Determinação de tiocompostos por voltametria e coulometria em matrizes salinas
Ano de defesa: | 2006 |
---|---|
Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | , , , |
Tipo de documento: | Tese |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Universidade Federal de Santa Maria
|
Programa de Pós-Graduação: |
Programa de Pós-Graduação em Química
|
Departamento: |
Química
|
País: |
BR
|
Palavras-chave em Português: | |
Área do conhecimento CNPq: | |
Link de acesso: | http://repositorio.ufsm.br/handle/1/4297 |
Resumo: | The Laboratory of Support to Hemodialysis Clinics (LACHEM) has been investigating for many years the behaviour of many species in saline matrices as hemodialysis salts. In this work, the determination of the five thiocompounds related to agricultural defensives was investigated through electrochemical techniques in saline medium, based on the ionic forces present in saline concentrates used in Hemodialysis also in the sea water. The thiocompounds studied were thiotriazines ametryn, desmetryn, prometryn and terbutryn, which belong to the class of herbicides and the Ethylenethiourea (ETU), which is a degradation product in the class of Ethylenebisdithiocarbamate (EBDC). The high persistence of the triazines in the environment and the high levels of EBDC degradation products applied in crops as defensives, were the principal reason why these species were chosen. Moreover, another important reason is the fact the Brazilian legislation still do not requires the control of agrochemicals for fluids used in hemodialysis, perhaps for the small number of methodologies existent for this case. The electrochemical behaviour of these species was investigated by Voltammetry, Amperometry and Coulometry in aqueous samples of different ionic strenght. The preconcentration of analytes in columns and the diffusion through of the membranes of Teflon simulating the hemodialysis process were also investigated in this work. Constant-potential coulometry was used to compare the electrochemical behaviour of agrochemicals in relation to carbon vitreous reticulated (CVR) electrodes with Hg electrodeposition as well as with copper electrode after Hg electrodeposition, in an off line system. In an on line system, an electrochemical cell was built to determine these species by using a copper wire with Hg electrodeposited as a working electrode. The analytes preconcentration in columns of polystyrene (PS) was an alternative for the determination of the agrochemicals by coulometry, considering that through this technique was only possible to detect concentrations in levels of the mg L-1 of ETU and thiotriazines, utilizing mercury electrodes built with large superficial areas which produce the best results in electrolysis. In this work, electrolysis results lower than 100% were adopted to reduce the analysis time. For the amperometrics measure, an on-line system with CVR electrode was investigated in the determination of triazines. This system allowed the analysis with a high sensibility and fast. Analytical curves with concentrations from 1 μg L-1 were gotten using this system. In measures by Voltammetry were utilized Hg electrodes (HMDE) and Au to determine triazines and ETU in concentrations from 2 μg L-1. In this work, the ETU diffusion as also investigated through Teflon membranes, simulating the hemodialysis process. In this process, the diffusion cell is divided in two parts, the flow and the counterflow paths, where circulate the donor solution (saline solutions with different ionic strenght) and the adsorbent solution. The aim of this work was to evaluate the influence of saline medium in the diffusion of those species through the Teflon membrane. In the process of hemodialysis, the membranes utilized presented a bigger permeability than the Teflon s, in a way that this material was chosen as an indicator in a limit situation. The saline medium was responsible for increments of 1,5 to 2,5% in the analyte diffusion through of Teflon, in relation to pure water. However, significative differences in the diffusion taxes for saline medium with the ionic strenght investigated (corresponding to the hemodialysis fluids and sea water) were not observed. This work discusses the results obtained in electrochemical systems, comparing the analytes determinations to different electrodes utilized in aqueous and saline samples with different ionic strenght. |
