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Type: Artigo de periódico
Title: Development of a new FIA-potentiometric sensor for dopamine based on EVA-copper(II) ions
Author: Junior, LR
Fernandes, JCB
Neto, GD
Kubota, LT
Abstract: A how injection analysis (FIA) system using a tubular electrode based on the redox properties of copper(II) ions immobilized in a poly(ethylene-co-vinyl acetate) (EVA) membrane was developed for dopamine determination. The Cu2+ was trapped in the EVA (40% m/m) matrix and dispersed on the surface of a graphite-epoxy flow-through electrode. The electrode based on the dopamine oxidation catalyzed by Cu2+ exhibited a near-Nernstian response (83.2 +/- 0.2 mV decade(-1)) for dopamine concentration between 1.0 x 10(-3) and 1.0 x 10(-2) mol l(-1) (r = 0.9992), employing 0.25 mol l(-1) KH2PO4 buffer, containing 0.1 mol l(-1) H2O2 at pH 7.0, as a carrier solution. The potentiometric-FIA system allows an analytical frequency of about 25 samples per hour with a good precision (variance lower than 4.2%). The best potentiometric response was achieved using an EVA membrane containing 5.0% (m/m) Cu2+ ions. The use of hydrogen peroxide in a flow-system makes an efficient reoxidation of the Cu1+ ions possible in the EVA membrane. The relative standard deviation for dopamine determination in pharmaceutical samples, without any previous treatment, was about 4.7%. The useful lifetime for the dopamine sensor was longer than 3 months, in continuous use, (C) 2000 Elsevier Science S.A. All rights reserved.
Subject: potentiometric sensor
EVA membrane
dopamine determination
Country: Suíça
Editor: Elsevier Science Sa
Citation: Journal Of Electroanalytical Chemistry. Elsevier Science Sa, v. 481, n. 1, n. 34, n. 41, 2000.
Rights: fechado
Identifier DOI: 10.1016/S0022-0728(99)00474-X
Date Issue: 2000
Appears in Collections:Unicamp - Artigos e Outros Documentos

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