dc.contributorUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T14:19:35Z
dc.date.accessioned2022-10-05T15:18:41Z
dc.date.available2014-05-20T14:19:35Z
dc.date.available2022-10-05T15:18:41Z
dc.date.created2014-05-20T14:19:35Z
dc.date.issued2007-04-01
dc.identifierQuímica Nova. Sociedade Brasileira de Química, v. 30, n. 2, p. 308-311, 2007.
dc.identifier0100-4042
dc.identifierhttp://hdl.handle.net/11449/25907
dc.identifier10.1590/S0100-40422007000200013
dc.identifierS0100-40422007000200013
dc.identifierS0100-40422007000200013.pdf
dc.identifier8708735699846578
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/3898954
dc.description.abstractA 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.
dc.languagepor
dc.publisherSociedade Brasileira de Química
dc.relationQuímica Nova
dc.relation0.646
dc.relation0,255
dc.rightsAcesso aberto
dc.sourceSciELO
dc.subjectphosphite
dc.subjecttitrimetry
dc.subjectiodine
dc.titleMétodo titrimétrico para determinar fosfito em amostras agroindustriais
dc.typeArtigo


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