Кандидаты на представление к званию «Почетный член ВМСО»
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Дискриминация газовых компонентов и кластеров
One of the serious problems in analytical mass spectrometry is the interferences between clusters and gas components and components of sample. These interferences make parameters of mass spectral analysis worse. The present paper describes a new approach for the reduction of such interferences by using pulsed glow discharge which allows the temporal discrimination of interfering components. Infl uence of hydrogen on dynamic discrimination of various gas components is considered. It was possible to decrease the relative intensity of gas and clusters components by several orders of magnitude. In particular, optimum conditions (pressure in discharge cell, addition of hydrogen, repelling pulse delay) allow effective suppressing the 40 Ar + component which makes possible the measurement calcium in metallurgical silicon.
Оценка неопределенности измерения изотопного состава высокообогащенного 28Si
A technique for uncertainty estimation of an isotopic composition of highly enriched silicon-28 in the form of a single crystal, silicon tetrafl uoride and silane by laser ionization mass spectrometry is described. It is shown that the use of potassium as an internal standard limits the uncertainty of measurement due to the uncertainty of silicon isotopes tabulated abundances. It is found that interferences of the ions 28 SiH+ on 29 Si + should be taken into consideration during direct measurements of isotopic composition of poly- and single crystals of highly enriched silicon-28. The contribution of the 28 SiH+ to the 29 Si + peak intensity is estimated.
Квадрупольный фильтр масс с малой низкочастотной временной гармоникой электрического поля
Upper stability island created by auxiliary RF voltage with small amplitude and low frequency ν = ω/Ω = 1/10 is investigated. The possibility of operation of quadrupole mass fi lter with high transmission 50 % and high resolution about R0.1 = 3000 is demonstrated. Phase shift synchronization, ion cooling by buffer gas in RF quadrupole, and time fl ight through fringing fi eld optimization are required for achievement of such parameters.
Масс-спектрометрическое изучение термолиза комплексов включения
Thermolysis of inclusion complexes «β-cyclodextrin-benzene carboxylic acid» has been studied by temperature-programmed desorption mass spectrometry. Thermal decomposition of inclusion compounds was proved to proceed in two steps: the release of benzene carboxylic acid in molecular form from inner hydrophobic cavity of β-cyclodextrin and thermal decomposition of β-cyclodextrin.
О точности определения изотопного состава легких элементов
The performance of isotope ratio mass spectrometry systems (GC-C-IRMS, EA-IRMS, TC/EA-IRMS, DI-IRMS) with respect to dependence of δ13 C, δ15 N, δ18 O values on the amount of sample was presented. Various amounts of gas, liquid and solid samples were used for introducing to the mass spectrometry systems. The main reasons of non-linear dependence of measured isotope ratios on decreasing sample amounts appeared to be the presence of water in the ion source, imperfect optimization of ion source, and scattering of ions by molecules of gas-contaminants.
Хроматомасс-спектрометрическая идентификация примесей
Impurities in high-purity carbon tetrachloride were identifi ed by gas chromatography/ mass spectrometry. The identifi cation was accomplished by comparison of experimental mass spectra with the spectra in NIST-2005 database. For concentrations, close to the limit of detection, the nature of impurities was determined using selective ion monitoring and retention times of the corresponding substances. For the fi rst time sulfur, 2 bromochloromethanes, hexachlorocyclopropane, saturated hydrocarbons C6–C18 and some aromatic impurities were identifi ed. Totally 41 impurity substances were found.
Использование изотопной масс-спектрометрии для оценки масштабов эмиссии биогенного метана в атмосферу
The biogeochemical studies of bacterial methanogenesis and methane oxidation processes occurring at a dump of solid domestic waste (SDW) of the city of Kaluga have been performed. The dump contains about 1.357×106 tons of non-toxic domestic waste buried with successive application of sand-clay and waste layers. On the basis of quantitative and isotopic characteristics of the carbon from methane and carbon dioxide, it has been determined that about (3.33±1.31)×106 m3 of methane is released into the atmosphere each year at burial of wastes in the amount of 37.17×103 tons year –1 . The effi ciency of methane-oxidizing bacterial fi lter on the SDW ground with sand-clay layers is estimated as approximately 23 % of total methane production. After partial oxidation of biogenic methane by methanotrophic bacteria, isotopic composition of the carbon emitted into atmosphere is characterized by the value of δ13 С = –(45.6±2.5) ‰.
