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Previous issue date: 2013 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / Neste trabalho,foi desenvolvido umbiossensor amperom?trico altamente sens?vel baseado na inibi??o da acetilcolinesterase (AChE).O m?todobaseia-se num eletrodo de pasta de nanotubos modificado com aftalocianina tetrassulfonada decobaltoe o l?quido i?nico tetrafluoroborato de 1-metil-3-octilimidaz?lio.Imagensde Microscopia Eletr?nica de Varredurae Espectroscopia de Infravermelho por Transformada de Fourierforam utilizadas para caracterizaros materiais.O processo de oxida??o datiocolinafoi investigadopor voltametria c?clica(CV) ecronoamperometria. A enzimaAChfoi imobilizadana superf?cie doeletrodo do comp?sitopor liga??o cruzadacomglutaralde?do equitosana.A a??osin?rgica do biossensorNTCPM/CoTSPc/AchEmostrou excelenteatividade eletrocatal?ticacombaixopotencial aplicadopara a detec??o detiocolina. Par?metrosque afetama resposta dobiossensor, como quantidadede enzima, tempo de incuba??o, pHe a concentra??oda solu??o tamp?oforam otimizadosutilizandocloreto deacetiltiocolina(ATCl) como substrato. Os resultadosmostraram que ofenitrotion, diclorvos e malationpodem levar aoprocesso de inibi??orevers?velda enzima.Estebiossensorapresentou um baixo limite dedetec??o, boa reprodutibilidade, elevada estabilidade sendo usadopara determinarpesticidas emamostras de ?gua. Rela??es linearesforam encontradasparafenitrotion(1,0-1000,0 pmolL-1), diclorvos(2,0-8.000,0 pmolL-1)emalation(16,0-5000,0 pmolL-1).O biossensor foi aplicado com sucesso em amostras de ?gua de rio e os resultados mostraram que o mesmo n?o sofre interfer?ncia da matriz biol?gica. Estudos de adi??o e recupera??o dos analitos foram realizados para avaliar a exatid?o do m?todo obtendo-se uma porcentagem de recupera??o entre 99,12% e 103,05% para o fenitrotion, 94,12% e 102,17% para o diclorvos e 100,03% e 100,96% para o malation. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2013. / ABSTRACT
In this work, a highly sensitive acetylcholinesterase (AChE) inhibition-based amperometric biosensor has been developed. The method is based on a cobalt phthalocyanine tetrasulfonate and 1-methyl-3-octylimidazolium tetrafluoroborate ionic liquidmodified nanotubes paste electrode. Images Scanning Electron Microscopy and Spectroscopy Fourier Transform Infrared were used to characterize the materials. The thiocholine oxidation process was investigated by cyclic voltammetry (CV) and chronoamperometry. The AChE enzyme was immobilized on the composite electrode surface by cross-linking with glutaraldehyde and chitosan. The synergistic action of NTCPM/CoTSPc/AChE showed excellent electrocatalytic activity with low applied potential for the detection of thiocholine. Parameters affecting the biosensor response such as enzyme loading, incubation time, pH and concentration of the buffer solution were optimized utilizing acetylthiocholine chloride (ATChCl) as substrate. The results showed that the fenitrothion, dichlorvos and malathion can lead to a reversible inhibition process of the enzyme. This biosensor showed low detection limit, good reproducibility, high stability and was used to determine pesticides in water samples. Linear relationships were found for fenitrothion (1.0-1000.0 pmol L-1), dichlorvos (2.0-8000.0 pmol L-1) and malathion (16.0-5000.0 pmol L-1. The biosensor has been successfully applied for river water samples and the results showed that there is no interference from the biological matrix. Recovery studies were performed to evaluate the accuracy of the method yielding a percentage of recovery between 99.12% and 103.05% for fenitrothion, 94.12% and 102.17% for dichlorvos and 100 03% and 100.96% for malathion.
| Identifer | oai:union.ndltd.org:IBICT/oai:acervo.ufvjm.edu.br/jspui:1/293 |
| Date | January 2013 |
| Creators | Pereira, Neuma das Merc?s |
| Contributors | Mu?os, Rodrigo Alejandro Abarza, Ferreira, Lucas Franco, Damos, Flavio Santos, Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Luz, Rita de C?ssia Silva |
| Publisher | UFVJM |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFVJM, instname:Universidade Federal dos Vales do Jequitinhonha e Mucuri, instacron:UFVJM |
| Rights | A concess?o da licen?a deste item refere-se ao ? termo de autoriza??o impresso assinado pelo autor, assim como na licen?a Creative Commons, com as seguintes condi??es: Na qualidade de titular dos direitos de autor da publica??o, autorizo a Universidade Federal dos Vales do Jequitinhonha e Mucuri e o IBICT a disponibilizar por meio de seus reposit?rios, sem ressarcimento dos direitos autorais, de acordo com a Lei n? 9610/98, o texto integral da obra disponibilizada, conforme permiss?es assinaladas, para fins de leitura, impress?o e/ou download, a t?tulo de divulga??o da produ??o cient?fica brasileira, e preserva??o, a partir desta data., info:eu-repo/semantics/openAccess |
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