Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry

Detalhes bibliográficos
Autor(a) principal: Oliveira,Ulisses M. F. de
Data de Publicação: 2004
Outros Autores: Lichtig,Jaim, Masini,Jorge C.
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Journal of the Brazilian Chemical Society (Online)
Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532004000500020
Resumo: This paper presents an evaluation of a Nafion coated glassy carbon electrode for determination of paraquat in river water and urine by differential pulse voltammetry. The film was formed applying 4 µL of a 1% (m/v) Nafion solution, which was evaporated under an infrared light. The maximum signal to noise ratio was obtained using a 40 mmol L-1 Britton-Robinson buffer at pH 12 as supporting electrolyte. For an accumulation time of 5.0 min in open circuit, the limit of detection was 0.7 µg L-1, while the quantification limit was 1.0 µg L-1, with a linear dynamic range up to 12 µg L-1. In these conditions, a sequence of ten experiments lead to a relative standard deviation of peak current of 2.2% for a 10 µg L-1 paraquat solution. Ion pair formation in solution was the major factor of error in analysis. Despite the film to avoid adsorption of anionic species at the electrode surface, paraquat suffers strong association in solution with humic substances, proteins, clays, anionic surfactants, etc. These interactions decrease the accumulation of paraquat in the Nafion film and, as a consequence, the magnitude of the reduction peak, requiring that quantifications have to be made by standard addition. Recoveries between 87 and 106% were obtained for river waters and urine samples spiked with 1.0 and 3.0 µg L-1 paraquat.
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spelling Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetryparaquat determinationriver waterurinemodified electrodevoltammetryion exchangeThis paper presents an evaluation of a Nafion coated glassy carbon electrode for determination of paraquat in river water and urine by differential pulse voltammetry. The film was formed applying 4 µL of a 1% (m/v) Nafion solution, which was evaporated under an infrared light. The maximum signal to noise ratio was obtained using a 40 mmol L-1 Britton-Robinson buffer at pH 12 as supporting electrolyte. For an accumulation time of 5.0 min in open circuit, the limit of detection was 0.7 µg L-1, while the quantification limit was 1.0 µg L-1, with a linear dynamic range up to 12 µg L-1. In these conditions, a sequence of ten experiments lead to a relative standard deviation of peak current of 2.2% for a 10 µg L-1 paraquat solution. Ion pair formation in solution was the major factor of error in analysis. Despite the film to avoid adsorption of anionic species at the electrode surface, paraquat suffers strong association in solution with humic substances, proteins, clays, anionic surfactants, etc. These interactions decrease the accumulation of paraquat in the Nafion film and, as a consequence, the magnitude of the reduction peak, requiring that quantifications have to be made by standard addition. Recoveries between 87 and 106% were obtained for river waters and urine samples spiked with 1.0 and 3.0 µg L-1 paraquat.Sociedade Brasileira de Química2004-10-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532004000500020Journal of the Brazilian Chemical Society v.15 n.5 2004reponame:Journal of the Brazilian Chemical Society (Online)instname:Sociedade Brasileira de Química (SBQ)instacron:SBQ10.1590/S0103-50532004000500020info:eu-repo/semantics/openAccessOliveira,Ulisses M. F. deLichtig,JaimMasini,Jorge C.eng2004-11-10T00:00:00Zoai:scielo:S0103-50532004000500020Revistahttp://jbcs.sbq.org.brONGhttps://old.scielo.br/oai/scielo-oai.php||office@jbcs.sbq.org.br1678-47900103-5053opendoar:2004-11-10T00:00Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ)false
dc.title.none.fl_str_mv Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry
title Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry
spellingShingle Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry
Oliveira,Ulisses M. F. de
paraquat determination
river water
urine
modified electrode
voltammetry
ion exchange
title_short Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry
title_full Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry
title_fullStr Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry
title_full_unstemmed Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry
title_sort Evaluation of a nafion coated glassy carbon electrode for determination of paraquat by differential pulse voltammetry
author Oliveira,Ulisses M. F. de
author_facet Oliveira,Ulisses M. F. de
Lichtig,Jaim
Masini,Jorge C.
author_role author
author2 Lichtig,Jaim
Masini,Jorge C.
author2_role author
author
dc.contributor.author.fl_str_mv Oliveira,Ulisses M. F. de
Lichtig,Jaim
Masini,Jorge C.
dc.subject.por.fl_str_mv paraquat determination
river water
urine
modified electrode
voltammetry
ion exchange
topic paraquat determination
river water
urine
modified electrode
voltammetry
ion exchange
description This paper presents an evaluation of a Nafion coated glassy carbon electrode for determination of paraquat in river water and urine by differential pulse voltammetry. The film was formed applying 4 µL of a 1% (m/v) Nafion solution, which was evaporated under an infrared light. The maximum signal to noise ratio was obtained using a 40 mmol L-1 Britton-Robinson buffer at pH 12 as supporting electrolyte. For an accumulation time of 5.0 min in open circuit, the limit of detection was 0.7 µg L-1, while the quantification limit was 1.0 µg L-1, with a linear dynamic range up to 12 µg L-1. In these conditions, a sequence of ten experiments lead to a relative standard deviation of peak current of 2.2% for a 10 µg L-1 paraquat solution. Ion pair formation in solution was the major factor of error in analysis. Despite the film to avoid adsorption of anionic species at the electrode surface, paraquat suffers strong association in solution with humic substances, proteins, clays, anionic surfactants, etc. These interactions decrease the accumulation of paraquat in the Nafion film and, as a consequence, the magnitude of the reduction peak, requiring that quantifications have to be made by standard addition. Recoveries between 87 and 106% were obtained for river waters and urine samples spiked with 1.0 and 3.0 µg L-1 paraquat.
publishDate 2004
dc.date.none.fl_str_mv 2004-10-01
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
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dc.identifier.uri.fl_str_mv http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532004000500020
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532004000500020
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 10.1590/S0103-50532004000500020
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv text/html
dc.publisher.none.fl_str_mv Sociedade Brasileira de Química
publisher.none.fl_str_mv Sociedade Brasileira de Química
dc.source.none.fl_str_mv Journal of the Brazilian Chemical Society v.15 n.5 2004
reponame:Journal of the Brazilian Chemical Society (Online)
instname:Sociedade Brasileira de Química (SBQ)
instacron:SBQ
instname_str Sociedade Brasileira de Química (SBQ)
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institution SBQ
reponame_str Journal of the Brazilian Chemical Society (Online)
collection Journal of the Brazilian Chemical Society (Online)
repository.name.fl_str_mv Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ)
repository.mail.fl_str_mv ||office@jbcs.sbq.org.br
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