Phosphite determination in fertilizers after online sequential sample preparation in a flow injection system

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dc.contributor.authorRoberta Dametto, Patricia
dc.contributor.authorPezza Franzini, Vanessa
dc.contributor.authorGomes Neto, José Anchieta [UNESP]
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:21:09Z
dc.date.available2014-05-20T15:21:09Z
dc.date.issued2007-07-26
dc.description.abstractA flow injection spectrophotometric system is proposed for phosphite determination in fertilizers by the molybdenum blue method after the processing of each sample two times on-line without and with an oxidizing step. The flow system was designed to add sulfuric acid or permanganate solutions alternately into the system by simply displacing the injector-commutator from one resting position to another, allowing the determination of phosphate and total phosphate, respectively. The concentration of phosphite is obtained then by difference between the two measurents. The influence of flow rates, sample volume, and dimension of flow line connecting the injector-commutator to the main analytical channel was evaluated. The proposed method was applied to phosphite determination in commercial liquid fertilizers. Results obtained with the proposed FIA system were not statistically different from those obtained by titrimetry at the 95% confidence level. In addition, recoveries within 94 and 100% of spiked fertilizers were found. The relative standard deviation (n = 12) related to the phosphite-converted-phosphate peak alone was <= 3.5% for 800 mg L-1 P (phoshite) solution. Precision due to the differences of total phosphate and phosphate was 1.1% for 10 mg L-1 P (phosphate) + 3000 mg L-1 P (phosphite) solution. The sampling rate was calculated as 15 determinations per hour, and the reagent consumption was about 6.3 mg of KMnO4, 200 mg of (NH4)(6)Mo7O24 center dot 4H(2)O, and 40 mg of ascorbic acid per measurement.en
dc.description.affiliationUniv Estadual Paulista, Inst Quim, Dept Quim Analit, BR-14801 Araraquara, SP, Brazil
dc.description.affiliationUnespUniv Estadual Paulista, Inst Quim, Dept Quim Analit, BR-14801 Araraquara, SP, Brazil
dc.format.extent5980-5983
dc.identifierhttp://dx.doi.org/10.1021/jf0707435
dc.identifier.citationJournal of Agricultural and Food Chemistry. Washington: Amer Chemical Soc, v. 55, n. 15, p. 5980-5983, 2007.
dc.identifier.doi10.1021/jf0707435
dc.identifier.issn0021-8561
dc.identifier.lattes8708735699846578
dc.identifier.urihttp://hdl.handle.net/11449/32323
dc.identifier.wosWOS:000248085300012
dc.language.isoeng
dc.publisherAmer Chemical Soc
dc.relation.ispartofJournal of Agricultural and Food Chemistry
dc.relation.ispartofjcr3.412
dc.relation.ispartofsjr1,269
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.subjectfertilizerpt
dc.subjectphosphitept
dc.subjectFIApt
dc.subjectspectrophotometrypt
dc.titlePhosphite determination in fertilizers after online sequential sample preparation in a flow injection systemen
dc.typeArtigo
dcterms.licensehttp://pubs.acs.org/paragonplus/copyright/jpa_form_a.pdf
dcterms.rightsHolderAmer Chemical Soc
unesp.author.lattes8708735699846578
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Química, Araraquarapt

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Artigos - Química Analítica - IQ