A Raman, infrared and XRD analysis of the instability in volcanic opals from Mexico

A series of natural volcanic opal samples with the destabilization phenomena from Mexican deposits (states of Queretaro and Jalisco) was investigated by Raman microprobe (RMP), infrared spectrometry and XRD analysis. These techniques show that at low and room temperatures the unaltered transparent opals may be transformed into destabilized white opals, which are a mixture of different polymorphs of tridymite and alpha-cristobalite with various degrees of crystallinity. We found systematic changes in frequencies of both the Raman and the infrared bands, caused by increasing regularities of bond-lengths and bond-angles Si-O-Si groups under the effect of stability. Micro-Raman spectrometry confirms that in the destabilized opal the principal mineral phases are MC (monoclinic ordered)- and MX (incommensurate monoclinic)-tridymites that are characterized by more structural order in comparison with other structural modification of this phase in unaltered opal (POn pseudo-orthorhombic disordered tridymite). XRD investigations show that in the sequence from unaltered to destabilized opal the position of principal maximum (4.30, 4.10 and 2.50 A) shifts towards higher d-spacing. This XRD shifting to higher d-spacing can largely be explained by an increasing amount of tridymite stacking and unresolved superposition of cristobalite and tridymite reflections. The destabilization phenomena in volcanic opals is due to the structural ordering/disordering that is characterized mainly by the formation of the different tridymite polymorphs (MC and MX) in the destabilized opal-CT as well as the decreasing content of molecular water in the structure.     

Reaction of Elemental (White) Phosphorus with (Alkoxymethyl)dialkylamines

The reaction of elemental (white) phosphorus with (alkoxymethyl)dialkylamines in the presence of sodium alkoxide results in complete conversion of P₄ in proton-donor solvents only. ³¹P NMR spectroscopy allowed detection of the initial formation of PIII compounds whose subsequent transformations primarily provide phosphinate and phosphonate structures. Under the reaction conditions, trialkyl phosphites further react with (alkoxymethyl)dialkylamines to form dialkyl (dialkylamino)methylphosphonates.     

Elemental analysis of alloys by XRF

XRF was used for routine analysis of different kinds of alloys, such as archeological findings, materials used in dentistry, and Al alloyed with Ga used in industry. The results of these analyses are described in this paper.     

三角帆蚌黄白黑珍珠元素分析及药用价值评价

珍珠具有定惊安神、明目去翳、解毒生肌、清热堕痰等功效。此外,淡水珍珠还作为一种天然材料应用于化妆品工业[1]。对不同颜色的淡水珍珠的常量及微量元素含量分析,对于探讨珍珠的药用价值及不同色彩形成的机理具有重要意义。1　材料与方法三种不同颜色的珍珠采集于湖北省松滋市小南海,淡水人工养殖的三角帆蚌体内,经蒸馏水清洗后,40°C～45°C鼓风烘干。spectrAAZ(220)原子吸收光谱仪;spectrAAFS(220)原子吸收光谱仪;ICAP9000-2000型等离子体直读光谱仪;马弗炉等。准确称取黄、白、黑三种不同颜色珍珠5g,捣碎后置于马弗炉内550°…     

Polarographic analysis of the reduction waves of Pt(II)-SATSC complex

A polarographic study of the Pt(II)-salicylaldehyde thiosemicarbazone complex in sodium perchlorate as supporting electrolyte is described. In addition to the reduction wave of the complex, a catalytic hydrogen wave is also recorded. The characteristics of this catalytic hydrogen wave are studied under different experimental conditions such as varying acid/complex/supporting electrolyte/surfactant concentrations and also with mercury droptime. Based on these, a probable mechanism for the electrode process has been postulated. Presented at the 12th Annual Symposium in Chemistry held at the Indian Institute of Technology, Madras in March 1987.     

Elemental analysis of limestone by instrumental neutron activation analysis

Limestone samples from Assuit Governrate in Upper Egypt were subjected to elemental analysis by instrumental neutron activation analysis and X-ray fluorescence techniques. The samples were properly prepared together with their standards and simultaneously irradiated in a neutron flux of the order 7 × 1011 n/cm² s using TRIGA research reactor at Mainz. After activation the samples were subjected to γ-ray spectrometry using a high purity germanium detection system and computerized multichannel analyzer. Nineteen elements: Na, Ca, Mn, Fe, Sc, Cr, Co, Zn, Sn, La, Ce, Nd, Eu, Sm, Yb, Lu, Hf, Th and U were analyzed. X-ray fluorescence spectrometry have been also used. The presence of any elements in higher or lower levels in certain limestone samples is contingent on the occurrence of its bearing minerals, nature of parent sediments and depositional environments of these sediments. The major elements in the samples were also observed to be among the elements that had high enrichment factors in the study of suspended dust particulate within and around cement industries. This confirms cement as the major contributor to the airborne particulate matter in the environs.     

