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111.
112.
Svante Vikingsson Malin Strömqvist Anna Svedberg Johan Hansson Veronica Höiom Henrik Gréen 《Biomedical chromatography : BMC》2016,30(8):1234-1239
A novel, rapid and sensitive liquid chromatography tandem–mass spectrometry method for quantification of vemurafenib in human plasma, that also for the first time allows for metabolite semi‐quantification, was developed and validated to support clinical trials and therapeutic drug monitoring. Vemurafenib was analysed by precipitation with methanol followed by a 1.9 min isocratic liquid chromatography tandem masspectrometry analysis using an Acquity BEH C18 column with methanol and formic acid using isotope labelled internal standards. Analytes were detected in multireaction monitoring mode on a Xevo TQ. Semi‐quantification of vemurafenib metabolites was performed using the same analytical system and sample preparation with gradient elution. The vemurafenib method was successfully validated in the range 0.5–100 μg/mL according to international guidelines. The metabolite method was partially validated owing to the lack of commercially available reference materials. For the first time concentration levels at steady state for melanoma patients treated with vemurafenib is presented. The low abundance of vemurafenib metabolites suggests that they lack clinical significance. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
113.
114.
Gaikwad AV Holuigue A Thathagar MB ten Elshof JE Rothenberg G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(24):6908-6913
Leaching of palladium species from Pd nanoparticles under C--C coupling conditions was observed for both Heck and Suzuki reactions by using a special membrane reactor. The membrane allows the passage of palladium atoms and ions, but not of species larger than 5 nm. Three possible mechanistic scenarios for palladium leaching were investigated with the aim of identifying the true catalytic species. Firstly, we examined whether or not palladium(0) atoms could leach from clusters under non-oxidising conditions. By using our membrane reactor, we proved that this indeed happens. We then investigated whether or not small palladium(0) clusters could in fact be the active catalytic species by analysing the reaction composition and the palladium species that diffused through the membrane. Neither TEM nor ICP analysis supported this scenario. Finally, we tested whether or not palladium(II) ions could be leached in the presence of PhI by oxidative addition and the formation of [Pd(II)ArI] complexes. Using mass spectrometry, UV-visible spectroscopy and 13C NMR spectroscopy, we observed and monitored the formation and diffusion of these complexes, which showed that the first and the third mechanistic scenarios were both possible, and were likely to occur simultaneously. Based on these findings, we maintain that palladium nanoparticles are not the true catalysts in C--C coupling reactions. Instead, catalysis is carried out by either palladium(0) atoms or palladium(II) ions that leach into solution. 相似文献
115.
Erik J. Faber Dr. Wouter Sparreboom Wilrike Groeneveld Louis C. P. M. de Smet Dr. Johan Bomer Wouter Olthuis Dr. Han Zuilhof Dr. Ernst J. R. Sudhölter Prof. Piet Bergveld Prof. Albert van den Berg Prof. 《Chemphyschem》2007,8(1):101-112
The electrochemical behavior of Si--C linked organic monolayers is studied in electrolyte-insulator-Si devices, under conditions normally encountered in potentiometric biosensors, to gain fundamental knowledge on the behavior of such Si electrodes under practical conditions. This is done via titration experiments, Mott-Schottky data analysis, and data fitting using a site-binding model. The results are compared with those of native SiO(2) layers and native SiO(2) layers modified with hexamethyldisilazane. All samples display pH sensitivity. The number of Si--OH groups on the alkylated samples is calculated to be less than 0.7 % of that of a pure SiO(2) insulator, which still causes a pH sensitivity of approximately 25 mV per pH unit in the pH range: 4-7. The alkylated samples hardly suffer from response changes during up- and down-going titrations, which indicates that very little oxide is additionally formed during the measurements. The pK(a) values of all samples with monolayers (4.0-4.4) are lower than that of native SiO(2) (6.0). The long-term drift (of approximately 1 mV h(-1)) is moderate. The results indicate that biosensors composed of alkylated Si substrates are feasible if a cross-sensitivity towards pH in the sensor signal is taken into account. 相似文献
116.
The synthesis, spectroscopic, electrochemical and photophysical characterization of a series of dinuclear ruthenium(II) complexes of the type [(bpy)2Ru(NnN)2RuCl(bpy)2](PF6)3, where NnN = 4,4′‐bipyridyl (N0N), 1,2‐bis(4‐pyridyl)ethylene (NEN), 1,2‐bis(4‐pyridyl)ethane (N2N), and 4,4′‐trimethylenedipyridine (N3N) are reported. The photophysical and electrochemical properties are discussed with particular emphasis on the ability of the bridging ligands to support intercomponent interaction. 相似文献
117.
