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Ignacio Alfonso Covadonga Astorga Vicente Gotor 《Journal of inclusion phenomena and macrocyclic chemistry》2005,53(1-2):131-137
Electrospray ionization mass espectrometry (ESI-MS) has been used for the study of a cyclam derivative noncovalent interactions.
At acidic pH, diprotonated macrocycle bound to different anionic species were observed. The selectivity shown by competitive
experiments is rationalized with the help of semiempirical theoretical calculations. At basic pH, the base peak corresponded
to the macrocycle-alkaline metal complexes, and again competition experiments showed different binding strength. Finally,
experiments carried out in the presence of transition metal salts allowed the detection of the complexes present in the mixture
and revealed their different kinetic behavior. 相似文献
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Dr. Teresa Hungría Covadonga Correas Dr. Florent Houdellier Dr. Octavio Peña Dr. Eladio Vila Prof. Dr. Alicia Castro 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(29):9075-9082
In the last ten years, the study and the search for new multiferroic materials have been a major challenge due to their potential applications in electronic technology. In this way, bismuth‐containing perovskites (BiMO3), and particularly those in which the metal M position is occupied by a magnetically active cation, have been extensively investigated as possible multiferroic materials. From the point of view of synthesis, only a few of the possible bismuth‐containing perovskites can be prepared by conventional methods but at high pressures. Herein, the preparation of one of these potential multiferroic systems, the solid solution xBiMnO3‐(1?x)PbTiO3 by mechanosynthesis is reported. Note that this synthetic method allows the oxides with high x values, and more particularly the BiMnO3 phase, to be obtained as nanocrystalline phases, in a single step and at room temperature without the application of external pressure. These results confirm that, in the case of Bi perovskites, mechanosynthesis is a good alternative to high‐pressure synthesis. These materials have been studied from the point of view of their structural characteristics by precession electron diffraction and magnetic property measurements. 相似文献
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Covadonga Alvarez 《Talanta》2009,79(2):280-283
A sensitive and specific and automated liquid chromatography-electrospray mass spectrometric (LC-ESI-MS) assay for the quantification of Cyclosporin A in human plasma was developed. Following a simple protein precipitation step, the supernatant was extracted on-line and directly injected into the system LC-ESI-MS. A relatively new type of monolithic column consisting of a silica rod with bimodal pore structure was used to achieve a retention time of 2.4 min with a very low backpressure at a flow rate of 1 ml/min. The assay was linear from 0.050 to 1.000 μg/ml. The mean recovery was 91%. The mean inter-day and intra-day precisions were 1.85% and 2.83%, respectively. The combination of the automated solid phase extraction and the low retention time achieved with this columns increase the throughput and decrease the time of analysis of each sample. This technology is useful in order to improve the efficiency of the bioanalytical studies. 相似文献
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Analytical and Bioanalytical Chemistry - Localized information on a specimen is considered indispensable for deciphering biological activity. Magnetic resonance spectroscopy is a notable method... 相似文献
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Hungría T Correas C Houdellier F Peña O Vila E Castro A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(29):9075-9082
In the last ten years, the study and the search for new multiferroic materials have been a major challenge due to their potential applications in electronic technology. In this way, bismuth-containing perovskites (BiMO(3)), and particularly those in which the metal?M position is occupied by a magnetically active cation, have been extensively investigated as possible multiferroic materials. From the point of view of synthesis, only a few of the possible bismuth-containing perovskites can be prepared by conventional methods but at high pressures. Herein, the preparation of one of these potential multiferroic systems, the solid solution xBiMnO(3)-(1-x)PbTiO(3) by mechanosynthesis is reported. Note that this synthetic method allows the oxides with high x values, and more particularly the BiMnO(3) phase, to be obtained as nanocrystalline phases, in a single step and at room temperature without the application of external pressure. These results confirm that, in the case of Bi perovskites, mechanosynthesis is a good alternative to high-pressure synthesis. These materials have been studied from the point of view of their structural characteristics by precession electron diffraction and magnetic property measurements. 相似文献
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Tosin M Demydchuk Y Parascandolo JS Per CB Leeper FJ Leadlay PF 《Chemical communications (Cambridge, England)》2011,47(12):3460-3462
Early-stage intermediates in the biosynthesis of erythromycin A by Saccharopolyspora erythraea were intercepted by malonyl carba(dethia)-N-acetyl cysteamines, generated in vivo from the hydrolysis of the corresponding methyl esters. 相似文献
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Amparo Luna Covadonga Astorga Ferenc Fülöp Vicente Gotor 《Tetrahedron: Asymmetry》1998,9(24):1916-4487
(±)-cis-N-Benzyloxycarbonyl-2-aminocyclopentanol was efficiently resolved by O-acylation with Pseudomonas cepacia lipase, as was (±)-cis-N-benzyloxycarbonyl-2-aminocyclohexanol when Candida antarctica lipase was used. 相似文献
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