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排序方式: 共有173条查询结果,搜索用时 21 毫秒
1.
Pipíška Martin Florková Eva Nemeček Peter Remenárová Lucia Horník Miroslav 《Journal of Radioanalytical and Nuclear Chemistry》2019,319(3):855-867
Journal of Radioanalytical and Nuclear Chemistry - Zeolitic material prepared by hydrothermal treatment of brown coal fly ash was used for sorption separation of Co2+ and Zn2+ ions from single and... 相似文献
2.
Lenka Škantárová Andrej Oriňák Renáta Oriňáková Monika Jerigová Monika Stupavská Dušan Velič 《Surface and interface analysis : SIA》2013,45(8):1266-1272
Present article deals with functionality of silver nanostructured surfaces prepared by potentiostatic electrochemical deposition on the paraffin impregnated graphite electrode as template‐free substrates. The effect of the electrodeposition conditions on two silver surface functions: analytical signal enhancement in Surface‐enhanced Raman spectroscopy and pre‐ionization function, applied in secondary ion mass spectrometry (SIMS) is reported. Functional silver nanostructured substrate was prepared at a potential ?850 mV with a deposition duration of 20 min. Analytical signal enhancement factors of 3.2 ×105 for Raman peak at 649 cm?1, 3.0×105 for peak at 810 cm?1 and 2.7×105 for peak at 1539 cm?1 were determined for Rhodamine 6G at deposited surface. Slight pre‐ionization effect has been observed in SIMS, and 1.2×105 fold signal enhancement was established for fragment of Rhodamine 6G with m/z 429 (M‐CH3‐Cl). Electrochemical preparation of nanostructures represents a step towards surface integration directly into miniaturized systems and sensors. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
3.
4.
This review summarizes all significant data regarding peroxynitrite chemistry, the ways of its synthetic preparation as well
as the degradative action of this species on biomolecules, in particular glycosaminoglycans, among which the hyaluronan degradation
by peroxynitrite has recently been the subject of greater interest than ever before. The complex chemical behavior of a peroxynitrite
molecule is strongly influenced by a few factors; conformational structural forms, active intermediates release, presence
of CO2 and trace transition metals, different reaction conditions, as well as the rules of kinetics. Special attention was focused
on monitoring of the kinetics of the degradative action of peroxynitrite in or without the presence of residual hydrogen peroxide
on high-molar-mass hyaluronan. 相似文献
5.
6.
The distribution of chelate-forming reagents on a basis of arylimidodiphosphate between different organic solvents and 0.1
mol L−1 HNO3 has been studied by liquid-liquid extraction of 46Sc. The values of dimerization constants K2 in selected solvents, particularly on the chlorine and chlorine-fluorine hydrocarbon basis as well as distribution constants
KD(HA) have been determined. 相似文献
7.
8.
In this contribution, the on-line coupling of solid phase extraction (SPE), based on a restricted-access material (RAM), with sequential injection technique (SIA) for the analysis of biological samples, is described. The SIA-RAM system was tested with a new potential antileucotrienic drug (VUFB-19363 (Quinlukast)) for serum analysis. The method is based on SPE with the novel internal-surface reversed-phase column packing material-alkyl-diol silica (ADS). The supports tolerate direct and repetitive injection of proteinaceous fluids (plasma, serum) and allow reversed-phase partitioning at the internal surface. A column packed with a 25 microm C18 alkyl-diol support was used for direct serum injection. Using a 6-port selection valve and the system of three mobile phases, the polar matrix compounds and metabolites are removed by sequentially aspirated mobile phases with lower content of the organic part (methanol-water (2:98) and following acetonitrile-water (20:80)) to the waste, and then, the analyte enriched on the column is eluted by a strong mobile phase (acetonitrile-methanol-water (40:20:40)) to the UV detector without transfer loss. With the fully automated SIA system, a total analysis time of less than 10 min was achieved. The only off-line sample pre-treatment step required to remove particulate matter was centrifugation. The studies showed a range of linearity (2-40 microg ml(-1)) and a high recovery (93.6-96.8%) of drug from the biological matrix with coefficients of variation (RSD) less than 5.0% (n = 6). This paper introduces a new, simple and robust analytical technique suitable for screening determination and direct analysis of drugs in biological materials. 相似文献
9.
S. D. Chepik V. F. Cherstkov E. I. Mysov A. F. Aérov M. V. Galakhov S. R. Sterlin L. S. German 《Russian Chemical Bulletin》1991,40(11):2285-2291
An unusual electrophilic cyclization of fluorine-containing carbonyl compounds and -oxides was discovered. Upon the action of SbF5, perfluorinated ketones, diketones, and -oxides isomerize to oxolanes. This reaction proceeds with the obligatory participation of the terminal CF3 group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2611–2618, November, 1991. 相似文献
10.
Jarmila Štetinová Rudolf Kada Miloslava Dandárová Marcela Krublová Ján Leśko 《Chemistry of Heterocyclic Compounds》1995,31(10):1231-1233
Substituted ]-(6-methoxy-2-benzothiazolyt)-2-pyridones were prepared from 2-amino-6-methoxybenzathiazate through N-(6-methoxy-2-benzothiazotyl) cyanvorearmileaznd-3-aryl-N-(6-methoxy-2-benzothiazolyt)-2-cyano-2-propenamides. The cyclization of the latter with malonodinitrile in the presence of piperidine gave the corresponding pyridones. The structures of the synthesized compounds were confirmed by1H NMR and mass spectral data.Department of Organic Chemistry, Mass Spectrometry Laboratory, Slovak Technical University, 812 37 Bratislava, Slovakia. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1402–1404, October, 1995. Original article submitted August 24, 1995. 相似文献