS OF SOFT X-RAY ABSORPTION SPECTROSCOPY FOR IN SITU STUDIES OF CATALYSTS AT NANOSCALE... 

Grunwaldt J-D, Liitzenkirchen-Hecht D, Richwin M, Grundmann S, Clausen BS, Frahm R (2001) Piezo X-ray absorption spectroscopy for the investigation of solid-state transformations in the millisecond range. J Phys Chem B 105 5161-5168. doi 10.1021/ jp010092u... 

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