Elemental fluorine in organic chemistry (1997-2006)

The use of elemental fluorine as a reagent over the period 1997-2006 for carbon-fluorine bond formation in organic synthesis is reviewed. Recent advances in the exhaustive fluorination of ethers and esters to give perfluorinated systems, selective direct fluorination of aliphatic, aromatic, heterocyclic and carbonyl systems and the application of microreactor techniques to direct fluorination are discussed.     

Linear-dichroic infrared spectral analysis of Cu(I)-homocysteine complex

The interaction between homocysteine (HCysSH) and Cu(II) leads to the formation of a yellow complex [Cu(I)(HCysS-SCysH)2]Cl (1) after redox processes in the Cu(II)-homocysteine system resulting in dimerization of the ligand and formation of a mononuclear Cu(I) complex with two dimers. The structure of (1) was obtained by IR-LD spectral analysis of a solid amorphous sample oriented in nematic liquid crystal medium. The original technique for orientation developed here and the polarized IR spectra thus obtained, permit the determination of the complexation sites and coordination mode of diamagnetic complexes. In the complex (1), Cu(I) is coordinated through the two O atoms of one COO- group of each of the ligands and the metal ion coordination sphere represents a distorted tetrahedron.     

Elemental analysis of human placenta by neutron irradiation and gamma-ray spectrometry (standard,prompt and fast-neutron)

Human placental tissue from 100 hospitalized deliveries were analysed for Ag, Al, As, Au, B, Ba, Br, Ca, Cd, Cl, Co, Cr, Cs, Cu, F, Fe, I, Hg, K, La, Mg, Mn, Mo, Na, Ni, Rb, S, Sb, Sc, Se, Sn, Sr, Ti, V, W and Zn using a combination of pre-chemical separation of sodium with hydrated antimony pentoxide and instrumental neutron activation analysis. Boron and Si values were determined using prompt gamma-ray and fast-neutron techniques respectively. Analysis of NBS-SRM Bovine Liver 1577 and a pooled standard placental tissue for 33 elements showed a good agreement with most coefficients of variation less than or equal to 15%, and recoveries of 91–104%. Symmetrical distributions, were obtained for all elemental placental values. Only Cd(–) and Zn(+) showed statistically significant correlations with birth weight, gestational age and placental weight. The influence of cigarette smoking is considered a major factor in producing elevated cadmium levels in the placental tissue of smokers and passive smokers, and hence lower birth weights.     

Elemental content of erythrocytes from patients undergoing Coronary Artery Bypass Grafting (CABG) surgery using PIXE analysis

Summary This on-going study was conducted on erythrocytes to further establish the content of elements of blood fractions from patients undergoing Coronary Artery Bypass Grafting (CABG) surgery. As the quality and quantity of elements in these samples were unknown, proton induced X-ray emission (PIXE) analysis was chosen for its multi-elemental analysis capabilities on small mass samples. Previous work demonstrated the detection of several elements using PIXE analysis and that the elemental concentrations of S, Cl, Ca and Fe were worthy of note. It is indicated that continuing analysis of these cell fractions may be significant in the study of trace element metabolism as it provides insight into understanding mechanisms for preventative, diagnostic and therapeutic purposes and hence a patient's state of health. The analysis of erythrocytes was conducted at pre, during and post-operative timepoints to investigate the changes that occur during and post-surgical intervention. Elements Na, Mg, Si, P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb were detected in erythrocytes at all surgery timepoints and from normalized graphs, elements S, K and Fe revealed that the changes in concentration through surgery followed an almost identical pattern. It is anticipated that statistical correlation and interpretation of data may provide, in the long-term, information that could have an impact on the patients' rate of recovery or appropriate aftercare.     

Reactions of Tri(1-propenyl)amine with Elemental Sulfur

The reaction of tri(1-propenyl)amine with elemental sulfur in bipolar aprotic solvent (DMF'DMSO) at 50°C within 1.5 h furnished 5-methyl-2-ethylthiazole in 62% yield. 2H'5H-5-methyl-2-ethyl-thiazole, 2-hydroxy-5-methylbenzaldehyde were found among the side products. The formation paths of thecompounds obtained are suggested.     

