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The review is devoted to the capabilities of gas chromatography-mass spectrometry in the analysis of high-purity volatile hydrides of naturally occurring and isotopically enriched compositions. Problems related to experimental techniques, chromatographic separation, identification, and quantitative determination of impurities are discussed. The application of this method has significantly expanded data coverage on the nature, number, and limiting possibilities of the determination of impurities in volatile inorganic hydrides. The identified impurities are compounds of various classes. Among them are atmospheric gases; saturated, unsaturated, and aromatic C.sub.1-C.sub.9 hydrocarbons; chlorine- and fluorine-containing C.sub.1-C.sub.4 hydrocarbons; homologues and alkyl derivatives of hydrides; Si.sub.2-Si.sub.4 siloxanes; fluorosiloxanes; oxygen-containing hydrocarbons; sulfur-containing substances; and hydrides of other elements. Gas chromatography-mass spectrometry analysis made it possible to detect the presence of impurities in isotopically enriched silicon and germanium hydrides, which are their molecular isobars. The use of gas chromatography-mass spectrometry in the analysis of high-purity inorganic hydrides makes it possible to reach the detection limits of impurities of 10.sup.-8-10.sup.-5 mol %., Author(s): A. Yu. Sozin [sup.1], V. A. Krylov [sup.2], O. Yu. Chernova [sup.1], T. G. Sorochkina [sup.1], A. P. Kotkov [sup.3], N. D. Grishnova [sup.3], A. I. Skosyrev [sup.3], G. [...]

The impurity composition of arsine is studied by gas chromatography-mass-spectrometry. Impu-rities of permanent gases; carbon dioxide; hydrides; saturated, unsaturated, and aromatic hydrocarbons C.sub.1-C.sub.6; halogenated hydrocarbons; sulfur compounds; and arsine and diarsine alkyl derivatives are determined. The impurity level of high-purity arsine is 10.sup.-6-10.sup.-5 vol %. Impurity concentrations in arsine after synthesis and in the fractions extracted in the course of its rectification are rather high and lie in the range 10.sup.-6-0.1 vol %. The limits of detection for impurities are 2 x 10.sup.-7-2 x 10.sup.-4 vol %., Author(s): A. Yu. Sozin [sup.1], T. G. Sorochkina [sup.1], O. Yu. Chernova [sup.1], A. P. Kotkov [sup.2], N. D. Grishnova [sup.2], D. M. Polezhaev [sup.2], G. V. Pushkarev [sup.2], S. [...]

A method of chromatography-mass spectrometry is used to study the impurity composition of arsine synthesized by the reaction of arsenic chloride with sodium borohydride. Capillary adsorption columns with adsorbents modified silica and polytrimethylsilylpropine is used for the separation of impurities. Impurities are identified by comparing their mass spectra with the NIST database, published data, as well as by reconstructing their structures from fragment ions. Impurities of permanent gases; saturated and unsaturated hydrocarbons C.sub.1-C.sub.6; chlorinated, oxygenated, and aromatic hydrocarbons; volatile inorganic hydrides; and alkyl derivatives of arsine, trimethyl fluorosilane, carbon sulfur dioxide, and dimethyl sulfide are identified in arsine. Mass spectra of C.sub.2H.sub.3AsH.sub.2, CH.sub.3AsHC.sub.2H.sub.5, and C.sub.2H.sub.5As.sub.2H.sub.3 impurities are obtained for the first time., Author(s): A. Yu. Sozin [sup.1], O. Yu. Chernova [sup.1], T. G. Sorochkina [sup.1], A. P. Kotkov [sup.1] [sup.2], N. D. Grishnova [sup.1] [sup.2], D. M. Polezhaev [sup.2], G. V. Pushkarev [...]

The aim of this work was the development of an as-simple-as-possible instrument for trace moisture concentration measurements in high-purity ammonia. A near-infrared diode-laser-based instrument has been applied to measure the humidity in a process of on-line detection of water in ammonia during industrial purification. The results of water concentration measurements were compared with alternative techniques (primarily dew-point detection) and good agreement was achieved. The long-term sensitivity of such a diode-laser-based instrument was estimated to be 5 ppm. The calculation of the water concentration from measurements of the integrated volume of water contained in the heavy fraction, extracted during the purification process, yields an even lower detection limit of less than 0.1 ppm, depending on the initial ammonia purity. [ABSTRACT FROM AUTHOR]

Stimulated emission of radiation from CdxHg1 – xTe samples pumped by a Nd:YAG laser at temperature T ≈ 77 K is obtained. Both spontaneous and stimulated emission is observed for the wavelengths λ in the range 3300–3600 nm. Experimental emission spectra are presented. The special features of the spectra and the possible applications of the structures are discussed. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

Metalorganic chemical vapor deposition from Cd and Te alkyl compounds and Hg vapor is used to grow p-type CdxHg1 – xTe epitaxial layers on semi-insulating GaAs(111)B substrates by the interdiffused multilayer process (alternating CdTe and HgTe layers) at a substrate temperature of 350°C, followed by postgrowth annealing. Layers are obtained with x = 0.2–0.4, 77-K carrier concentrations in the range (1–5) × 1016 cm–3, and 77-K carrier mobilities from 200 to 400 cm2 /(V s). The rocking curves of the epilayers have a full width at half maximum in the range 2–4 min of arc. [ABSTRACT FROM AUTHOR]

The article focuses on a study carried out to produce and purify silanes, 29SiH4 and 30SiH4, of high isotopic and chemical purity. It states that higher chemical purity with a higher content of the main isotope are required to study the chemical properties of silanes. It describes how the silanes were analyzed by gas chromatography method and the isotopic composition of silanes was determined by laser mass spectrometry.

The results are reported on the observation of the induced emission from CdxHg1 – xTe samples optically pumped by a pulsed Nd:YAG laser at temperatures T < 77 K. In the wave range λ∼3300–3600 nm, both stimulated and spontaneous emission were observed. The experimentally measured emission spectra are analyzed. The properties of the spectra from the samples are discussed and the possible applications are considered. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]