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11.
Laure Laffont Laurence Maurice David Amouroux Patricia Navarro Mathilde Monperrus Jeroen E. Sonke Philippe Behra 《Analytical and bioanalytical chemistry》2013,405(9):3001-3010
We optimized a mercury (Hg) speciation extraction method for human hair in combination with species-specific isotope-dilution analysis by gas chromatography–inductively coupled plasma–mass spectrometry (GC–ICP–MS). The method was validated on human hair reference material RM (IAEA-086), which is recommended for analysis of monomethylmercury (MMHg) and inorganic mercury (IHg). Three reagents, hydrochloric acid (HCl), nitric acid (HNO3), and tetramethylammonium hydroxide (TMAH), and three extraction procedures, at ambient temperature for 12 h, microwave-assisted at 75 °C for 6 min, and oven heated at 80 °C for 2 h were tested. Extraction efficiency, recovery, and potential species transformations were evaluated for each method. The most efficient procedures, with recovery of ~90 % for each species with limited demethylation (<5 %) and methylation (0 %), were HNO3 digestion, irrespective of temperature, and microwave-assisted TMAH extraction. Acidic extraction with HCl induces significant demethylation, with production of artifacts. To correct for potential demethylation artifacts we recommend spiking with isotopically enriched standards before the extraction step. 相似文献
12.
Vicente Rodríguez-González Ricardo Gómez Mario Moscosa-Santillan Jacques Amouroux 《Reaction Kinetics and Catalysis Letters》2007,90(2):331-338
Alumina supports with a very narrow pore size distribution were obtained with indium-doped alumina prepared by the sol-gel
method. The formation of aluminum in pentahedral coordination was identified by 27Al NMR-MAS-spectroscopy. A good correlation was obtained with the AlV NMR-MAS intensity signal and the activity in isopropanol dehydration. The insertion of In3+ substituting some Al3+ in the alumina network was suggested. 相似文献
13.
Hermogène Nsengimana Ewa M. Cukrowska Andrew Dinsmore Emmanuel Tessier David Amouroux 《Journal of separation science》2009,32(14):2426-2433
An analytical method for simultaneous in situ ethylation, of organolead, organotin and organomercury compounds in aqueous samples was developed using a new derivatisation agent, bromomagnesium tetraethylborate (BrMgEt4B). The determination of lead, tin and mercury compounds was done by species‐specific isotope dilution, derivatisation and GC–inductively coupled plasma MS (GC‐ICP‐MS) or by GC‐MS. The recovery and accuracy of the derivatisation were evaluated. The effect of pH and the relative quantity of derivatisation agent were studied. 相似文献
14.
Jeong SC Herrmann N Fan ZG Freifelder R Gobbi A Hildenbrand KD Krämer M Randrup J Reisdorf W Schüll D Sodan U Teh K Wessels JP Pelte D Trzaska M Wienold T Alard JP Amouroux V Basrak Z Bastid N Belayev IM Berger L Bini M Blaich T Boussange S Buta A Caplar R Cerruti C Cindro N Coffin JP Dona R Dupieux P Erö J Fintz P Fodor Z Fraysse L Frolov S Grigorian Y Guillaume G Hölbling S Houari A Jundt F Kecskemeti J Koncz P Korchagin Y Kotte R Kuhn C Ibnouzahir M Legrand I Lebedev A Maguire C Manko V 《Physical review letters》1994,72(22):3468-3471
15.
