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81.
Sonia Lordel Florence Chapuis-Hugon Véronique Eudes Valérie Pichon 《Journal of chromatography. A》2010,1217(43):6674-6680
Molecularly imprinted sorbents were synthesized and used as selective extraction sorbents for the analysis of nitroaromatic explosives. Their synthesis by radical polymerization using organic monomers and by sol–gel approach using organosilanes was considered to develop a selective sorbent. The sol–gel approach with phenyltrimethoxysilane (PTMS) as monomer and 2,4-dinitrotoluene (2,4-DNT) as template gave the most promising results. An optimized procedure adapted to the selective treatment of aqueous samples was then developed and applied to various target explosives. For the first time four nitroaromatic compounds were retained on the molecularly imprinted silica (MIS) with extraction recoveries between 29% and 81%, while only low recoveries were obtained on the non-imprinted sorbent, thus highlighting the high degree of selectivity. The MIS was then used for the clean-up of a sample containing motor oil spiked with 2,4-DNT and 2,4,6-trinitrotoluene (2,4,6-TNT). The results were compared with those obtained using a conventional sorbent (Oasis HLB). The cleanest chromatogram obtained using the MIS emphasized the high potential of the MIS as selective sorbent. 相似文献
82.
83.
R. Mével S. Pichon L. Catoire N. Chaumeix C.-E. Paillard J.E. Shepherd 《Proceedings of the Combustion Institute》2013,34(1):677-684
The chemiluminescence originating from OH1, the excited hydroxyl radical, is one of the most extensively used diagnostics to characterize auto-ignition delay time of gaseous mixtures behind reflected shock waves. We have carried out new experiments and modeling of this diagnostic as well as analyzed previous results for hydrogen-based mixtures, including H2–O2, H2O2–H2O, H2–N2O and H2–O2–N2O. The experiments were analyzed with a detailed chemical reaction model which included mechanisms for OH1 creation, quenching and emission. Simulations of the reaction behind reflected shock waves were used to predict OH1 emission profiles and compare this with measured results as well as profiles of temperature and the ground state concentrations of OH. Analysis of OH1 rates of progress demonstrates that a quasi-steady state approximation is applicable and an algebraic model for OH1 concentrations can be derived that relates emission to the product of concentrations of O and H for H2–O2 and H2O2 mixtures and an additional contribution by the product of H and N2O when N2O is an oxidizer. 相似文献
84.
85.
The histidine-rich peptide H5WYG (GLFHAIAHFIHGGWHGLIHGWYG) was found to induce membrane fusion at physiologic pH in the presence of zinc chloride. In this study, we examined the ion selectivity of the interaction of Zn(2+) with H5WYG. This investigation was conducted by using adsorption at air/water interface and mass spectrometry. We found that a peptide-metal complex is formed with Zn(2+) ions. Electrospray ionisation-mass spectrometry (ESI-MS) reveals that the [H5WYG + Zn + 2H](4+), [H5WYG + Zn + H](3+) and [H5WYG + Zn](2+) ions, appearing by increasing the amount of Zn(2+) equivalent, correspond to a monomolecular H5WYG - Zn(2+) complex. Tandem mass spectrometry (MS/MS) provides evidence for the binding of the single Zn(2+) ion to the H(11) and H(19) and probably H(15) residues. 相似文献
86.
Derek H. R. Barton Brigitte Charpiot Elise Tran Huu Dau William B. Motherwell Claudine Pascard Clotilde Pichon 《Helvetica chimica acta》1984,67(2):586-599
The syntheses and X-Ray analyses of three pentavalent organobismuth compounds are described; one of these compounds has a novel diphenylbis(trifluoroacetato)-bismuthate anion with trigonal bipyramidal geometry and a stereochemically active lone pair. Analysis of these structures together with other data from the literature allows a mapping of the reaction coordinate for bismuth polyhedra. 相似文献
87.
A syn-anti photoisomerisation of the carbon-nitrogen double bond is responsible for the photochromic properties observed with 2-arylhydrazones of 2-substituted 1,2-diketones. We have determined the multiplicity of the excited state involved in the process and we have shown that, in the thermal back-reaction, syn-anti isomerisation takes place through rotation around the CN bond rather than through inversion of the nitrogen atom. 相似文献
88.
M C Rouan J Campestrini J B Lecaillon J P Dubois M Lamontagne B Pichon 《Journal of chromatography. A》1988,456(1):45-51
Liquid-solid extraction on disposable extraction columns (DECs) and liquid chromatography can be combined in a completely automated analyser. The Gilson ASPEC system was used to develop a procedure for the determination of CGP 6140 in plasma. Both sample preparation via C8 Bond-Elut DECs and injection were fully automatic. The fully automated system prepared the samples by performing the same operations as for a manual procedure. The DEC was first wetted with methanol, then with water. A 400-microliters volume of plasma and 40 microliters of the internal standard solution, diluted with 1 ml of water, were applied to the DEC, rinsed with 10(-2) mol/l dipotassium hydrogenphosphate and eluted from the DEC with 300 microliters of acetonitrile-methanol (50:50, v/v). The eluting strength of the eluate was reduced by dispensing 1 ml of water into each vial prior to direct injection into a Spherisorb ODS column via a 1-ml loop. This allowed the reconcentration of the extracted compounds on the top of the column, as they were injected in a large volume of solvent of lower eluting strength than the mobile phase [acetonitrile-methanol-4 x 10(-3) mol/l ammonia solution (54.5:5:40.5, v/v/v)]. Reproducibility results are presented. 相似文献
89.
Stphane Rigaut Johann Perruchon Luc Le Pichon Daniel Touchard Pierre H. Dixneuf 《Journal of organometallic chemistry》2003,670(1-2):37-44
Several ruthenium(II) mono(acetylides) trans-[Cl(dppe)2Ru---(CC)n---R] (n=1–4; R=SiMe3, H) and bis(acetylide) trans-[(dppe)2Ru(---(CC)2---R)2] (R=SiMe3, H) were selectively obtained and could be used as a new set of building blocks for rigid rod-like structures and further assemblies. Especially, the oxidative coupling of trans-[Cl(dppe)2Ru---(CC)3---H] with Cu(OAc)2 led to the formation of the first Ruthenium(II) binuclear species with 12 carbon atoms between the remote metals. This compound shows two reversible redox processes. 相似文献
90.
Afanasiev P Chouzier S Czeri T Pilet G Pichon C Roy M Vrinat M 《Inorganic chemistry》2008,47(7):2303-2311
Nickel and cobalt hexamethylenetetramine (HMTA) complexes (NO3)2Me(H2O)6(HMTA)2.4H2O were prepared and characterized structurally by single-crystal X-ray diffraction. Both compounds crystallize in the triclinic P1 space group with the same structure. The structures are three-dimensional hydrogen-bonded supramolecular frameworks containing two-dimensional cationic assemblies connected with proton acceptors, which are noncoordinated anionic species (nitrate) and neutral HMTA molecules. Thermal decomposition of these compounds under an inert atmosphere leads to the high-surface-area metal-carbon foams containing nickel and cobalt nanoparticles embedded within onionlike carbon shells. The decomposition process as studied by thermal analysis and in situ X-ray absorption spectroscopy (XAS) measurements occurs as a rapid loss of oxygen in the form of CO, beginning at temperatures as low as 323 K. As the in situ XAS study demonstrated, the evolution of nickel and cobalt coordination spheres occurs with intermediate formation of amorphous metal carbides, which subsequently decompose to the metal nanoparticles covered with carbon shells. 相似文献