Smith BE Sutton PA Lewis CA Dunsmore B Fowler G Krane J Lutnaes BF Brandal Ø Sjöblom J Rowland SJ 《Journal of separation science》2007,30(3):375-380
Examination by high temperature GC (HTGC) of the methyl esters of the so-called 'ARN' naphthenic acids from crude oils of North Sea UK, Norwegian Sea and West African oilfields revealed the distributions of resolved 4-8 ring C80 tetra acids and trace amounts of other acids. Whilst all three oils contained apparently the same major acids, the proportions of each differed, possibly reflecting the growth temperatures of the archaebacteria from which the acids are assumed to have originated. The structures of the 4, 5, 7 and 8 ring acids are tentatively assigned by comparison with the known 6 ring acid and related natural products and an HPLC method for the isolation of the individual acids is described. ESI-MS of individual acids isolated by preparative HPLC established the elution order of the 4-8 ring acids on the HPLC and HTGC systems and revealed the presence of previously unreported acids tentatively identified as C81 and C82 7 and 8 ring analogues. 相似文献
118.
We present analytical results on the so-called end-evaporation kinetics in equilibrium polymeric systems following a temperature jump (T jump). A T jump prepares the system with a nonequilibrium length distribution, after which it relaxes back to its equilibrium state. Starting from a master equation, we develop a mean-field analytical theory based on a generating function approach, which allows explicit approximate expressions for the monomer and dimer concentrations to be derived in a discrete setting; the concentrations of the other chains as well as the average chain length were shown to be entirely expressible in terms of the monomer and dimer concentrations. We find that the calculated monomer and dimer concentrations as well as the average chain length are in good agreement with numerical simulation results and do not suffer from some of the defects of earlier continuum theories. Furthermore, the relaxation was shown to take place in three different stages. The first stage comprises the very fast relaxation of the monomers to almost their equilibrium concentration; the other polymer chains have hardly relaxed. During the second stage, which is highly nonlinear, a redistribution of material at practically constant monomer density takes place. Only in the final stage of the relaxation process the chain concentrations approach their true equilibrium values. In this stage there are only very small shifts in the concentrations of chains, which are governed by extremely slow "indirect" monomer-mediated processes. 相似文献
119.
Synthesis and Thermophysical Properties of Ether‐Functionalized Sulfonium Ionic Liquids as Potential Electrolytes for Electrochemical Applications 下载免费PDF全文
Dr. Erwan Coadou Dr. Peter Goodrich Alex R. Neale Dr. Laure Timperman Prof. Christopher Hardacre Dr. Johan Jacquemin Prof. Mérièm Anouti 《Chemphyschem》2016,17(23):3992-4002
During this work, a novel series of hydrophobic room temperature ionic liquids (ILs) based on five ether functionalized sulfonium cations bearing the bis{(trifluoromethyl)sulfonyl}imide, [NTf2]? anion were synthesized and characterized. Their physicochemical properties, such as density, viscosity and ionic conductivity, electrochemical window, along with thermal properties including phase transition behavior and decomposition temperature, have been measured. All of these ILs showed large liquid range temperature, low viscosity, and good conductivity. Additionally, by combining DFT calculations along with electrochemical characterization it appears that these novel ILs show good electrochemical stability windows, suitable for the potential application as electrolyte materials in electrochemical energy storage devices. 相似文献
120.
Dr. Yanhui Wang Dr. Sanghoon Kim Dr. Nicolas Louvain Dr. Johan G. Alauzun Dr. P. Hubert Mutin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(18):4767-4774
An original, halide-free non-hydrolytic sol–gel route to mesoporous anatase TiO2 with hierarchical porosity and high specific surface area is reported. This route is based on the reaction at 200 °C of titanium(IV) isopropoxide with acetic anhydride, in the absence of a catalyst or solvent. NMR spectroscopic studies indicate that this method provides an efficient, truly non-hydrolytic and aprotic route to TiO2. Formation of the oxide involves successive acetoxylation and condensation reactions, both with ester elimination. The resulting TiO2 materials were nanocrystalline, even before calcination. Small (about 10 nm) anatase nanocrystals spontaneously aggregated to form mesoporous micron-sized particles with high specific surface area (240 m2 g−1 before calcination). Evaluation of the lithium storage performances shows a high reversible specific capacity, particularly for the non-calcined sample with the highest specific surface area favouring pseudo-capacitive storage: 253 mAh g−1 at 0.1 C and 218 mAh g−1 at 1 C (C=336 mA g−1). This sample also shows good cyclability (92 % retention after 200 cycles at 336 mA g−1) with a high coulombic efficiency (99.8 %). Synthesis in the presence of a solvent (toluene or squalane) offers the possibility to tune the morphology and texture of the TiO2 nanomaterials. 相似文献