Nanotubos de carbono no desenvolvimento de sensores eletroquímicos
Autor(a) principal: | |
---|---|
Data de Publicação: | 2010 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/6168 |
Resumo: | Carbon nanotubes (CNTs) have attracted great interest in electroanalysis. This material shows important properties as high charge transfer rate, high surface area and the presence of functional groups that make the sensors based on CNTs are attractive to be modified with several species. Metallic phthalocyanines (MPc) are well recognized for their excellent electrocatalytic properties and can be electrostatically adsorbed onto CNTs, where the CNT-MPc system shows a synergic and electrocatalytic effect. Thus, this work aims to characterize the electrocatalytic properties of CNTs, after a functionalization step of CNTs in an oxidizing media. Another objective is the development of electrochemical sensors based in functionalized CNTs modified with metallic phthalocyanines for the determination of environmental and medicinal substances. The CNTs were functionalized in oxidizing media (mixture 1:3 HNO3/H2SO4). The micro-structural analysis was characterized by FTIR and the FEGSEM and TEM microscopy, in which was observed that the functionalization step decreases the diameter of the tubes, unlocks the edge plans and increases the density of functional groups. The electrochemical characteristics of CNTs were examined by cyclic voltammetry and electrochemical impedance spectroscopy, in which these tests showed that the functionalized CNTs shift for more negative values the oxidation potential of redox couple [Fe(CN)6]4-/3-, as the electron transfer resistance, increase in oxidation and reduction current besides the improvement in the reversibility of the system. An electrochemical methodology were developed for the detection of pesticides 4-nitrophenol (4-NP), carbaryl, and glyphosate (Gly) in natural waters. For each pesticide used a specific sensor was constructed based on CNTs and metallic phthalocyanines. Medicinal substances (catecholamines) were also evaluated and developed sensors based on CNTs modified with cobalt phthalocyanine were developed. The proposed electrochemical sensors presented highly electrocatalytic and sensitive in the determination of pesticides and catecholamines. The proposed methodology were compared with the official methods of analysis and noted that the sensors yielded the detection limits required, demonstrating that electrochemical sensors based on CNTs become an alternative for the development of highly sensitive, rapid and low cost methodologies. |
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Moraes, Fernando Cruz deMascaro, Lucia Helenahttp://lattes.cnpq.br/9130022476352844http://lattes.cnpq.br/8597473049054728c178fde9-9e86-4b1d-9b32-4c1602765f662016-06-02T20:34:21Z2010-09-102016-06-02T20:34:21Z2010-08-27MORAES, Fernando Cruz de. Carbon nanotubes on development of electrochemical sensors. 2010. 144 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2010.https://repositorio.ufscar.br/handle/ufscar/6168Carbon nanotubes (CNTs) have attracted great interest in electroanalysis. This material shows important properties as high charge transfer rate, high surface area and the presence of functional groups that make the sensors based on CNTs are attractive to be modified with several species. Metallic phthalocyanines (MPc) are well recognized for their excellent electrocatalytic properties and can be electrostatically adsorbed onto CNTs, where the CNT-MPc system shows a synergic and electrocatalytic effect. Thus, this work aims to characterize the electrocatalytic properties of CNTs, after a functionalization step of CNTs in an oxidizing media. Another objective is the development of electrochemical sensors based in functionalized CNTs modified with metallic phthalocyanines for the determination of environmental and medicinal substances. The CNTs were functionalized in oxidizing media (mixture 1:3 HNO3/H2SO4). The micro-structural analysis was characterized by FTIR and the FEGSEM and TEM microscopy, in which was observed that the functionalization step decreases the diameter of the tubes, unlocks the edge plans and increases the density of functional groups. The electrochemical characteristics of CNTs were examined by cyclic voltammetry and electrochemical impedance spectroscopy, in which these tests showed that the functionalized CNTs shift for more negative values the oxidation potential of redox couple [Fe(CN)6]4-/3-, as the electron transfer resistance, increase in oxidation and reduction current besides the improvement in the reversibility of the system. An electrochemical methodology were developed for the detection of pesticides 4-nitrophenol (4-NP), carbaryl, and glyphosate (Gly) in natural waters. For each pesticide used a specific sensor was constructed based on CNTs and metallic phthalocyanines. Medicinal