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2017-05-182017-05-182006-08-11TREVISAN, Joselito. Determination of thiocompounds by voltammetry and coulometry in saline matrices. 2006. 176 f. Tese (Doutorado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2006.http://repositorio.ufsm.br/handle/1/4297The Laboratory of Support to Hemodialysis Clinics (LACHEM) has been investigating for many years the behaviour of many species in saline matrices as hemodialysis salts. In this work, the determination of the five thiocompounds related to agricultural defensives was investigated through electrochemical techniques in saline medium, based on the ionic forces present in saline concentrates used in Hemodialysis also in the sea water. The thiocompounds studied were thiotriazines ametryn, desmetryn, prometryn and terbutryn, which belong to the class of herbicides and the Ethylenethiourea (ETU), which is a degradation product in the class of Ethylenebisdithiocarbamate (EBDC). The high persistence of the triazines in the environment and the high levels of EBDC degradation products applied in crops as defensives, were the principal reason why these species were chosen. Moreover, another important reason is the fact the Brazilian legislation still do not requires the control of agrochemicals for fluids used in hemodialysis, perhaps for the small number of methodologies existent for this case. The electrochemical behaviour of these species was investigated by Voltammetry, Amperometry and Coulometry in aqueous samples of different ionic strenght. The preconcentration of analytes in columns and the diffusion through of the membranes of Teflon simulating the hemodialysis process were also investigated in this work. Constant-potential coulometry was used to compare the electrochemical behaviour of agrochemicals in relation to carbon vitreous reticulated (CVR) electrodes with Hg electrodeposition as well as with copper electrode after Hg electrodeposition, in an off line system. In an on line system, an electrochemical cell was built to determine these species by using a copper wire with Hg electrodeposited as a working electrode. The analytes preconcentration in columns of polystyrene (PS) was an alternative for the determination of the agrochemicals by coulometry, considering that through this technique was only possible to detect concentrations in levels of the mg L-1 of ETU and thiotriazines, utilizing mercury electrodes built with large superficial areas which produce the best results in electrolysis. In this work, electrolysis results lower than 100% were adopted to reduce the analysis time. For the amperometrics measure, an on-line system with CVR electrode was investigated in the determination of triazines. This system allowed the analysis with a high sensibility and fast. Analytical curves with concentrations from 1 μg L-1 were gotten using this system. In measures by Voltammetry were utilized Hg electrodes (HMDE) and Au to determine triazines and ETU in concentrations from 2 μg L-1. In this work, the ETU diffusion as also investigated through Teflon membranes, simulating the hemodialysis process. In this process, the diffusion cell is divided in two parts, the flow and the counterflow paths, where circulate the donor solution (saline solutions with different ionic strenght) and the adsorbent solution. The aim of this work was to evaluate the influence of saline medium in the diffusion of those species through the Teflon membrane. In the process of hemodialysis, the membranes utilized presented a bigger permeability than the Teflon s, in a way that this material was chosen as an indicator in a limit situation. The saline medium was responsible for increments of 1,5 to 2,5% in the analyte diffusion through of Teflon, in relation to pure water. However, significative differences in the diffusion taxes for saline medium with the ionic strenght investigated (corresponding to the hemodialysis fluids and sea water) were not observed. This work discusses the results obtained in electrochemical systems, comparing the analytes determinations to different electrodes utilized in aqueous and saline samples with different ionic strenght.O Laboratório de Apoio a Clínicas de Hemodiálise LACHEM vem há anos investigando o comportamento de várias espécies em matrizes salinas como os sais para hemodiálise. No