Estudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatos
Ano de defesa: | 2005 |
---|---|
Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | , |
Tipo de documento: | Dissertação |
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/1/10400 |
Resumo: | Lead determination by graphite furnace atomic absorption spectrometry may be affected by some interferences. Several authors have reported that lead determination may be affected in the presence of some salts (carbonates chloride, nitrate and sulphate). Sulphates have been highlighted as potential interferents in lead determination. Interferences as analytical signal suppression and high background signal may be observed, even at low sulphate concentration. The main goal of this work was to verify the interferences caused during lead atomization in the presence of CaSO4, Na2SO4, FeSO4 e (NH4)2SO4, and try to minimize the interferences using chemical modifiers. This work was developed using a lead reference solution (10 μgl-1). This solution was placed into graphite furnace (10 μl), an amount corresponding to 100 pg lead, in the presence of different amounts of sulphate. It was observed signal suppression and high background signals. However, interferences caused by Na2SO4, FeSO4 e (NH4)2SO4 were minimized by optimization of pyrolysis and atomization temperatures. On the other hand, interferences caused by CaSO4 (27 μg) produced suppression in the analytical signal (66%), and they were just corrected by the use of chemical modifiers. This suppression effect was corrected using 3 μg Pd, and background signal was negligible in the presence of 5 μg Pd. It was verified that organic modifiers (ascorbic, oxalic and citric acid) were also efficient as chemical modifiers to correct the interferences observed in the presence of this salt. At optimized conditions in the presence of CaSO4, lead was determined in plaster samples (CaSO4.2H2O). The lead amount in these samples was smaller than the limit of detection. It was necessary the use of spiked samples to verify the performance of the developed method. Analyte recovery in the presence of ascorbic acid at the optimized pyrolysis and atomization temperatures was close to 100%. In this way, the use of organic chemical modifiers, as ascorbic acid, may be considered a reliable an relatively inexpensive procedure (when compared to the use of Pd) for the minimization of the interferences caused by calcium sulfate for lead determination by GF AAS. |
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2008-02-202008-02-202005-03-03NUNES, Adriane Medeiros. Study of the influence of chemical modifiers in lead determination by GF AAS in the presence of sulphates. 2005. 104 f. Dissertação (Mestrado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2005.http://repositorio.ufsm.br/handle/1/10400Lead determination by graphite furnace atomic absorption spectrometry may be affected by some interferences. Several authors have reported that lead determination may be affected in the presence of some salts (carbonates chloride, nitrate and sulphate). Sulphates have been highlighted as potential interferents in lead determination. Interferences as analytical signal suppression and high background signal may be observed, even at low sulphate concentration. The main goal of this work was to verify the interferences caused during lead atomization in the presence of CaSO4, Na2SO4, FeSO4 e (NH4)2SO4, and try to minimize the interferences using chemical modifiers. This work was developed using a lead reference solution (10 μgl-1). This solution was placed into graphite furnace (10 μl), an amount corresponding to 100 pg lead, in the presence of different amounts of sulphate. It was observed signal suppression and high background signals. However, interferences caused by Na2SO4, FeSO4 e (NH4)2SO4 were minimized by optimization of pyrolysis and atomization temperatures. On the other hand, interferences caused by CaSO4 (27 μg) produced suppression in the analytical signal (66%), and they were just corrected by the use of chemical modifiers. This suppression effect was corrected using 3 μg Pd, and background signal was negligible in the presence of 5 μg Pd. It was verified that organic modifiers (ascorbic, oxalic and citric acid) were also efficient as chemical modifiers to correct the interferences observed in the presence of this salt. At optimized conditions in the presence of CaSO4, lead was determined in plaster samples (CaSO4.2H2O). The lead amount in these samples was smaller than the limit of detection. It was necessary the use of spiked samples to verify the performance of the developed method. Analyte recovery in the presence of ascorbic acid at the optimized pyrolysis and atomization temperatures was close to 100%. In this way, the use of organic chemical