substances (catecholamines) were also evaluated and developed sensors based on CNTs modified with cobalt phthalocyanine were developed. The proposed electrochemical sensors presented highly electrocatalytic and sensitive in the determination of pesticides and catecholamines. The proposed methodology were compared with the official methods of analysis and noted that the sensors yielded the detection limits required, demonstrating that electrochemical sensors based on CNTs become an alternative for the development of highly sensitive, rapid and low cost methodologies.Os nanotubos de carbono (CNTs) têm despertado um grande interesse na área de eletroanálise, pois estes materiais possuem importantes características, como a alta velocidade na transferência de carga, alta área superficial e a presença de grupos funcionais que fazem com que os sensores baseados em CNTs sejam atrativos para serem modificados com diversos tipos de espécies. As ftalocianinas metálicas (MPc) são conhecidas como excelentes mediadores redox e podem ser eletrostaticamente adsorvidas sobres os CNTs, onde o sistema MPc-CNT apresenta efeito sinérgico e altamente eletrocatalítico. Desta forma, o objetivo deste trabalho é caracterizar as propriedades eletrocatalíticas dos CNTs, em relação à etapa de funcionalização destes em meio oxidante e desenvolver sensores eletroquímicos com CNTs modificados com MPc para a determinação de substâncias de interesse ambiental e medicinal. Os CNTs foram funcionalizados em meio oxidante (mistura 1:3 HNO3/H2SO4). A análise microestrutural foi antes e após a etapa de funcionalização foi realizada utilizando as técnicas de FTIR e as microscopias do tipo FEG-SEM e TEM, nas quais foram observados que a etapa de funcionalização diminui o diâmetro dos tubos, desbloqueia os planos de borda e aumenta a população de grupos funcionais. As características eletrocatalíticas dos CNTs foram analisadas pela voltametria cíclica e pela espectroscopia de impedância eletroquímica, nas quais estas análises demonstraram que os CNTs funcionalizados diminuíram tanto o potencial de oxidação do par redox [Fe(CN)6]4-/3-, quanto a resistência de transferência eletrônica, além de aumento nas correntes de oxidação e redução e melhoria na reversibilidade do sistema. Foram desenvolvidos métodos para a detecção dos defensivos agrícolas 4-nitrofenol (4-NP), carbaril e glifosato (Gli) em águas naturais. Para cada defensivo agrícola foi utilizado um sensor específico de CNTs e ftalocianinas metálicas. Substâncias medicinais (catecolaminas) também foram avaliadas e os sensores desenvolvidos foram baseados em CNTs modificados com ftalocianina de cobalto. Os sensores eletroquímicos propostos mostraram-se altamente eletrocatalíticos e sensíveis na determinação dos defensivos agrícolas das catecolaminas. A metodologia proposta comparada com os métodos oficiais de análise e foi observado que os sensores atingem os limites mínimos necessários de detecção, demonstrando que sensores eletroquímicos baseados em CNTs tornam-se uma alternativa no desenvolvimento de metodologias altamente sensíveis, rápidas e de baixo custo.Universidade Federal de Sao Carlosapplication/pdfporUniversidade Federal de São CarlosPrograma de Pós-Graduação em Química - PPGQUFSCarBRNanotubos de carbonoSensores eletroquímicosPesticidasCatecolaminasFtalocianina de cobaltoCIENCIAS EXATAS E DA TERRA::QUIMICANanotubos de carbono no desenvolvimento de sensores eletroquímicosCarbon nanotubes on development of electrochemical sensorsinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesis-1-148af9879-81a8-4651-b821-5243ab976eb2info:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINAL3202.pdfapplication/pdf2582388https://repositorio.ufscar.br/bitstream/ufscar/6168/1/3202.pdfa9947c2c189cf642579556cc508c9f1eMD51THUMBNAIL3202.pdf.jpg3202.pdf.jpgIM Thumbnailimage/jpeg8481https://repositorio.ufscar.br/bitstream/ufscar/6168/2/3202.pdf.jpg7fb809cc5d93e98efddb287903e041dcMD52ufscar/61682023-09-18 18:31:10.219oai:repositorio.ufscar.br:ufscar/6168Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:31:10Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Nanotubos de carbono no desenvolvimento de sensores eletroquímicos |
dc.title.alternative.eng.fl_str_mv |
Carbon nanotubes on development of electrochemical sensors |
title |
Nanotubos de carbono no desenvolvimento de sensores eletroquímicos |
spellingShingle |
Nanotubos de carbono no desenvolvimento de sensores eletroquímicos Moraes, Fernando Cruz de Nanotubos de carbono Sensores eletroquímicos Pesticidas Catecolaminas Ftalocianina de cobalto CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Nanotubos de carbono no desenvolvimento de sensores eletroquímicos |
title_full |
Nanotubos de carbono no desenvolvimento de sensores eletroquímicos |
title_fullStr |
Nanotubos de carbono no desenvolvimento de sensores eletroquímicos |
title_full_unstemmed |