presente trabalho, a determinação de cinco tiocompostos relacionados à defensivos agrícolas foi investigada através de métodos eletroanalíticos em meios salinos, tomando-se por base as forças iônicas presentes nos concentrados salinos utilizados em hemodiálise e água do mar. Os tiocompostos estudados foram as tiotriazinas ametrina, desmetrina, prometrina e terbutrina que pertencem a uma classe de herbicidas e a ETU (Etilenotiourea) que é um produto de degradação da classe dos EBDCs (Etilenobisditiocarbamatos). A alta persistência das tiotriazinas no meio ambiente e os altos índices de produtos de degradação dos EBDCs que são aplicados nas lavouras como defensivos agrícolas, foram as principais razões para escolha destas espécies. Além disso, outra razão muito importante é o fato da legislação brasileira ainda não exigir o controle de agroquímicos para os fluidos utilizados em hemodiálise, talvez pelo pequeno número de metodologias para esse fim. O comportamento eletroquímico destas espécies foi investigado através da Voltametria, Amperometria e Coulometria em amostras aquosas de diferentes forças iônicas. A pré-concentração dos analitos em colunas e a difusão através de membranas de teflon simulando o processo de hemodiálise foram também investigadas neste trabalho. Com a Coulometria de potencial constante comparou-se o comportamento eletroquímico dos agroquímicos em relação a eletrodos de carbono vítreo reticulado (CVR) com eletrodeposição de Hg e com eletrodo de cobre após eletrodeposição de Hg, em um sistema off line. Em sistema on line, uma célula eletroquímica foi construída para a determinação das espécies utilizando como eletrodo de trabalho um fio de cobre com Hg eletrodepositado. A pré-concentração dos analitos em colunas de Poliestireno (PS) foi uma alternativa para determinar os agroquímicos por Coulometria, considerando que através desta técnica somente foi possível detectar concentrações na faixa de mg L-1 de ETU e tiotriazinas utilizando eletrodos de mercúrio construídos com grandes áreas superficiais que produzem melhores rendimentos na eletrólise. Neste trabalho rendimentos de eletrólise inferiores a 100% foram adotados visando diminuir o tempo de análise. Para medidas amperométricas, investigou-se um sistema on line com eletrodo de CVR na determinação de tiotriazinas. Este sistema de detecção permitiu análises com alta sensibilidade e rapidez. Curvas analíticas com concentrações a partir de 1 μg L-1 foram obtidas utilizando este sistema. Em medidas por voltametria foram utilizados eletrodos de Hg (HMDE) e Au para a determinação de tiotriazinas e ETU em concentrações a partir de 2 μg L-1. Neste trabalho, também foi investigada a difusão de ETU através de membranas de teflon, simulando o processo de hemodiálise, onde a célula de difusão é dividida em duas partes, o caminho de fluxo e do contra fluxo por onde circulam as soluções doadoras (soluções salinas com diferentes forças iônicas) e a solução absorvente. O objetivo deste estudo foi avaliar a influência do meio salino na difusão das espécies através da membrana de teflon. No processo de hemodiálise, as membranas utilizadas apresentam permeabilidade muito maior do que o teflon de modo que este material foi escolhido como indicador de uma situação limite. O meio salino foi responsável por incrementos na difusão do analito através do teflon de 1,5% a 2,5% em relação à água pura. Contudo, diferenças significativas nas taxas de difusão para meios salinos com as forças iônicas investigadas (correspondentes aos fluidos de hemodiálise e água do mar) não foram observadas. O presente trabalho discute os resultados obtidos nos sistemas eletroquímicos, comparando as determinações dos analitos com os diferentes eletrodos utilizados em amostras aquosas e salinas com diferentes forças iônicas.Coordenação de Aperfeiçoamento de Pessoal de Nível Superiorapplication/pdfporUniversidade Federal de Santa MariaPrograma de Pós-Graduação em QuímicaUFSMBRQuímicaQuímicaQuímica analíticaHerbicidasVoltametriaCoulometriaCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICADeterminação de tiocompostos por voltametria e coulometria em matrizes salinasDetermination of thiocompounds by voltammetry and coulometry in saline matricesinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisNascimento, Paulo Cícero dohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788664D2Goncalves, Reinaldo Simoeshttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783174Y3Spinelli, Almirhttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4781759Y0Carvalho, Leandro Machado dehttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4795379U4Garcia, Solange Cristinahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4790220Y7http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4701346A4Trevisan, Joselito1006000000004003003003003003005002042fb16-c273-4428-8d59-fe233e346cbb1290e163-e44f-467d-9c58-24a57f6043e560f6767c-1b84-42ea-8dac-e79011d4e19567b1ea0d-636f-4313-9491-f02d02934bfbf2f2e781-e9c2-4ccc-9eae-d75551934971fb539601-2fef-4de4-8a6d-8230b0e3d721info:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSMORIGINALJOSELITOTREVISAN.pdfTese de Doutoradoapplication/pdf1043677http://repositorio.ufsm.br/bitstream/1/4297/1/JOSELITOTREVISAN.pdfbc02f597a640261b4641bed3001b0708MD51TEXTJOSELITOTREVISAN.pdf.txtJOSELITOTREVISAN.pdf.txtExtracted texttext/plain271241http://repositorio.ufsm.br/bitstream/1/4297/2/JOSELITOTREVISAN.pdf.txt46b6050cfcca0c9817a2589efbc88d0fMD52THUMBNAILJOSELITOTREVISAN.pdf.jpgJOSELITOTREVISAN.pdf.jpgIM Thumbnailimage/jpeg4843http://repositorio.ufsm.br/bitstream/1/4297/3/JOSELITOTREVISAN.pdf.jpgf445b974b7ef48c779fa68adacde915fMD531/42972018-01-26 02:29:12.721oai:repositorio.ufsm.br:1/4297Repositório Institucionalhttp://repositorio.ufsm.br/PUBhttp://repositorio.ufsm.br/oai/requestopendoar:39132018-01-26T04:29:12Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false |
dc.title.por.fl_str_mv |
Determinação de tiocompostos por voltametria e coulometria em matrizes salinas |
dc.title.alternative.eng.fl_str_mv |
Determination of thiocompounds by voltammetry and coulometry in saline matrices |
title |
Determinação de tiocompostos por voltametria e coulometria em matrizes salinas |
spellingShingle |
Determinação de tiocompostos por voltametria e coulometria em matrizes salinas Trevisan, Joselito Química Química analítica Herbicidas Voltametria Coulometria CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Determinação de tiocompostos por voltametria e coulometria em matrizes salinas |
title_full |
Determinação de tiocompostos por voltametria e coulometria em matrizes salinas |
title_fullStr |
Determinação de tiocompostos por voltametria e coulometria em matrizes salinas |
title_full_unstemmed |
Determinação de tiocompostos por voltametria e coulometria em matrizes salinas |
title_sort |
Determinação de tiocompostos por voltametria e coulometria em matrizes salinas |
author |
Trevisan, Joselito |
author_facet |
Trevisan, Joselito |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
Nascimento, Paulo Cícero do |
dc.contributor.advisor1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788664D2 |
dc.contributor.referee1.fl_str_mv |
Goncalves, Reinaldo Simoes |
dc.contributor.referee1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783174Y3 |
dc.contributor.referee2.fl_str_mv |
Spinelli, Almir |
dc.contributor.referee2Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4781759Y0 |
dc.contributor.referee3.fl_str_mv |
Carvalho, Leandro Machado de |
dc.contributor.referee3Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4795379U4 |
dc.contributor.referee4.fl_str_mv |
Garcia, Solange Cristina |
dc.contributor.referee4Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4790220Y7 |
dc.contributor.authorLattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4701346A4 |
dc.contributor.author.fl_str_mv |
Trevisan, Joselito |
contributor_str_mv |
Nascimento, Paulo Cícero do Goncalves, Reinaldo Simoes Spinelli, Almir Carvalho, Leandro Machado de Garcia, Solange Cristina |
dc.subject.por.fl_str_mv |
Química Química analítica Herbicidas Voltametria Coulometria |
topic |
Química Química analítica Herbicidas Voltametria Coulometria CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.cnpq.fl_str_mv |
CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
