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Type: Artigo de periódico
Title: Uso de membranas de Nafion para a construção de sensores ópticos para medidas de pH
Title Alternative: Use of Nafion® membranes for the construction of optical sensors for pH measurements
Author: Pinheiro, Silvia Cristina Lopes
Raimundo Jr, Ivo M.
Abstract: The behaviour of Nafion® polymeric membranes containing acid-base dyes, bromothymol blue (BB) and methyl violet (MV), were studied aiming at constructing an optical sensor for pH measurement. BB revealed to be inadequate for developing sensing phases due to the electrostatic repulsion between negative groups of their molecules and the negative charge of the sulfonate group of the Nafion®, which causes leaching of the dye from the membrane. On the other hand, MV showed to be suitable due to the presence of positive groups in its structure. The membrane prepared from a methanolic solution whose Nafion®/dye molar ratio was 20 presented the best analytical properties, changing its color from green to violet in the pH range from 0.6 to 3.0. The membrane can be prepared with good reproducibility, presenting durability of ca. 6 months and response time of 22 s, making possible its use for pH determination in flow analysis systems.
Subject: optical sensor
pH sensor
Editor: Sociedade Brasileira de Química
Citation: Química Nova. Sociedade Brasileira de Química, v. 28, n. 5, p. 932-936, 2005.
Rights: aberto
Identifier DOI: 10.1590/S0100-40422005000500036
Date Issue: 1-Oct-2005
Appears in Collections:Unicamp - Artigos e Outros Documentos

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