Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/61400
Type: Artigo de periódico
Title: Determination of malic acid in real samples by using enzyme immobilized reactors and amperometric detection
Author: Manzoli, A
Tomita, LSN
Fertonani, FL
de Oliveira-Neto, G
Mascini, M
Yamanaka, H
Abstract: The malate dehydrogenase (MDH) and ascorbate oxidase were immobilized independently, onto silanized controlled porous silica and packed in a tygon tube. The reactors were inserted in the flow system, and the malic acid was determined by measurement of NADH produced by enzymatic reaction. The NADH was reoxidized in a wall jet cell that consisted of spectrographic graphite, Ag/AgCl, KCl(sat), and steel needle as work, reference, and counter electrodes, respectively. The current intensities were measured at 390 mV. The malate calibration curve shows a linear range from 5.0 x 10(-6) to 1.0 x 10(-4) molL(-1), the lifetime was 40 analyses, after that a decrease of 20% on the response is observed. Three different citric juices were analyzed and a good correlation between the proposed method and spectrophotometric commercial kit were obtained.
Subject: citrus juice
malic acid
malate dehydrogenase
ascorbic acid
Country: EUA
Editor: Taylor & Francis Inc
Rights: fechado
Identifier DOI: 10.1081/AL-120039428
Date Issue: 2004
Appears in Collections:Unicamp - Artigos e Outros Documentos

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