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Type: Artigo de periódico
Title: Dissolved oxygen sensor based on cobalt tetrasulphonated phthalocyanine immobilized in poly-L-lysine film onto glassy carbon electrode
Author: Luz, RDS
Damos, FS
Tanaka, AA
Kubota, LT
Abstract: A simple and efficient method for determining dissolved oxygen at pH 6.5 is proposed using differential pulse voltammetry (DPV) and chronoamperometry. The sensor was prepared by modifying a glassy carbon (GC) electrode surface with a cobalt tetrasulphonated phthalocyanine (CoTSPc) immobilized in a poly-L-lysine (PLL) film. This sensor showed excellent catalytic activity and stability for oxygen reduction. With this modified electrode the reduction potential of the oxygen was shifted about 200 mV toward less negative value, presenting a peak current much higher than those measured on a bare GC electrode. The linear response range, sensitivity and detection limit obtained were, respectively, 0.2-8.0 mg l(-1), 11.0 mu A l mg(-1) cm(-2) and 96 mu g l(-1) for chronoamperometry and 0.2-8.0 mg l(-1), 18.3 mu A l mg(-1) cm(-2) and 72 mu g l(-1) for DPV. The repeatability and reproductibility of the proposed sensor evaluated in term of relative standard deviation were, respectively, 4.5% and 4.8% for 10 measurements of a 8.0 mg l(-1) oxygen solution. The number of electrons involved in oxygen reduction, the heterogenous rate constant (k) and the diffusion coefficient (D.) value were evaluated by cyclic voltammetry and with a rotating disk electrode (RDE). These studies showed that two electrons are involved in the oxygen reduction. An average value of the heterogenous rate constant was found to be 4.25 x 10(4) mol(-1) l s(-1) and the diffusion coefficient was 2.0 x 10(-5) cm(2) s(-1). (c) 2005 Elsevier B.V. All rights reserved.
Subject: sensor
dissolved oxygen
cobalt tetrasulphonated phthalocyanine
Country: Suíça
Editor: Elsevier Science Sa
Citation: Sensors And Actuators B-chemical. Elsevier Science Sa, v. 114, n. 2, n. 1019, n. 1027, 2006.
Rights: fechado
Identifier DOI: 10.1016/j.snb.2005.07.063
Date Issue: 2006
Appears in Collections:Unicamp - Artigos e Outros Documentos

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