Elemental depth profile analysis of hard coatings of tungsten carbide by auger electron (AES-) microprobe/sputtering

Summary Technological wear-resistant hard coatings prepared by chemical vapour deposition (CVD) of 8 to 15 m tungsten carbide on steel, were studied by Auger electron spectrometry (AES)/sputtering. Special regard was given to the problem of the analysis of the carbide signal, which is interfered in surface thin-film analysis, in general, by adventitious, ubiquitous carbon overlayers. Semiquantitative AES in-depth profiles of W, C, Fe, Cr, O reproducibly showed characteristic differences between samples from different coating processings and those with good and bad coating/base adhesion, respectively. Although strong sputter-induced roughening occurred, quite acceptable depth resolution of the order of initial sample roughness of 0.5 to 1 m was obtained by means of the Auger microprobe even after sputter removal of thick layers > 10 m.Standard thin-film materials, well-characterized by a combined approach using different complementary thinfilm analytical methods, are discussed as a means to improve accuracy of quantitative in-depth analysis of such rough technological coatings.

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Element-Tiefenprofilanalyse von Hartstoffschichten aus Wolframcarbid durch Auger-Elektronen-(AES-)Mikrosonde/Ionenzerstäuben

Zusammenfassung Technische CVD-Hartstoffbeschichtungen zum Verschleißschutz aus 8 bis 15 m dicken Wolframcarbidschichten auf Stahl wurden mit Auger-Elektronen-Spektrometrie (AES)/Ionenätzen untersucht. Dem Problem der Analyse des Carbid-Signals, das allgemein in der Dünnschichtanalyse durch zufällige, allgegenwärtige Kohlenstoffbelegungen gestört wird, wurde besondere Aufmerksamkeit gewidmet. Halbquantitative AES-Tiefenprofile von W, C, Fe, Cr, O zeigten reproduzierbar charakteristische Unterschiede zwischen Proben, die unter verschiedenen Beschichtungsbedingungen hergestellt worden waren, sowie solchen mit guter bzw. schlechter Haftung auf dem Grundmaterial. Durch den Einsatz der Auger-Mikrosonde wurden trotz starker Probenaufrauhung auch nach Abtrag dicker Schichten > 10 m durch Ionenzerstäuben gute Tiefenauflösungen von 0,5 bis 1 m in der Größe der ursprünglichen Probenrauheit erhalten.Der Einsatz von Standard-Dünnschichtmaterialien, die zuvor durch eine Kombination verschiedener dünnschichtanalytischer Methoden umfassend charakterisiert wurden, wird als eine Möglichkeit diskutiert, die Richtigkeit der quantitativen Dünnschichtanalyse derartiger technischer Beschichtungen zu verbessern.

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Dedicated to Prof. Dr. Karl-Heinz König on the occasion of his 60th birthday     

Comparison of background gamma-ray spectra between Los Alamos, New Mexico and Austin, Texas

Background counts in gamma-ray spectrometry are caused by a variety of sources. Among these are naturally occurring radioactive materials (NORM) in the environment, interactions from cosmic radiation, and contamination within the laboratory. High-purity germanium detectors were used to acquire long background spectra in Los Alamos, NM (elevation ~7,300 feet) and Austin, TX (elevation ~500 feet). This difference in elevation has a sizeable effect on background spectra due to cosmic interactions, such as (n,n′) and (n,γ). Los Alamos also has a fairly high NORM concentration in the soil relative to Austin, and this gives way to various spectral interferences. When analyzing nuclear forensics samples, these background sources can have non-trivial effects on detection limits of low-level fission products. By accurately determining the influence that elevation and environment have on background spectra, interferences within various laboratory environments can be more accurately characterized.     

The use of copper(III) complex compounds for the thermochemical analysis (DIE) of different organic substances

Potassium diperiodatocuprate(III), K₇[Cu(IO₆)₂], was tested as a reagent for the determination of mono- and disaccharides by means of direct injection enthalpimetry. The reagent reacted readily with acyclic polyhydroxy compounds, the reaction proceeding the better, the more hydroxy groups there were in the substance and the closer the hydroxy groups were one to the other. It also reacted readily with phenols, the polyhydric ones in particular. Carbonyl and amino compounds mostly didn't react or did so slowly, but reacted readily in the presence of some other reactive group such as hydroxy, sulphhydryl or thioxo group. Semicarbazide reacted readily, presumably due to the presence of the reactive-CO-NH-group. It is concluded that carboxy groups in the proximity of hydroxy groups exercise a positive effect on the reaction. The presence of a nitro or sulphonic acid group has a negative effect on the course of the reaction with the copper(III) compound.

