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1.
I. A. Anan'eva E. N. Myshak E. N. Shapovalova O. A. Shpigun 《Journal of Analytical Chemistry》2003,58(5):461-466
The retention and separation of optical isomers of amino acid derivatives on aminated -cyclodextrin was studied. The pH dependence of the distribution coefficients of these derivatives in the octanol–water system was found. It was demonstrated that the capacity factors and the enantioselectivity of the separation of amino acid derivatives depend on the hydrophobicity of the studied compounds. 相似文献
2.
O. A. Filippov V. V. Posokh T. I. Tikhomirova E. N. Shapovalova G. I. Tsizin O. A. Shpigun Yu. A. Zolotov 《Journal of Analytical Chemistry》2002,57(9):788-793
Conditions of the preconcentration of phenol on a microcolumn filled with MN-200 hypercrosslinked polystyrene were determined using the linear sorption dynamics model. Conditions of the on-line determination of phenol and its chloro derivatives by reversed-phase high-performance liquid chromatography with amperometric detection were optimized. The detection limit of phenol and chlorophenols for preconcentration from 30 mL of a sample was 3 and 15 ng/L, respectively. The proposed procedure was used for the determination of phenols in tap and river water. 相似文献
3.
M. G. Chernobrovkin I. A. Anan'eva E. N. Shapovalova O. A. Shpigun 《Journal of Analytical Chemistry》2004,59(1):55-63
Precolumn derivatization with the reagent o-phthalic aldehyde/N-acetyl-L-cysteine (OPA/NAC) was used for the determination of amino acid enantiomers by reversed-phase high-performance liquid chromatography. The influence of the composition and pH of the eluent on the separation of the resulting derivatives was studied with the example of four amino acids. It was found that the highest selectivity and efficiency of the separation of OPA/NAC derivatives of amino acids is attained with the use of the eluent methanol–0.01 M Na2HPO4 (pH 6.0). The optimum composition of the mobile phase and conditions of the gradient elution were selected for the separation of a mixture of 20 amino acid derivatives. A procedure was developed for the determination of amino acid enantiomers in parenteral nutrition preparations. The procedure was used for the determination of D-isomers of arginine, alanine, methionine, phenylalanine, and leucine in the preparation Polyamine. 相似文献
4.
N. M. Pogosyan M. Dj. Pogosyan O. V. Shapovalova A. V. Nikitin V. S. Arutyunov 《Russian Journal of Physical Chemistry B, Focus on Physics》2016,10(6):907-911
The feasibility of the production of ethylene and heavier olefins by introducing methane into the products of a rich methane flame is experimentally demonstrated. Such a process is promising for the direct production of ethylene, propylene, and heavier olefins directly from methane, the main component of natural gas. 相似文献
5.
Sulyaeva V. S. Gatapova E. Ya. Kozhevnikov A. K. Rogilo D. I. Saraev A. A. Yushina I. V. Khomyakov M. N. Shapovalova A. A. Shayapov V. R. Bhaskar N. Tu R. Kosinova M. L. 《Journal of Structural Chemistry》2021,62(8):1309-1324
Journal of Structural Chemistry - We report a comprehensive study of the effect of the chemical structure of boron carbonitride films on the variability of their functional characteristics. The... 相似文献
6.
We conduct a case study in which we empirically illustrate the performance of different classes of Bayesian inference methods to estimate stochastic volatility models. In particular, we consider how different particle filtering methods affect the variance of the estimated likelihood. We review and compare particle Markov Chain Monte Carlo (MCMC), RMHMC, fixed-form variational Bayes, and integrated nested Laplace approximation to estimate the posterior distribution of the parameters. Additionally, we conduct the review from the point of view of whether these methods are (1) easily adaptable to different model specifications; (2) adaptable to higher dimensions of the model in a straightforward way; (3) feasible in the multivariate case. We show that when using the stochastic volatility model for methods comparison, various data-generating processes have to be considered to make a fair assessment of the methods. Finally, we present a challenging specification of the multivariate stochastic volatility model, which is rarely used to illustrate the methods but constitutes an important practical application. 相似文献
7.
S. G. Dmitrienko E. N. Shapovalova E. Ya. Gurarii M. V. Kochetova O. A. Shpigun Yu. A. Zolotov 《Journal of Analytical Chemistry》2002,57(11):1009-1016
A technique was developed for the sorption preconcentration of polycyclic aromatic hydrocarbons on polyurethane foams in the batch and dynamic modes providing their simultaneous quantitative extraction. A procedure was proposed for screening waters for polycyclic aromatic hydrocarbons based on the preconcentration of these compounds with polyurethane foam, determination of their total amount by the luminescence method, desorption of adsorbed compounds with acetonitrile, and determination of individual compounds in the eluate by high-performance liquid chromatography with fluorescence detection. The procedure was tested with model and real samples of water. 相似文献
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9.
A mixed chiral sorbent based on silica with immobilized macrocyclic antibiotics eremomycin and vancomycin was synthesized. A possibility of the separation of enantiomers of β-blockers (metoprolol, pindolol, alprenolol, oxprenolol, labetalol, and atenolol) and amino acids (tryptophan, phenylalanine, DOPA, methionine, and acetyl glutamic acid) on this chiral sorbent by HPLC was studied. The influence of the composition of the mobile phase (pH of buffer solution, its concentration, content of organic modifier, and its nature) on the retention times of β-blocker and amino acid enantiomers, selectivity, and resolution of peaks was studied. It was shown that the mixed chiral sorbent has enantioselectivity to both classes of compounds, while silica modified with vancomycin has no ability to the separation of enantiomers of non-derivatized amino acids, and silica modified with eremomycin has no ability to the separation of β-blocker enantiomers. High values of resolution for amino acids (max Rs > 4) and β-blockers (max Rs > 1) were obtained. 相似文献
10.
Features of the separation of pesticides of different classes by reversed-phase high-performance chromatography 总被引:1,自引:0,他引:1
The effect of the concentration and the nature of an organic modifier, the composition of a buffer solution, and the pH of the mobile phase on the efficiency and selectivity of the separation of some pesticides (difenoconazole, propiconazole, penconazole, fludioxonil, thiram, 2,4-dichlorophenoxyacetic acid, linuron, lenacil, benomyl, acetamiprid, chlorsulfoxime, rimsulfuron, chlorsulfuron, and dicamba) on a Diaspher C16 silica gel were examined. The dependence of the retention on the hydrophobicity of these pesticides were compared. The possibility of the group separation and determination of pesticides with the use of the mobile phase acetonitrile-phosphate buffer solution (0.01 M, pH 4.2) (40: 60) was demonstrated. 相似文献