Ions Dissociation
Mostrando 1-12 de 149 artigos, teses e dissertações.
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1. SELECTIVE SEPARATION OF Mn(II) AND Cd(II) AS WELL AS REGENERATION OF POLYMER VIA SHEAR INDUCED DISSOCIATION COUPLING WITH ULTRAFILTRATION
Abstract The selective separation of Mn(II) and Cd(II) as well as regeneration of the complexing agent were conducted by shear induced dissociation coupling with ultrafiltration (SID-UF), and the copolymer of maleic acid and acrylic acid (PMA) was used as complexing agent. At the optimal complexation conditions, pH 6 and P/M (mass ratio of polymer to metal i
Braz. J. Chem. Eng.. Publicado em: 13/01/2020
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2. Determinação de designer drugs em saliva por paper spray mass spectrometry
Determination of two drugs of abuse in saliva has been performed by Paper Spray Ionization Mass Spectrometry (PSI-MS) using a Molecularly Imprinted Polymer (MIP) coated paper as substrate. The method has been optimized for quantification of 3,4-methylenedioxy- N-methylamphetamine (MDMA) and methamphetamine, 3,4-methylenedioxyamphetamine (MDA) from synthetic
Quím. Nova. Publicado em: 15/08/2019
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3. Fragmentation Reactions of Rhodamine B and 6G as Revealed by High Accuracy Orbitrap Tandem Mass Spectrometry
Correct interpretation of mass spectra is essential to our understanding of the ion chemistry occurring in the gas phase inside mass spectrometers and for constructing a solid knowledge from which mass spectrometry (MS) data of novel molecules will be interpreted. Assignments of product ions leading to incorrect dissociation mechanisms can also be dangerous
J. Braz. Chem. Soc.. Publicado em: 2017-01
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4. Atribuição absoluta e geral de isômeros constitucionais por espectrometria de massas: o caso das metilpiperidinas
An absolute method is described via mass spectrometry (MS) for the structural assignment of isomers within the class of methylpiperidines. The method explores both the unimolecular and bimolecular gas phase behavior of structurally diagnostic fragment ions (SDFI). For the methylpiperidnes, the isomeric 2-methyl, 3-methyl and 4-methyl 2-azabutadienyl cations
Química Nova. Publicado em: 2012
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5. Estudo qualitativo e quantitativo de biomarcadores ácidos e hidrocarbonetos presentes em óleos da Bacia Potiguar / Qualitative and quantitative study of acidic and hydrocarbon biomarkers of oil from the Potiguar Basin
rabalho foram sintetizados quatro biomarcadores ácidos, a saber: ácido 5b (H) colânico (2), 5a (H) homopregnânico (4), 8,13-tetraidrocopálico (6) e 15-isocopálico (7). Para tanto, foram utilizadas matérias primas comerciais (ácido litocólico e estigmasterol) e o ácido copálico (extraído e purificado a partir de bálsamo de copaíba). Também foi
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/12/2011
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6. Polimerização de estireno via radical livre mediada por nitroxidos usando iniciador trifuncional / Styrene polimerization via free radical mediated by nitroxides using trifunctional initiator
Controlled free radical polymerization, also known as "pseudo-living radical polymerization" or "Living Free Radical Polymerization" (LFRP) has received increasing attention as a technique for the production of polymers with micro structure highly controlled. In particular, narrow molecular weight distributions, are obtained with polidispersidade very close
Publicado em: 2009
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7. Estudo da desativação do agente VX usando o MgO por cálculos ab initio
The organophosphates are used in industry, in the fields of dyes, varnishes, artificial leather, electrical insulation, waterproofing, plastics, oil additives and solvents, are also used in medicine to treat diseases such as glaucoma, in the household and in agriculture are applied as insecticides and pesticides. Besides these various civilian facilities, th
Publicado em: 2009
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8. Extraction in chemistry: humic substances in soils and copper in cachaça / Estratégias de extração em química : substâncias húmicas em solos e cobre em cachaça
The goal of the extraction strategies here developed was to obtain final products with efficiency and reliability in a time interval as short as possible. The proposed methods are inexpensive and easily applied for different samples. The first extraction strategy proposed deals with humic substances, HS, removal in peat soils aiming the development of an ext
Publicado em: 2009
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9. The use of computational chemistry in the studies of chemical processes involved in electrospray ionization / A utilização da química computacional em processos químicos relacionados à ionização por electrospray
In recent decades, the development of atmospheric ionization techniques improved mass spectrometry, principally for characterization and structural elucidation of high-molecular weight compounds. The development of spray ionization was responsible for the spread of applications and studies of mass spectrometry, where the electrospray ionization is the most v
Publicado em: 2009
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10. Energética e mecanismos de processos iônicos em fase gasosa / Energetics and mechanisms of gas-phase ionic processes
The study of ionic reactivity in the gas-phase has been widely explored with mass spectrometry techniques. This thesis reports experimental and theoretical results in three different areas of gas-phase ion chemistry. The ionic processes were experimentally studied by Fourier transform mass spectrometry (FTMS or FT-ICR), a high resolution method that allows f
Publicado em: 2007
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11. Estudo voltamétrico da interação dos íons Zn2+, Cu2+, Cd2+ e Pb2+ com a enzima catalase
Catalase (CAT), which is an important enzyme that catalyzes the decomposition of hydrogen peroxide (H O ) to water (H O) and oxygen (O ), contains 2 2 2 2 some metal binding sites (Cys, His). The binding of metal ions to CAT can change or stabilize its secondary structure, resulting in its inhibition or activation, respectively. The inhibition of CAT, which
Publicado em: 2007
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12. Preparation, structural and electrochemical properties of V2O5-WO3 xerogel composite / Obtenção, caracterização e estudos das propriedades de compósitos formados por xerogéis de pentóxido de vanádio e óxido de tungstênio
Vanadium pentoxide xerogel has a bi-dimensional structure which is suitable for intercalation of a variety of ions, organic compounds, and even polymeric species. In addition, when associated with other metal oxides such as WO3 and MoO3, it presents an important role in catalysis, since the resulting oxides act as promoters in catalytic reduction of the NOx
Publicado em: 2007