Internal standardization in graphite furnace atomic absorption spectrometry: Comparative use of As and Ge to minimize matrix effects on Se determination in milk

dc.contributor.authorde Oliveira, A. P.
dc.contributor.authorNeto, JAG
dc.contributor.authorNobrega, J. A.
dc.contributor.authorOliveira, P. V.
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniversidade Federal de São Carlos (UFSCar)
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.date.accessioned2014-05-20T15:30:09Z
dc.date.available2014-05-20T15:30:09Z
dc.date.issued2005-06-30
dc.description.abstractArsenic and germanium have been evaluated as internal standards to minimize matrix effects on the direct determination of selenium in milk by graphite furnace atomic absorption spectrometry (GFAAS) using tubes with integrated platform, pre-treated with W together with I'd as chemical modifier. The efficiency of As and Ge as internal standards for 25 mu g L-1 Se plus 500 mu g (L)-1 As or Ge in diluted (1 + 9 v/v) milk plus 1.0% (v/v) HNO3 was evaluated by means of correlation graphs plotted from the normalized absorbance signals (n = 20) of internal standard (axis gamma) versus analyte (axis x). The equations that describe the linear regression were: A(As)= - 0.004 +/- 0.019 +/- 1.02 + 0.019 A(Se) (r=0.9967 +/- 0.005); A(Ge)= - 0.0 17 +/- 0.015 + 1.01 +/- 0.015 A(Se) (r = 0.9978 +/- 0.004). Samples and reference solutions were automatically spiked with 500 mu g L-1 Ge or As and 1.0% (v/v) HNO3 by the autosampler. For 20 mu L of aqueous standard solutions, analytical curves in the 5.00-40.0 mu g L-1 Se range were established using the ratio of Se absorbance to internal standard absorbance (A(Se)A(IS)) versus analyte concentration, and good linear correlations were obtained. The characteristic mass was 40 pg Se. Limits of detection were 0.55 and 0.40 mu g L-1 with As and Ge as the internal standard, respectively. Relative standard deviations (RSD) for a sample containing 25 mu g L-1 Se were 1.2% and 1.0% (n = 12) using As and Ge, respectively. The RSD without internal standardization was about 6%. The accuracy of the proposed method was evaluated by an addition-recovery experiment and all recovered values were in the 99-105% range with IS and in the 70-80% range without IS. Using Ge as the internal standard, results of analysis of standard reference materials were in agreement with certified values at a 95% confidence level. The selenium concentration for 10 analyzed milk samples varied from 5.0 to 20 mu g L-1. (c) 2005 Elsevier B.V. All rights reserved.en
dc.description.affiliationUniv Estadual Paulista, Dept Quim Analit, BR-14801970 Araraquara, SP, Brazil
dc.description.affiliationUniv Fed Sao Carlos, Dept Quim, BR-13560970 Sao Carlos, SP, Brazil
dc.description.affiliationUniv São Paulo, Inst Quim, BR-05513970 São Paulo, SP, Brazil
dc.description.affiliationUnespUniv Estadual Paulista, Dept Quim Analit, BR-14801970 Araraquara, SP, Brazil
dc.format.extent681-686
dc.identifierhttp://dx.doi.org/10.1016/j.sab.2005.02.005
dc.identifier.citationSpectrochimica Acta Part B-atomic Spectroscopy. Oxford: Pergamon-Elsevier B.V., v. 60, n. 5, p. 681-686, 2005.
dc.identifier.doi10.1016/j.sab.2005.02.005
dc.identifier.issn0584-8547
dc.identifier.urihttp://hdl.handle.net/11449/39589
dc.identifier.wosWOS:000230022200016
dc.language.isoeng
dc.publisherElsevier B.V.
dc.relation.ispartofSpectrochimica Acta Part B-atomic Spectroscopy
dc.relation.ispartofjcr2.854
dc.relation.ispartofsjr0,960
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.subjectmilkpt
dc.subjectinternal standardizationpt
dc.subjectGFAASpt
dc.subjectseleniumpt
dc.titleInternal standardization in graphite furnace atomic absorption spectrometry: Comparative use of As and Ge to minimize matrix effects on Se determination in milken
dc.typeArtigo
dcterms.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dcterms.rightsHolderElsevier B.V.
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Química, Araraquarapt

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