Electrochemical Quartz Crystal Impedance Study of Redox Hydrogel Mediators for Amperometric Enzyme Electrodes

Quartz crystal impedance around the resonant frequency at 10 MHz of a composite quartz crystal resonator has been studied simultaneously with cyclic voltammetry. A modified quartz crystal with a redox hydrogel (poly(allylamine)-ferrocene cross-linked with glucose oxidase) and immersed in liquid elec...

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Autores principales: Etchenique, R.A., Calvo, E.J.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00032700_v69_n23_p4833_Etchenique
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00032700_v69_n23_p4833_Etchenique2023-10-03T13:55:58Z Electrochemical Quartz Crystal Impedance Study of Redox Hydrogel Mediators for Amperometric Enzyme Electrodes Etchenique, R.A. Calvo, E.J. Quartz crystal impedance around the resonant frequency at 10 MHz of a composite quartz crystal resonator has been studied simultaneously with cyclic voltammetry. A modified quartz crystal with a redox hydrogel (poly(allylamine)-ferrocene cross-linked with glucose oxidase) and immersed in liquid electrolyte was used. Impedance parameters (Rf and XLf) of the surface redox gel film were obtained by fitting the resonator transfer function |Vo/Vi| vs ω to a BVD equivalent circuit and analyzed with the multiple nonpiezoelectric layer model of Martin. Two limiting hydrogel layers of the same composition were studied while oxidizing and reducing the ferrocene/ferricenium moieties attached to the swollen polymer backbone: thin and thick redox hydrogel films. For the thin films, the Sauerbrey approximation was valid. The mass/thickness and film viscosity changes that resulted from the anion and water exchange were evaluated while redox switching the polymer on the assumption of negligible storage modulus G′ and a density of 1. For thick gel layers, on the other hand, the penetration depth of the acoustic wave was far less than the film thickness, and a liquid-like behavior was apparent. Film storage modulus and film loss modulus were simultaneously evaluated with the cyclic voltammetry. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00032700_v69_n23_p4833_Etchenique
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description Quartz crystal impedance around the resonant frequency at 10 MHz of a composite quartz crystal resonator has been studied simultaneously with cyclic voltammetry. A modified quartz crystal with a redox hydrogel (poly(allylamine)-ferrocene cross-linked with glucose oxidase) and immersed in liquid electrolyte was used. Impedance parameters (Rf and XLf) of the surface redox gel film were obtained by fitting the resonator transfer function |Vo/Vi| vs ω to a BVD equivalent circuit and analyzed with the multiple nonpiezoelectric layer model of Martin. Two limiting hydrogel layers of the same composition were studied while oxidizing and reducing the ferrocene/ferricenium moieties attached to the swollen polymer backbone: thin and thick redox hydrogel films. For the thin films, the Sauerbrey approximation was valid. The mass/thickness and film viscosity changes that resulted from the anion and water exchange were evaluated while redox switching the polymer on the assumption of negligible storage modulus G′ and a density of 1. For thick gel layers, on the other hand, the penetration depth of the acoustic wave was far less than the film thickness, and a liquid-like behavior was apparent. Film storage modulus and film loss modulus were simultaneously evaluated with the cyclic voltammetry.
format JOUR
author Etchenique, R.A.
Calvo, E.J.
spellingShingle Etchenique, R.A.
Calvo, E.J.
Electrochemical Quartz Crystal Impedance Study of Redox Hydrogel Mediators for Amperometric Enzyme Electrodes
author_facet Etchenique, R.A.
Calvo, E.J.
author_sort Etchenique, R.A.
title Electrochemical Quartz Crystal Impedance Study of Redox Hydrogel Mediators for Amperometric Enzyme Electrodes
title_short Electrochemical Quartz Crystal Impedance Study of Redox Hydrogel Mediators for Amperometric Enzyme Electrodes
title_full Electrochemical Quartz Crystal Impedance Study of Redox Hydrogel Mediators for Amperometric Enzyme Electrodes
title_fullStr Electrochemical Quartz Crystal Impedance Study of Redox Hydrogel Mediators for Amperometric Enzyme Electrodes
title_full_unstemmed Electrochemical Quartz Crystal Impedance Study of Redox Hydrogel Mediators for Amperometric Enzyme Electrodes
title_sort electrochemical quartz crystal impedance study of redox hydrogel mediators for amperometric enzyme electrodes
url http://hdl.handle.net/20.500.12110/paper_00032700_v69_n23_p4833_Etchenique
work_keys_str_mv AT etcheniquera electrochemicalquartzcrystalimpedancestudyofredoxhydrogelmediatorsforamperometricenzymeelectrodes
AT calvoej electrochemicalquartzcrystalimpedancestudyofredoxhydrogelmediatorsforamperometricenzymeelectrodes
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