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Zusammenfassung Kalium-diperiodatocuprat(III), K₇[Cu(JO₆)₂], wird als Reagenz für die Bestimmung von Mono- und Disacchariden durch direkte Injektionsenthalpimetrie vorgeschlagen. Es wurde festgestellt, daß das Reagenz leicht mit azyklischen Polyhydroxy-Verbindungen reagiert, und zwar umso besser, je mehr Hydroxylgruppen die Substanz enthält und je näher diese beieinander liegen. Das Reagenz reagiert leicht mit Phenolen, insbesondere wenn diese mehrere Hydroxylgruppen enthalten. Carbonyl- und Aminoverbindungen reagieren meistens nicht oder nur langsam, aber leicht in Gegenwart einiger anderer reaktiver Gruppen, wie Hydroxy-, Sulfhydryl- oder Thioxogruppen. Semicarbazid reagiert leicht, wahrscheinlich wegen der reaktiven Gruppe-CO-NH₂-. Es wird der Schluß gezogen, daß Carboxylgruppen in der Nachbarschaft von Hydroxylgruppen eine positive Wirkung auf die Reaktion ausüben. Die Anwesenheit der Nitro- oder Sulfonsäuregruppe wirkt sich negativ auf den Verlauf der Reaktion mit Kupfer(III)-Verbindungen aus.

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- K₇[u(IO₆)₂] — - . , . , . , , . . , -, - , . , , , -NH-. , , , , - .

     

Elemental Sulfur as Monomer in Syntheses of Poly (Arylene Sulfides)

Abstract

Direct polycondensation of elemental sulfur with benzene, naphthalene. binuclear aromatic hydrocarbons as well as substituted benzenes and their mixtures has been investigated. The mechanism of polycondensation, structure and propeties of poly(arylene sulfides) formed has been studied.     

Elemental analysis of fertilizer by fast neutron activation

A simple and accurate technique has been developed to analyse the commercial fertilizers for phosphorous, potassium, chlorine, magnesium and silicon. The method is based on the fast neutron activation.     

Reaction of Elemental Phosphorus (P4) with Thiophenol in the Presence of Amines

Elemantal phosphorus (P₄) reacts with thiophenol and amines at elevated temperature in acetonitrile to give ammonium or acetimidamidium S,S-diphenyl phosphorodithioates, depending on the nature of the amine. Analogous salts were isolated in the reaction of triphenyl phosphorotrithioite with thiophenol and corresponding amines in acetonitrile. The molecular and crystal structures of the acetimidamidium salt was confirmed by X-ray diffraction. With two different types of intermolecular interactions taken into account, a 1D supramolecular structure formed by infinite cylinders, rather that 0D structures, dimers of anion-cation pairs formed by classical hydrogen bonds exclusively, was obtained. S,S,S-Triphenyl phosphorotrithioate is formed by the reactions of P₄ with thiophenol and a catalytic amount of an amine or in the presence of diphenyl disulfide.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 886–892.Original Russian Text Copyright © 2005 by Badeeva, Batyeva, Gubaidullin, Litvinov, Sinyashin.     

Elemental analysis of high-purity solids by mass spectrometry

The applications of mass spectrometry in the determination of trace elements in some of the high-purity solid materials used in modern technology are reviewed.     

Evaluation of isotope-coded protein labeling (ICPL) in the quantitative analysis of complex proteomes

An evaluation of the ICPL (isotope-coded protein labeling) non-isobaric labeling technique was performed using two different biological models. Two samples containing phage T4 capsids were mixed in a 1:1 ratio after being labeled with the light or heavy versions of the ICPL reagent. The analysis of this proteome demonstrated the feasibility of this approach for differential quantitative proteomics and was employed to optimize the experimental parameters of the ICPL workflow. ICPL-mediated analysis of two more complex proteomes, those of a Salmonella enterica serovar Typhimurium virulent strain and an isogenic attenuated mutant, and its comparison with the results obtained in a 2D-PAGE “classical” approach confirmed that ICPL is a valuable alternative to other labeling techniques currently in use. In addition, our results suggest that labeling at the peptide level instead of following the standard ICPL workflow should increase both the number of proteins quantified and the reliability of the quantification.