72 research outputs found
СОРБЦИОННО-ХРОМАТОГРАФИЧЕСКОЕ ОПРЕДЕЛЕНИЕ ГАЛЛОВОЙ, КОФЕЙНОЙ КИСЛОТ, РУТИНА И ЭПИКАТЕХИНА В ЛЕКАРСТВЕННЫХ РАСТЕНИЯХ
The sorption processes of solid-phase extraction of phenolic compounds from water extracts of medicinal herbs followed by chromatographic technique have been studied. Using model aqueous solutions and water extracts of Hypericum perforatum and Achillea millefolium the Diapak C18 recoveries overcome versus Diapak P (hypercross-linked polystyrene) and liquid-liquid extraction technique. The conditions of sorption extraction and determination of gallic acid, trans-caffeic acid and rutin using the sorbent Diapak C18 were optimized.Key words: solid-phase extraction (SPE), high-performance liquid chromatography (HPLC), phenolic compounds, medicinal herbs(Russian)DOI: http://dx.doi.org/10.15826/analitika.2013.17.2.012Z.A. Temerdashev, V.V. Milevskaya, N.V. Kiseleva, N.A. Vernikovskaya,V.А. Korobkov Kuban State University, Krasnodar, Russian FederationИзучены сорбционные процессы извлечения фенольных соединений из водных отваров образцов лекарственного растительного сырья (ЛРС) для их последующего хроматографического определения. На примере анализа модельных растворов и водных отваров зверобоя продырявленного и тысячелистника обыкновенного показано, что степени извлечения фенольных соединений с использованием концентрирующего патрона Диапак С18 выше по сравнению с сорбентом Диапак П (сверхсшитый полистирол) и вариантом использования жидкость-жидкостной экстракции. Оптимизированы условия сорбции и определения галловой, кофейной кислот и рутина с использованием сорбента Диапак С18.Ключевые слова: твердофазная экстракция (ТФЭ), высокоэффективная жидкостная хроматография (ВЭЖХ), фенольные соединения, лекарственное растительное сырье.DOI: http://dx.doi.org/10.15826/analitika.2013.17.2.01
Early Ediacaran Magmatism in the Yenisei Ridge and Evolution of the Southwestern Margin of the Siberian Craton
We present the first comprehensive data for the early Ediacaran stage of evolution of the western active continental margin of the Siberian Craton (Yenisei Ridge). U-Pb (SHRIMP-II SIMS) data for zircons from dikes of picrodolerites, quartz diorites, and leucocratic granites show that they were emplaced at 625 ± 5, 623 ± 8, and 626 ± 5 Ma, respectively, which indicates a narrow time window of Ediacaran magmatic events. The mafic tholeiitic rocks have OIB and E-MORB mantle components in their magmatic sources. Mineralogical and geochemical observations showed that the mantle-sourced mafic melts assimilated some crustal material, forming Th-enriched dikes of intermediate composition and K- and Rb-enriched felsic rocks. The possible geodynamic conditions for the formation of these early Ediacaran dikes are shown and a geodynamic model is presented for the development of the Yenisei Ridge orogen from the late Cryogenian to the late Ediacaran
MATHEMATICAL MODELLING FOR OXIDATION PROCESS OF SULPHUR DIOXIDE IN ARTIFICIAL-CREATED NON-STATIONARY CONDITIONS TAKING DYNAMIC PROPERTIES OF CATALYST INTO CONSIDERATION
The mathematical model of the catalytic reactors for oxidation process of the sulphur dioxide taking non-stationary state of the catalyst into cosideration that is new has been developed. The fields of the parameters in which the use of the kinetic models obtained in the conditions of the quasi-stationary approximation is admissible have been determined; the new technological scheme has been proposed and investigatedAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio
Common solid speech errors made by students in their polish classes
It deals with a classification of common solid errors made by students in grammar constructions of the Polish language and it provides the information that learners need to correct their grammar errors. Moreover, it states the necessity to work out not Polish but Polish and Russian grammar rules based on the comparison between the mother tongue and a foreign language
Early Ediacaran Magmatism in the Yenisei Ridge and Evolution of the Southwestern Margin of the Siberian Craton
A tectonothermal model for the formation of an orogen at the post-collisional stage (by the example of the Yenisei Ridge, Eastern Siberia)
Model-Based Performance Analysis of Membrane Reactor with Ethanol Steam Reforming over a Monolith
Membrane reactors (MR) with an appropriate catalyst are considered to be an innovative and intensified technology for converting a fuel into the hydrogen-rich gas with the simultaneous recovery of high-quality hydrogen. Characteristics of an asymmetric membrane disk module consisting of a gas-tight nanocomposite functional coating (Ni + Cu/Nd5.5WO11.25-δ mixed proton-electron conducting nanocomposite) deposited on a gas-permeable functionally graded substrate has previously been extensively studied at lab-scale using MRs, containing the catalyst in a packed bed and in the form of a monolith. The catalytic monolith consisted of a FeCrAl substrate with a washcoat and an Ni + Ru/Pr0.35Ce0.35Zr0.35O2 active component. It has been shown that the driving potential for hydrogen permeation across the same membrane in a monolithic catalyst –assisted MR is