modifiers, as ascorbic acid, may be considered a reliable an relatively inexpensive procedure (when compared to the use of Pd) for the minimization of the interferences caused by calcium sulfate for lead determination by GF AAS.A determinação de chumbo por espectrometria de absorção atômica com forno de grafite pode estar sujeita a algumas interferências. Vários autores têm relatado que na presença de alguns sais (carbonatos, cloretos, nitratos e sulfatos) o processo de determinação do Pb pode ser prejudicado. Sais de sulfato tem se destacado como potencias interferentes na determinação deste elemento pois, mesmo em baixas concentrações, interferências como supressão do sinal analítico e intenso sinal de fundo podem ser observadas. Desta forma, este trabalho teve como objetivo principal, verificar as interferências na determinação do Pb na presença de alguns sulfatos (CaSO4, Na2SO4, FeSO4 e (NH4)2SO4), bem como tentar minimizar as interferências observadas através do uso de modificadores químicos. O estudo foi desenvolvido empregando uma solução de referência de Pb de 10 μg l-1 como amostra teste. Foi adicionado no forno de grafite o correspondente a 100 pg deste elemento na presença de diferentes quantidades dos respectivos sais de sulfatos. Observou-se que a atomização do Pb sofre interferências como supressão do sinal analítico e um intenso sinal de fundo na presença destes sais, mas as interferências verificadas na presença de Na2SO4, FeSO4 e (NH4)2SO4 puderam ser corrigidas através da otimização das temperaturas de pirólise e atomização. As interferências causadas por CaSO4 (27 μg) resultaram em uma supressão de 66% do sinal analítico do Pb e somente foram corrigidas através do uso de modificadores químicos. A supressão do sinal analítico do Pb na presença deste sal, foi corrigida na presença de 3 μg de Pd e o sinal de fundo é praticamente desprezível com o uso de 5 μg deste modificador. Verificou-se que modificadores orgânicos (ácido ascórbico, ácido cítrico e ácido oxálico) também foram eficientes para a correção das interferências observadas na presença deste sal. Depois de definidas as melhores condições para a determinação de Pb na presença do CaSO4, foi feita a determinação em amostras de gesso (CaSO4. 2 H2O). Como a concentração de Pb nestas amostras foi abaixo do limite de detecção da técnica utilizada, foram realizados testes de recuperação de analito para verificar o desempenho do método desenvolvido. A recuperação usando ácido ascórbico como modificador químico, nas melhores temperaturas de pirólise e atomização, foi próximo a 100%. Desta forma o uso de modificadores químicos orgânicos, pode ser uma alternativa viável e barata (comparando-se ao Pd, por exemplo) para resolução das interferências causadas por sulfato de cálcio na determinação de chumbo por GF AAS.Coordenação de Aperfeiçoamento de Pessoal de Nível Superiorapplication/pdfporUniversidade Federal de Santa MariaPrograma de Pós-Graduação em QuímicaUFSMBRQuímicaQuímicaQuimica analíticaChumboCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICAEstudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatosStudy of the influence of chemical modifiers in lead determination by GF AAS in the presence of sulphatesinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisFlores, Érico Marlon de Moraeshttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782125T8Mortari, Sergio Robertohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4721640J6Pozebon, Dircehttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792312U6http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4735597D6Nunes, Adriane Medeiros100600000000400500500500500a9c2788c-7913-4d7b-92e1-3429800ac02817148421-12ec-4640-b1be-5d5689c5732fb4d0ba10-19c4-43bb-8e88-bb2ae6aa3e1bebaacc9b-884b-4f52-8867-e201fb0187f7info:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSMORIGINALADRIANE NUNES.pdfapplication/pdf825801http://repositorio.ufsm.br/bitstream/1/10400/1/ADRIANE%20NUNES.pdf01614a3bf2c2c69165c352d37b97ec30MD51TEXTADRIANE NUNES.pdf.txtADRIANE NUNES.pdf.txtExtracted texttext/plain161744http://repositorio.ufsm.br/bitstream/1/10400/2/ADRIANE%20NUNES.pdf.txtfa48ce7484c64693ebc41cb0ae94e955MD52THUMBNAILADRIANE NUNES.pdf.jpgADRIANE NUNES.pdf.jpgIM Thumbnailimage/jpeg5501http://repositorio.ufsm.br/bitstream/1/10400/3/ADRIANE%20NUNES.pdf.jpgb433bfee59f433fb5f48fb949c8559e3MD531/104002022-08-23 12:16:28.286oai:repositorio.ufsm.br:1/10400Repositório Institucionalhttp://repositorio.ufsm.br/PUBhttp://repositorio.ufsm.br/oai/requestopendoar:39132022-08-23T15:16:28Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false |
dc.title.por.fl_str_mv |
Estudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatos |
dc.title.alternative.eng.fl_str_mv |
Study of the influence of chemical modifiers in lead determination by GF AAS in the presence of sulphates |
