Elemental composition chemistry

Auger electron spectroscopy (AES) is a technique used to identify the elemental composition, and in many cases, the chemical bonding of the atoms in the surface region of solid samples. It can be combined with ion-beam sputtering to remove material from the surface and to continue to monitor the composition and chemistry of the remaining surface as this surface moves into the sample. It uses an electron beam as a probe of the sample surface and its output is the energy distribution of the secondary electrons released by the probe beam from the sample, although only the Ai er electron component of the secondaries is used in the analysis. 

XPS is among the most frequently used techniques in catalysis. It yields information on the elemental composition, the oxidation state of the elements and, in favorable cases, on the dispersion of one phase over another [ J.W. Niemantsverdriet, Spectroscopy in Catalysis, An Introduction (2000), Wiley-VCH, Weinheim G. Ertl and J. Kiippers, Low Energy Electrons and Surface Chemistry (1985), VCH, Weinheim L.C. Feldman and J.W. Mayer, Fundamentals of Surface and Thin Film Analysis (1986), North-Holland, Amsterdam]. 

We have described new routes to useful preceramic organosilicon polymers and have demonstrated that their design is an exercise in functional group chemistry. Furthermore, we have shown that an organosilicon polymer which seemed quite unpromising as far as application is concerned could, through further chemistry, be incorporated into new polymers whose properties in terms of ceramic yield and elemental composition were quite acceptable for use as precursors for ceramic materials. It is obvious that the chemist can make a significant impact on this area of ceramics. However, it should be stressed that the useful applications of this chemistry can only be developed by close collaboration between the chemist and the ceramist. 

Varmuza, K., Liebmann, B., Friedl, A. University of Plovdiv Paisii Hilendarski —Bulgaria, Scientific Papers—Chemistry 35[5], 2007, 5-16. Evaluation of the heating value of biomass fuel from elemental composition and infrared data. 

In the remainder of this chapter, specific examples of fibrous minerals are presented. The chemical formulas are given as well as the mineral names. A formula is a shorthand notation that describes the elemental composition of the compound plus the specific ion associations, as determined by three-dimensional structure analysis of the species. Because every mineral sample is not completely analyzed, an ideal formula—one that summarizes the chemistry and associations of the ions—is usually presented. 

Hammerle RH, Pierson WR. 1974. Elemental composition of the aerosol in Pasadena, California. Prepared Papers of the American Chemical Society, Division of Environmental Chemistry, National Meeting, Los Angeles, CA, March 30-April 5, 1974, 14(l) 285-286. 

Elemental composition H 9.15%, N 42.41%, O 48.44%. Hydroxylamine may be measured by coulometric titration to a potentiometric end point using a coulometric titration cell. A standard solution of bromine may be used as oxidizer in the redox reaction. (Skoog, D. A., D. M. West, and F. J. HoUer. 1992. Fundamentals of Analytical Chemistry, 6th ed. pp. 467, Orlando Saunders College Publishing)... 

Tabulations of elemental compositions of C, H, N, and O for mass values up to 250 are listed in many texts on mass spectrometry. Consult these tables to see all possible alternatives. See also J. H. Bey non, Mass Spectrometry audits Applications to Organic Chemistry, Elsevier Publishing Co., Amsterdam, 1960. 

During the 1960s, high-resolution, double-focusing magnetic sector instruments became available from multiple manufacturers and were widely used in organic chemistry for exact mass measurements and elemental composition analysis. El was used for generating struc-... 

XPS will aid in understanding specifically the surface of the black deposit covering pictographs in Little Lost River Cave in Idaho. This work will complement other bulk analyses carried out with pyrolysis-GC-MS and thermally assisted hydrolysis /methylation (THM)-GC-MS (75). The objectives of this project were to use XPS to qualitatively determine the surface elemental composition of the black residue semiquantitatively characterize the surface, for comparison with other surface-related materials and examine the relationship between the chemistry and depth by using Ar+ sputtering. This, then, will aid in validating the radiocarbon date obtained through plasma-chemical oxidation and accelerator mass spectrometry by Steelman et al. (5). 

For chemical analysis, we used a mild acid-extraction procedure, based on recent experimental work (13, 26, 36, 37). We chose the extraction procedure over total digestion of the sample (35) because we are interested specifically in anthropogenic inputs by way of inorganic P and other elements, and not the total compositional chemistry (i.e., anthropogenic and diagenetic inputs). The extractant we used, composed of 20 ml of dilute 0.60 molar hydrochloric acid and 0.16 molar nitric acid, has been experimentally determined to remove soluble and readily labile P and other elements. While the extraction is not always proportional to the total P (or other elements) in soil, for activity area research we are concerned with the spatial patterns of elemental concentrations rather than absolute concentrations, as many variables affect elemental levels in soils (39, 40). 

Indian hemp [N.A. plant] fibers, charred and uncharred, 61-64/ Inductively coupled plasma-mass spectrometry (ICP-MS) and ICP-OES chemical analyses, Philistine potteiy, 402-411 correlation to LA-ICP-MS elemental analysis, Matisse bronze sculptures, 343-346 Olivella biplicata shell compositional chemistry, geographic patterning, 170-180 prehistoric textiles, 29,35 Roman Carthage curse tablets, 319, 332,333/... 

Typically, a broad energy (0-1000 eV) survey spectrum was acquired from each sample for elemental detection and then high resolution data for each element were collected to determine the surface chemistry and compositions of different samples. The elemental compositions of different samples were determined from the integrated area intensities of respective photoelectron peaks after normalizing for their relative sensitivity factors [20]. 

Standard analyses on whole heavy crude oil or residua, such as determinations of elemental compositions and various physical property tests (Chapter 2) have served to provide some indications of processability and may give an indication of the feedstock behavior. However, there is some question of the reliability of the tests when applied to the heavier feedstocks. For example, it might be wondered if the carbon residue tests (ASTM D-189, ASTM D-524, and ASTM D-4530) are really indicative of the yields of coke formed under process conditions. And, for the heavier feedstocks, it must be emphasized that to proceed from the raw evaluation data to full-scale production, insofar as the heavy feedstock is immediately used in the rehnery, is to proceed without caution. The thermal chemistry of the feedstock constituents will remain an unknown until the feedstock is used on-stream and the compatibility of the feedstock and the products with other feedstocks and products will also be unknown. Further evaluation of the processability of the feedstock is usually necessary. 

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