greater compared to the packed bed catalyst. This paper presents results of the study where a one-dimensional isothermal model was used to interrelate catalytic and permeation phenomena in a MR with ethanol steam reforming over the monolith, operating at atmospheric pressure and in the temperature range of 700–900 °C. The developed mathematical reaction–transport model for the constituent layers of the catalyst-asymmetric membrane assembly together with a Sieverts’ equation for the functional dense layer, taking also into account the effect of boundary layers, was implemented in a COMSOL Multiphysics environment. Good agreement with the experimental data of the lab-scale MR with reasonable parameters values is provided. In numerical experiments, concentration profiles along the reactor axis were obtained, showing the effect of the emerging concentration gradient in the boundary layer adjacent to the membrane. Studies have shown that a MR with a catalytic monolith along with appropriate organization of a stagnant feed flow between the monolith and the membrane surface may enhance production and flux of hydrogen, as well as the efficiency characteristics of the reactor compared to a reactor with packed beds
Effect of Asymmetric Membrane Structure on Hydrogen Transport Resistance and Performance of a Catalytic Membrane Reactor for Ethanol Steam Reforming
The performance of catalytic membrane reactors (CMRs) depends on the specific details of interactions at different levels between catalytic and separation parts. A clear understanding of decisive factors affecting their operational parameters can be provided via mathematical simulations. In the present paper, main results of numerical studies of ethanol steam reforming, followed by downstream hydrogen permeation through an asymmetric supported membrane, are reported. The membrane module consists of a thin selective layer supported on a substrate with graded porous structure. One-dimensional isothermal reaction–transport model for the CMR has been developed, and its validation has been carried out by using performance data from a lab-scale reactor with a disk-shaped membrane. Simulations demonstrate the model’s capabilities to analyze local concentrations gradients, as required to provide accurate estimates of the relationship between structure–property–performance. It was shown that transport properties of multilayer asymmetric membranes are highly related to the structural properties of each single layer
Identification and chromatographic determination of phenolic compounds in yarrow
Предложена схема анализа водных экстрактов тысячелистника обыкновенного, включающая идентификацию фенольных соединений и флавоноидов методами газовой и жидкостной хромато-масс-спектрометрии и их определение методом высокоэффективной жидкостной хроматографии (ЖХ-МС). На основе предложенной схемы методом газовой хромато-масс-спектрометрии в тысячелистнике идентифицированы фенольные соединения, относящиеся к классам фенолкарбоновых, коричных и кофеилхинных кислот. Методом ЖХ-МС идентифицированы 6 соединений группы кофеилхинных кислот. С помощью высокоэффективной жидкостной хроматографии с УФ-детектированием на диодной матрице определено содержание 8 фенольных соединений: протокатеховой, транс-кофейной, 3-О-кофеилхинной, 5-О-кофеилхинной, 4-О-кофеилхинной, 3,4-О-дикофеилхинной, 3,5-О-дикофеилхинной и 4,5-О-дикофеилхинной кислот.A scheme for analysis of aqueous extracts of yarrow including the identification of phenolic compounds and flavonoids by gas and liquid chromatography mass spectrometry and their determination by high performance liquid chromatography was proposed. On the basis of the scheme phenolic compounds (phenolcarbonic, cinnamic and caffeoylquinic acids) were identified in yarrow by GC-MS. Six caffeoylquinic acids were identified by. The content of eight phenolic compounds (protocatechuic, trans-caffeic, 3-O-caffeoylquinic, 5-O-caffeoylquinic, 4-O-caffeoylquinic, 3,4-O-caffeoylquinic, 3,5-O-caffeoylquinic and 4,5-O-caffeoylquinic acids) were determined in yarrow using HPLC-UV-DAD
Early ediacaran magmatism in the yenisei ridge and evolution of the southwestern margin of the siberian craton
We present the first comprehensive data for the early Ediacaran stage of evolution of the western active continental margin of the Siberian Craton (Yenisei Ridge). U-Pb (SHRIMP-II SIMS) data for zircons from dikes of picrodolerites, quartz diorites, and leucocratic granites show that they were emplaced at 625 ± 5, 623 ± 8, and 626 ± 5 Ma, respectively, which indicates a narrow time window of Ediacaran magmatic events. The mafic tholeiitic rocks have OIB and E-MORB mantle components in their magmatic sources. Mineralogical and geochemical observations showed that the mantle-sourced mafic melts assimilated some crustal material, forming Th-enriched dikes of intermediate composition and K-and Rb-enriched felsic rocks. The possible geodynamic conditions for the formation of these early Ediacaran dikes are shown and a geodynamic model is presented for the development of the Yenisei Ridge orogen from the late Cryogenian to the late Ediacaran
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