title |
Estudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatos |
spellingShingle |
Estudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatos Nunes, Adriane Medeiros Química Quimica analítica Chumbo CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Estudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatos |
title_full |
Estudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatos |
title_fullStr |
Estudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatos |
title_full_unstemmed |
Estudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatos |
title_sort |
Estudo da influência de modificadores químicos para a determinação de chumbo por GF AAS na presença de sulfatos |
author |
Nunes, Adriane Medeiros |
author_facet |
Nunes, Adriane Medeiros |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
Flores, Érico Marlon de Moraes |
dc.contributor.advisor1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782125T8 |
dc.contributor.referee1.fl_str_mv |
Mortari, Sergio Roberto |
dc.contributor.referee1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4721640J6 |
dc.contributor.referee2.fl_str_mv |
Pozebon, Dirce |
dc.contributor.referee2Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792312U6 |
dc.contributor.authorLattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4735597D6 |
dc.contributor.author.fl_str_mv |
Nunes, Adriane Medeiros |
contributor_str_mv |
Flores, Érico Marlon de Moraes Mortari, Sergio Roberto Pozebon, Dirce |
dc.subject.por.fl_str_mv |
Química Quimica analítica Chumbo |
topic |
Química Quimica analítica Chumbo CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.cnpq.fl_str_mv |
CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
Lead determination by graphite furnace atomic absorption spectrometry may be affected by some interferences. Several authors have reported that lead determination may be affected in the presence of some salts (carbonates chloride, nitrate and sulphate). Sulphates have been highlighted as potential interferents in lead determination. Interferences as analytical signal suppression and high background signal may be observed, even at low sulphate concentration. The main goal of this work was to verify the interferences caused during lead atomization in the presence of CaSO4, Na2SO4, FeSO4 e (NH4)2SO4, and try to minimize the interferences using chemical modifiers. This work was developed using a lead reference solution (10 μgl-1). This solution was placed into graphite furnace (10 μl), an amount corresponding to 100 pg lead, in the presence of different amounts of sulphate. It was observed signal suppression and high background signals. However, interferences caused by Na2SO4, FeSO4 e (NH4)2SO4 were minimized by optimization of pyrolysis and atomization temperatures. On the other hand, interferences caused by CaSO4 (27 μg) produced suppression in the analytical signal (66%), and they were just corrected by the use of chemical modifiers. This suppression effect was corrected using 3 μg Pd, and background signal was negligible in the presence of 5 μg Pd. It was verified that organic modifiers (ascorbic, oxalic and citric acid) were also efficient as chemical modifiers to correct the interferences observed in the presence of this salt. At optimized conditions in the presence of CaSO4, lead was determined in plaster samples (CaSO4.2H2O). The lead amount in these samples was smaller than the limit of detection. It was necessary the use of spiked samples to verify the performance of the developed method. Analyte recovery in the presence of ascorbic acid at the optimized pyrolysis and atomization temperatures was close to 100%. In this way, the use of organic chemical modifiers, as ascorbic acid, may be considered a reliable an relatively inexpensive procedure (when compared to the use of Pd) for the minimization of the interferences caused by calcium sulfate for lead determination by GF AAS. |
publishDate |
2005 |
dc.date.issued.fl_str_mv |
2005-03-03 |
dc.date.accessioned.fl_str_mv |
2008-02-20 |
dc.date.available.fl_str_mv |
2008-02-20 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
NUNES, Adriane Medeiros. Study of the influence of chemical modifiers in lead determination by GF AAS in the presence of sulphates. 2005. 104 f. Dissertação (Mestrado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2005. |
dc.identifier.uri.fl_str_mv |
http://repositorio.ufsm.br/handle/1/10400 |
identifier_str_mv |
NUNES, Adriane Medeiros. Study of the influence of chemical modifiers in lead determination by GF AAS in the presence of sulphates. 2005. 104 f. Dissertação (Mestrado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2005. |
url |
http://repositorio.ufsm.br/handle/1/10400 |
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