Noushine Shahidzadeh Mohamed M. Chehimi Farzaneh Arefi-Khonsari Jacques Amouroux Michel Delamar 《Plasmas and Polymers》1996,1(1):27-45
Acid-base properties of ammonia plasma-treated polypropylene (APTPP) were characterized by X-ray photoelectron spectroscopy
(XPS) in conjunction with the molecular probe technique and using chloroform (TCM) as a reference Lewis acid. It is shown
that TCM is retained by the basic surfaces of APTPP but not by the untreated PP. The retention of TCM is shown to be entirely
due to the formation of TCM:APTPP acid-base complexes. This is supported by the C12p3/2 binding energy (BE) and the shape of the Cl2p peak from the adsorbed TCM. ΔHAB, the heat of TCM:APTPP acid-base interaction was found to be in the range of 3.1–4.3 kcal/mol using a published Cl2p3/2 BE−ΔHAB correlation. This ΔHAB compares remarkably well with the values of 4.3–4.9 kcal/mol determined for TCM:amine complexes, and shows indeed that TCM
is complexed by nitrogen containing basic groups grafted at the surface. However, the TCM/N ratio has an optimal value up
to 1 second of plasma treatment and then decreases sharply, showing that less specific interaction sites are accessible at
the surface for longer treatment times. This parallels previous findings about the metallization of APTPP by aluminium which
was found to be optimal for treatment times lower than 1 second in our experimental conditions. This work shows that XPS can
now indeed be used to quantitatively assess the acid-base properties of modified polymer surfaces. 相似文献
16.
17.
The main methods of silicon purification involve physicochemical techniques of separation. They yield an ultrapure metal, but its price is not compatible with photovoltaic central power generation. The plasma zone melting process consists in the horizontal displacement of a melted zone under an argon-hydrogen-oxygen plasma. The melt zone is characterized by a vertical gradient of concentration and temperature which drains impurities toward the upper surface of the bar. Moreover, the displacement of the zone from the head to the tail of the bar ensures a horizontal drainage of impurities toward the tail. This technique has been used with success for purification of metallurgical grade silicon; for example, iron was reduced from 3500 ppm to 0.5 ppm at a displacement rate between 20 and 40 cm/h. The final impurity level was less than 1 ppm. The mass transfer was independent of the displacement rate at 40 cm/h, but dependent on the heat transfer rate. The segregation of the metals is caused by drainage toward the tail of the bar, while the plasma vaporizes impurities since the metallic and metalloidic impurities have high vapor pressures (e.g., S, P, C, O, Mn). Acid (HF-HNO3) is used to dissolve the impurities between each passage of the zone. Boron elimination depends directly on the plasma oxygen concentration. Classical mathematic models of zone melting are not valid for plasma melting zone processes. 相似文献
18.
19.
Zoyne Pedrero Zayas Laurent Ouerdane Sandra Mounicou Ryszard Lobinski Mathilde Monperrus David Amouroux 《Analytical and bioanalytical chemistry》2014,406(4):1121-1129
As methylmercury (MeHg) can be bioaccumulated and biomagnified in the trophic web, its toxicity for marine mammals is of major concern. Mercury speciation in marine biota has been widely studied, mainly focused on the discrimination and quantification of inorganic Hg and MeHg. Less attention has been paid to the interactions of Hg with biomolecules and the characterization of its specific binding, which play a key role in metabolic pathways controlling its uptake, transformation, and toxicity. In the studied white-sided dolphin (Lagenorhynchus acutus) liver homogenate (QC04LH4) sample, approximately 60 % of the total MeHg was found in the water soluble fraction, specifically associated with high molecular weight biomolecules. The identity of the involved proteins was investigated (after tryptic digestion of the fraction) by μRPLC with parallel detection by ICP-MS and ESI-MS/MS. Molecular mass spectrometry experiments were carried out at high resolution (100000) to ensure accurate protein identification and determination of the MeHg binding sites. Cysteine residue on the dolphin hemoglobin β chain was found to be the main MeHg binding site, suggesting that hemoglobin is a major MeHg binding protein in this marine mammal and could be a potential carrier of this MeHg from blood to liver prior to its degradation in this organ. In parallel, a significant proportion of selenium was found to be present as selenoneine and a potential role for this compound in Hg detoxification is discussed. 相似文献
20.
Me3SiCl/NaI in acetone opens regioselectively tetrahydrofurfurylalcohols and hydroxy-3 tetrahydrofuran to give the corresponding iodoacetonides in good yields. An application to the synthesis of the exo-and endo-brevicomins is described. 相似文献