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dc.typeArtigo de periódicopt_BR
dc.titleRing-oven Based Preconcentration Technique For Microanalysis: Simultaneous Determination Of Na, Fe, And Cu In Fuel Ethanol By Laser Induced Breakdown Spectroscopy.pt_BR
dc.contributor.authorCortez, Julianapt_BR
dc.contributor.authorPasquini, Celiopt_BR
unicamp.authorJuliana Cortez, Chemistry Institute, Department of Analytical Chemistry, UNICAMP, Caixa Postal 6154, CEP: 13087-971, Campinas , SP, Brazil.pt_BR Pasquini,pt
dc.description.abstractThe ring-oven technique, originally applied for classical qualitative analysis in the years 1950s to 1970s, is revisited to be used in a simple though highly efficient and green procedure for analyte preconcentration prior to its determination by the microanalytical techniques presently available. The proposed preconcentration technique is based on the dropwise delivery of a small volume of sample to a filter paper substrate, assisted by a flow-injection-like system. The filter paper is maintained in a small circular heated oven (the ring oven). Drops of the sample solution diffuse by capillarity from the center to a circular area of the paper substrate. After the total sample volume has been delivered, a ring with a sharp (c.a. 350 μm) circular contour, of about 2.0 cm diameter, is formed on the paper to contain most of the analytes originally present in the sample volume. Preconcentration coefficients of the analyte can reach 250-fold (on a m/m basis) for a sample volume as small as 600 μL. The proposed system and procedure have been evaluated to concentrate Na, Fe, and Cu in fuel ethanol, followed by simultaneous direct determination of these species in the ring contour, employing the microanalytical technique of laser induced breakdown spectroscopy (LIBS). Detection limits of 0.7, 0.4, and 0.3 μg mL(-1) and mean recoveries of (109 ± 13)%, (92 ± 18)%, and (98 ± 12)%, for Na, Fe, and Cu, respectively, were obtained in fuel ethanol. It is possible to anticipate the application of the technique, coupled to modern microanalytical and multianalyte techniques, to several analytical problems requiring analyte preconcentration and/or sample stabilization.en
dc.relation.ispartofAnalytical Chemistrypt_BR
dc.relation.ispartofabbreviationAnal. Chem.pt_BR
dc.identifier.citationAnalytical Chemistry. v. 85, n. 3, p. 1547-54, 2013-Feb.pt_BR
dc.description.provenanceMade available in DSpace on 2015-11-27T13:32:40Z (GMT). No. of bitstreams: 1 pmed_23252633.pdf: 1025007 bytes, checksum: b35163d1ae488dde434cb1e66cf9b3a5 (MD5) Previous issue date: 2013en
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