Amperometry
Mostrando 13-24 de 41 artigos, teses e dissertações.
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13. Desenvolvimento de metodologias analíticas usando FIA com detecção amperométrica : análise de dopamina, ácido ascórbico e ácido úrico
In the present work a simple, sensitive and selective method for determination of compounds of pharmaceutical and biological interest was investigated. The studies were addressed for analysis of the following analytes: (1) dopamine (DA) in the presence of high concentrations of ascorbic acid (AA); (2) dopamine in the presence of ascorbic and uric acid (UA) a
Publicado em: 2009
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14. Novos materiais para aplicações analíticas nas determinações de compostos orgânicos de interesse farmacêutico e ambiental / New materials for analytical application in organic compound determination for pharmaceutical and environmental interests
Carbon film sensors, built from resistors of 2 Ω nominal resistance, were employed for application in the environment and pharmaceutical fields without previous modification of the electrode surface. When these sensors are electrochemically treated they obtain a wider potential window (both anodic and cathodic regions) than many other forms of carbon. D
Publicado em: 2009
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15. Desenvolvimento de metodologias de análises em fluxo com detecção amperométrica de múltiplos pulsos
No presente trabalho investigou-se a potencialidade da detecção amperométrica de múltiplos pulsos (MPA) acoplada a sistemas em fluxo. Foram desenvolvidos métodoss de análises simples para a determinação simultânea de analitos de interesse farmacêutico ou ambiental usando a MPA acoplada a sistemas de análise por injeção em fluxo (FIA) e cromatogr
Publicado em: 2009
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16. Detecção amperométrica, com microeletrodos, de espécies reativas de oxigênio e nitrogênio em células isoladas estimuladas por substâncias biologicamente ativas. / Amperometric detection of reactive oxygen and nitrogen species in isolated cells, estimulated by biologically active organic compounds.
The production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) is a metabolic situation, observed in different physiological conditions. When their production is exacerbated, there is an efficient antioxidant system able to control and re-install the homeostasis. Oxidative stress results from an acute and chronic imbalance between the pr
Publicado em: 2008
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17. Filmes nanoestruturados de materiais de interesse biológico: ênfase na interação com modelos de membrana e aplicações em biossensores / Nanostructured films with materials of biological interest: emphasis on interaction with membrane models and biosensor applications
A imobilização de moléculas de interesse biológico em superfícies sólidas é essencial para uma série de aplicações biotecnológicas. Dentre as técnicas de imobilização, a automontagem camada por camada por adsorção física possui inúmeras vantagens, incluindo condições brandas e fisiológicas de preparação, capacidade de incorporar difere
Publicado em: 2008
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18. Instrumental innovations in capillary electrophoresis with electrochemical detection in the analysis of mono and oligosaccharides, amino acids and proteins / Inovações instrumentais em sistemas de eletroforese capilar com detecção eletroquímica e aplicações em análises de mono e oligossacarídeos, aminoácidos e proteínas
This work shows the development of two equipments (H1 and B1) of capillary electrophoresis (CE) with contactless conductivity detection (C4D) applied to the analysis of biomolecules. They have a system named MSE (module for separated electrolysis) that avoids the harmful effect of electrolysis. H1 have only one capillary and the majority of the experiments p
Publicado em: 2008
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19. Modified Electrodes with Tungsten Oxide: Preparation Methods and Analytic Applications / Eletrodos modificados por óxido de tungstênio: Métodos de preparação e aplicações analíticas
Thin films of non-stoichiometric tungsten oxides have been deposited onto glassy carbon surfaces by electrodeposition from acidic W (VI) solutions. At these modified surfaces, rotating disc electrode voltammetric experiments indicated that iodate is electrocatalytically reduced in a mass-transport controlled process. The influence of the film thickness on th
Publicado em: 2006
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20. Aplicações eletroanalíticas com eletrodos de prata confeccionados a partir de CDs graváveis
This paper presents a new way for the construction of silver electrodes utilizing recordable CDs. The new electrodes were explored for the quantification of chloride (by potentiometry/FIA), cyanide (by amperometry/FIA) and for lead analysis (by square wave voltammetry). For the flowing measurements, a digital multimeter, connected to a microcomputer (via RS
Química Nova. Publicado em: 2003-12
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21. Desenvolvimento de métodos analíticos em sistemas de soluções em fluxo empregando polifenol oxidase naturalmente imobilizada sobre tecidos vegetais / Development of analytical methodologies in flow injections systems employing polyphenoloxidase naturally immobilized on plant tissues
Esta tese apresenta o desenvolvimento de metodologias analíticas em sistemas de solução em fluxo com detecção amperométrica e espectrofotométrica explorando a utilização de tecidos vegetais como fonte enzimática para a biocatálise de reações. Desempenhos satisfatórios foram obtidos com a utilização do mesocarpo fibroso do coco (Cocus nucifera
Publicado em: 1998
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22. Estudo eletroquimico de corantes organicos com propriedades redox imobilizados sobre o fosfato de zirconio
Methylene Blue (MB) and Nile Blue (NB), a phenothiazine and a phenoxazine dyes respectively, were adsorbed on zirconium (IV) phosphate (ZP) by ion exchange reaction. The dyes were strongly retained and were not leached out from the matrix. The materials with adsorbed dyes (ZPMB e ZPNB) were incorporated into a carbon paste electrode and the electrochemical p
Publicado em: 1997
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23. Detection of exocytosis at individual pancreatic beta cells by amperometry at a chemically modified microelectrode.
Amperometry at a carbon fiber microelectrode modified with a composite of ruthenium oxide and cyanoruthenate was used to monitor chemical secretions of single pancreatic beta cells from rats and humans. When the insulin secretagogues glucose, tolbutamide, and K+ were applied to the cell, a series of randomly occurring current spikes was observed. The current
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24. Exocytotic release from individual granules exhibits similar properties at mast and chromaffin cells.
The effects of temperature on granular secretion were studied in individual bovine adrenal chromaffin and rat peritoneal mast cells. It was found that more molecules are released from individual granules at physiological temperature than at room temperature, where such experiments are normally performed. In mast cells, there is also a dramatic decrease in th