The Laboratory of Support to Hemodialysis Clinics (LACHEM) has been investigating for many years the behaviour of many species in saline matrices as hemodialysis salts. In this work, the determination of the five thiocompounds related to agricultural defensives was investigated through electrochemical techniques in saline medium, based on the ionic forces present in saline concentrates used in Hemodialysis also in the sea water. The thiocompounds studied were thiotriazines ametryn, desmetryn, prometryn and terbutryn, which belong to the class of herbicides and the Ethylenethiourea (ETU), which is a degradation product in the class of Ethylenebisdithiocarbamate (EBDC). The high persistence of the triazines in the environment and the high levels of EBDC degradation products applied in crops as defensives, were the principal reason why these species were chosen. Moreover, another important reason is the fact the Brazilian legislation still do not requires the control of agrochemicals for fluids used in hemodialysis, perhaps for the small number of methodologies existent for this case. The electrochemical behaviour of these species was investigated by Voltammetry, Amperometry and Coulometry in aqueous samples of different ionic strenght. The preconcentration of analytes in columns and the diffusion through of the membranes of Teflon simulating the hemodialysis process were also investigated in this work. Constant-potential coulometry was used to compare the electrochemical behaviour of agrochemicals in relation to carbon vitreous reticulated (CVR) electrodes with Hg electrodeposition as well as with copper electrode after Hg electrodeposition, in an off line system. In an on line system, an electrochemical cell was built to determine these species by using a copper wire with Hg electrodeposited as a working electrode. The analytes preconcentration in columns of polystyrene (PS) was an alternative for the determination of the agrochemicals by coulometry, considering that through this technique was only possible to detect concentrations in levels of the mg L-1 of ETU and thiotriazines, utilizing mercury electrodes built with large superficial areas which produce the best results in electrolysis. In this work, electrolysis results lower than 100% were adopted to reduce the analysis time. For the amperometrics measure, an on-line system with CVR electrode was investigated in the determination of triazines. This system allowed the analysis with a high sensibility and fast. Analytical curves with concentrations from 1 μg L-1 were gotten using this system. In measures by Voltammetry were utilized Hg electrodes (HMDE) and Au to determine triazines and ETU in concentrations from 2 μg L-1. In this work, the ETU diffusion as also investigated through Teflon membranes, simulating the hemodialysis process. In this process, the diffusion cell is divided in two parts, the flow and the counterflow paths, where circulate the donor solution (saline solutions with different ionic strenght) and the adsorbent solution. The aim of this work was to evaluate the influence of saline medium in the diffusion of those species through the Teflon membrane. In the process of hemodialysis, the membranes utilized presented a bigger permeability than the Teflon s, in a way that this material was chosen as an indicator in a limit situation. The saline medium was responsible for increments of 1,5 to 2,5% in the analyte diffusion through of Teflon, in relation to pure water. However, significative differences in the diffusion taxes for saline medium with the ionic strenght investigated (corresponding to the hemodialysis fluids and sea water) were not observed. This work discusses the results obtained in electrochemical systems, comparing the analytes determinations to different electrodes utilized in aqueous and saline samples with different ionic strenght. |
publishDate |
2006 |
dc.date.issued.fl_str_mv |
2006-08-11 |
dc.date.accessioned.fl_str_mv |
2017-05-18 |
dc.date.available.fl_str_mv |
2017-05-18 |
dc.type.status.fl_str_mv |
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info:eu-repo/semantics/doctoralThesis |
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publishedVersion |
dc.identifier.citation.fl_str_mv |
TREVISAN, Joselito. Determination of thiocompounds by voltammetry and coulometry in saline matrices. 2006. 176 f. Tese (Doutorado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2006. |
dc.identifier.uri.fl_str_mv |
http://repositorio.ufsm.br/handle/1/4297 |
identifier_str_mv |
TREVISAN, Joselito. Determination of thiocompounds by voltammetry and coulometry in saline matrices. 2006. 176 f. Tese (Doutorado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2006. |
url |
http://repositorio.ufsm.br/handle/1/4297 |
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