Poly(aniline) microelectrodes for ascorbate measurements
Poly(aniline) microelectrodes for ascorbate measurements
The aim of this research was the production of a needle type microelectrode to monitor rapid changes of ascorbic acid, AA, in physiological fluids. Poly(aniline), PANi, composites have been shown to be excellent electrocatalytic surfaces for the oxidation of NADH and AA. Electrodeposition of PANi films on small platinum disc and elliptical microelectrodes was carried out under potentiodynamic and potentiostatic control. The effect of the electrolyte and counter ion were studied in order to produce reproducible, stable and conducting PANi films. Special attention was given to the final morphology of the resulting polymer film. Following previous work at Southampton University the incorporation of two poly(anions) was studied on a small scale: poly(vinylsulfonate), PVS, and poly(styrenesulfonate), PSS. In addition alkylated and crosslinked PANi microelectrodes were investigated as an alternative to PANi composites to retain PANi conductivity at neutral pH. The kinetic model proposed by Bartlett and Wallace on the RDE was compared with the data obtained at composite PANi microelectrodes. It was found that the counter ion plays an important role during ascorbate oxidation. The observed current responses to AA are half of the theoretical value for PANi-PSS microelectrodes. A different reaction mechanism is proposed for PANi-PVS and PANi-PSS where an ascorbate radical anion intermediate might be present for the later composite. The excellent electroanalytical properties shown by the modified PANi films were applied to real systems. PANi-PSS microelectrodes were used as amperometric sensors for AA in low volume of human plasma. PANi-PVS elliptical needle type microelectrodes were successfully applied for the detection of ascorbate in the substomatal cavities of Barley leaves.
University of Southampton
Martinez-Bonastre, Alejandro
46bc03cc-806c-436c-9335-b87889e6bd09
2007
Martinez-Bonastre, Alejandro
46bc03cc-806c-436c-9335-b87889e6bd09
Martinez-Bonastre, Alejandro
(2007)
Poly(aniline) microelectrodes for ascorbate measurements.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The aim of this research was the production of a needle type microelectrode to monitor rapid changes of ascorbic acid, AA, in physiological fluids. Poly(aniline), PANi, composites have been shown to be excellent electrocatalytic surfaces for the oxidation of NADH and AA. Electrodeposition of PANi films on small platinum disc and elliptical microelectrodes was carried out under potentiodynamic and potentiostatic control. The effect of the electrolyte and counter ion were studied in order to produce reproducible, stable and conducting PANi films. Special attention was given to the final morphology of the resulting polymer film. Following previous work at Southampton University the incorporation of two poly(anions) was studied on a small scale: poly(vinylsulfonate), PVS, and poly(styrenesulfonate), PSS. In addition alkylated and crosslinked PANi microelectrodes were investigated as an alternative to PANi composites to retain PANi conductivity at neutral pH. The kinetic model proposed by Bartlett and Wallace on the RDE was compared with the data obtained at composite PANi microelectrodes. It was found that the counter ion plays an important role during ascorbate oxidation. The observed current responses to AA are half of the theoretical value for PANi-PSS microelectrodes. A different reaction mechanism is proposed for PANi-PVS and PANi-PSS where an ascorbate radical anion intermediate might be present for the later composite. The excellent electroanalytical properties shown by the modified PANi films were applied to real systems. PANi-PSS microelectrodes were used as amperometric sensors for AA in low volume of human plasma. PANi-PVS elliptical needle type microelectrodes were successfully applied for the detection of ascorbate in the substomatal cavities of Barley leaves.
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Published date: 2007
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Local EPrints ID: 466312
URI: http://eprints.soton.ac.uk/id/eprint/466312
PURE UUID: 5618a63d-4690-4bb7-b7d6-b5f315c4c757
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Date deposited: 05 Jul 2022 05:10
Last modified: 16 Mar 2024 20:37
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Author:
Alejandro Martinez-Bonastre
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