Método titrimétrico para determinar fosfito em amostras agroindustriais

Detalhes bibliográficos
Autor(a) principal: Franzini, Vanessa Pezza [UNESP]
Data de Publicação: 2007
Outros Autores: Gomes Neto, José Anchieta [UNESP]
Tipo de documento: Artigo
Idioma: por
Título da fonte: Repositório Institucional da UNESP
Texto Completo: http://dx.doi.org/10.1590/S0100-40422007000200013
http://hdl.handle.net/11449/25907
Resumo: A new titrimetric method for the determination of phosphite in fertilizer samples, based on reaction of H3PO3 with standard iodine solution in neutral media, is proposed. Diluted samples containing ca. 0.4% m/v P2O5 are heated and titrated with 0.05 mol L-1 iodine standard until the solution becomes faint yellow. Back titration is also feasible: a slight excess of titrant is added followed by starch indicator and titration is completed taking as the end point the change in color from blue to colorless. The influence of chemical composition and pH of buffers, temperature and foreign species on waiting time and end-point detection were investigated. For the Na2HPO4/NaH2PO4 buffer (pH 6.8) at 70 °C, the titration time was 10 min, corresponding to about 127 mg iodine, 200 mg KI and 174 mg Na2HPO4 and 176 mg NaH2PO4 consumed per determination. Accuracy was checked for phosphite determination in seven fertilizer samples. Results obtained by the proposed procedure were in agreement with those obtained by spectrophotometry at 95% confidence level. The R.S.D. (n=10) for direct and back titration was 0.4% and 1.3% respectively.
id UNSP_3d3668f46d2abe5f5535b96e94c89a3f
oai_identifier_str oai:repositorio.unesp.br:11449/25907
network_acronym_str UNSP
network_name_str Repositório Institucional da UNESP
repository_id_str 2946
spelling Método titrimétrico para determinar fosfito em amostras agroindustriaisTitrimetric method for phosphite determination in agricultural chemical samplesphosphitetitrimetryiodineA new titrimetric method for the determination of phosphite in fertilizer samples, based on reaction of H3PO3 with standard iodine solution in neutral media, is proposed. Diluted samples containing ca. 0.4% m/v P2O5 are heated and titrated with 0.05 mol L-1 iodine standard until the solution becomes faint yellow. Back titration is also feasible: a slight excess of titrant is added followed by starch indicator and titration is completed taking as the end point the change in color from blue to colorless. The influence of chemical composition and pH of buffers, temperature and foreign species on waiting time and end-point detection were investigated. For the Na2HPO4/NaH2PO4 buffer (pH 6.8) at 70 °C, the titration time was 10 min, corresponding to about 127 mg iodine, 200 mg KI and 174 mg Na2HPO4 and 176 mg NaH2PO4 consumed per determination. Accuracy was checked for phosphite determination in seven fertilizer samples. Results obtained by the proposed procedure were in agreement with those obtained by spectrophotometry at 95% confidence level. The R.S.D. (n=10) for direct and back titration was 0.4% and 1.3% respectively.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Estadual Paulista Instituto de Química Departamento de Química AnalíticaUniversidade Estadual Paulista Instituto de Química Departamento de Química AnalíticaSociedade Brasileira de QuímicaUniversidade Estadual Paulista (Unesp)Franzini, Vanessa Pezza [UNESP]Gomes Neto, José Anchieta [UNESP]2014-05-20T14:19:35Z2014-05-20T14:19:35Z2007-04-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article308-311application/pdfhttp://dx.doi.org/10.1590/S0100-40422007000200013Química Nova. Sociedade Brasileira de Química, v. 30, n. 2, p. 308-311, 2007.0100-4042http://hdl.handle.net/11449/2590710.1590/S0100-40422007000200013S0100-40422007000200013S0100-40422007000200013.pdf8708735699846578SciELOreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPporQuímica Nova0.6460,255info:eu-repo/semantics/openAccess2023-11-30T06:15:56Zoai:repositorio.unesp.br:11449/25907Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T19:08:42.681605Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false