Nanotubos de carbono no desenvolvimento de sensores eletroquímicos |
title_sort |
Nanotubos de carbono no desenvolvimento de sensores eletroquímicos |
author |
Moraes, Fernando Cruz de |
author_facet |
Moraes, Fernando Cruz de |
author_role |
author |
dc.contributor.authorlattes.por.fl_str_mv |
http://lattes.cnpq.br/8597473049054728 |
dc.contributor.author.fl_str_mv |
Moraes, Fernando Cruz de |
dc.contributor.advisor1.fl_str_mv |
Mascaro, Lucia Helena |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/9130022476352844 |
dc.contributor.authorID.fl_str_mv |
c178fde9-9e86-4b1d-9b32-4c1602765f66 |
contributor_str_mv |
Mascaro, Lucia Helena |
dc.subject.por.fl_str_mv |
Nanotubos de carbono Sensores eletroquímicos Pesticidas Catecolaminas Ftalocianina de cobalto |
topic |
Nanotubos de carbono Sensores eletroquímicos Pesticidas Catecolaminas Ftalocianina de cobalto CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
Carbon nanotubes (CNTs) have attracted great interest in electroanalysis. This material shows important properties as high charge transfer rate, high surface area and the presence of functional groups that make the sensors based on CNTs are attractive to be modified with several species. Metallic phthalocyanines (MPc) are well recognized for their excellent electrocatalytic properties and can be electrostatically adsorbed onto CNTs, where the CNT-MPc system shows a synergic and electrocatalytic effect. Thus, this work aims to characterize the electrocatalytic properties of CNTs, after a functionalization step of CNTs in an oxidizing media. Another objective is the development of electrochemical sensors based in functionalized CNTs modified with metallic phthalocyanines for the determination of environmental and medicinal substances. The CNTs were functionalized in oxidizing media (mixture 1:3 HNO3/H2SO4). The micro-structural analysis was characterized by FTIR and the FEGSEM and TEM microscopy, in which was observed that the functionalization step decreases the diameter of the tubes, unlocks the edge plans and increases the density of functional groups. The electrochemical characteristics of CNTs were examined by cyclic voltammetry and electrochemical impedance spectroscopy, in which these tests showed that the functionalized CNTs shift for more negative values the oxidation potential of redox couple [Fe(CN)6]4-/3-, as the electron transfer resistance, increase in oxidation and reduction current besides the improvement in the reversibility of the system. An electrochemical methodology were developed for the detection of pesticides 4-nitrophenol (4-NP), carbaryl, and glyphosate (Gly) in natural waters. For each pesticide used a specific sensor was constructed based on CNTs and metallic phthalocyanines. Medicinal substances (catecholamines) were also evaluated and developed sensors based on CNTs modified with cobalt phthalocyanine were developed. The proposed electrochemical sensors presented highly electrocatalytic and sensitive in the determination of pesticides and catecholamines. The proposed methodology were compared with the official methods of analysis and noted that the sensors yielded the detection limits required, demonstrating that electrochemical sensors based on CNTs become an alternative for the development of highly sensitive, rapid and low cost methodologies. |
publishDate |
2010 |
dc.date.available.fl_str_mv |
2010-09-10 2016-06-02T20:34:21Z |
dc.date.issued.fl_str_mv |
2010-08-27 |
dc.date.accessioned.fl_str_mv |
2016-06-02T20:34:21Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
MORAES, Fernando Cruz de. Carbon nanotubes on development of electrochemical sensors. 2010. 144 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2010. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/6168 |
identifier_str_mv |
MORAES, Fernando Cruz de. Carbon nanotubes on development of electrochemical sensors. 2010. 144 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2010. |
url |
https://repositorio.ufscar.br/handle/ufscar/6168 |
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por |
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por |
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48af9879-81a8-4651-b821-5243ab976eb2 |
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info:eu-repo/semantics/openAccess |
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openAccess |
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application/pdf |
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Universidade Federal de São Carlos |
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Programa de Pós-Graduação em Química - PPGQ |
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UFSCar |
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BR |
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Universidade Federal de São Carlos |
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