dc.title.none.fl_str_mv Método titrimétrico para determinar fosfito em amostras agroindustriais
Titrimetric method for phosphite determination in agricultural chemical samples
title Método titrimétrico para determinar fosfito em amostras agroindustriais
spellingShingle Método titrimétrico para determinar fosfito em amostras agroindustriais
Franzini, Vanessa Pezza [UNESP]
phosphite
titrimetry
iodine
title_short Método titrimétrico para determinar fosfito em amostras agroindustriais
title_full Método titrimétrico para determinar fosfito em amostras agroindustriais
title_fullStr Método titrimétrico para determinar fosfito em amostras agroindustriais
title_full_unstemmed Método titrimétrico para determinar fosfito em amostras agroindustriais
title_sort Método titrimétrico para determinar fosfito em amostras agroindustriais
author Franzini, Vanessa Pezza [UNESP]
author_facet Franzini, Vanessa Pezza [UNESP]
Gomes Neto, José Anchieta [UNESP]
author_role author
author2 Gomes Neto, José Anchieta [UNESP]
author2_role author
dc.contributor.none.fl_str_mv Universidade Estadual Paulista (Unesp)
dc.contributor.author.fl_str_mv Franzini, Vanessa Pezza [UNESP]
Gomes Neto, José Anchieta [UNESP]
dc.subject.por.fl_str_mv phosphite
titrimetry
iodine
topic phosphite
titrimetry
iodine
description A new titrimetric method for the determination of phosphite in fertilizer samples, based on reaction of H3PO3 with standard iodine solution in neutral media, is proposed. Diluted samples containing ca. 0.4% m/v P2O5 are heated and titrated with 0.05 mol L-1 iodine standard until the solution becomes faint yellow. Back titration is also feasible: a slight excess of titrant is added followed by starch indicator and titration is completed taking as the end point the change in color from blue to colorless. The influence of chemical composition and pH of buffers, temperature and foreign species on waiting time and end-point detection were investigated. For the Na2HPO4/NaH2PO4 buffer (pH 6.8) at 70 °C, the titration time was 10 min, corresponding to about 127 mg iodine, 200 mg KI and 174 mg Na2HPO4 and 176 mg NaH2PO4 consumed per determination. Accuracy was checked for phosphite determination in seven fertilizer samples. Results obtained by the proposed procedure were in agreement with those obtained by spectrophotometry at 95% confidence level. The R.S.D. (n=10) for direct and back titration was 0.4% and 1.3% respectively.
publishDate 2007
dc.date.none.fl_str_mv 2007-04-01
2014-05-20T14:19:35Z
2014-05-20T14:19:35Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://dx.doi.org/10.1590/S0100-40422007000200013
Química Nova. Sociedade Brasileira de Química, v. 30, n. 2, p. 308-311, 2007.
0100-4042
http://hdl.handle.net/11449/25907
10.1590/S0100-40422007000200013
S0100-40422007000200013
S0100-40422007000200013.pdf
8708735699846578
url http://dx.doi.org/10.1590/S0100-40422007000200013
http://hdl.handle.net/11449/25907
identifier_str_mv Química Nova. Sociedade Brasileira de Química, v. 30, n. 2, p. 308-311, 2007.
0100-4042
10.1590/S0100-40422007000200013
S0100-40422007000200013
S0100-40422007000200013.pdf
8708735699846578
dc.language.iso.fl_str_mv por
language por
dc.relation.none.fl_str_mv Química Nova
0.646
0,255
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 308-311
application/pdf
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 SciELO
reponame:Repositório Institucional da UNESP
instname:Universidade Estadual Paulista (UNESP)
instacron:UNESP
instname_str Universidade Estadual Paulista (UNESP)
instacron_str UNESP
institution UNESP
reponame_str Repositório Institucional da UNESP
collection Repositório Institucional da UNESP
repository.name.fl_str_mv Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)
repository.mail.fl_str_mv
_version_ 1808129025098383360