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Highly selective electrochemical detection of dopamine using interdigitated array electrodes modified with nafion/polyester lonomer layered film
Author(s) -
Niwa Osamu,
Morita Masao,
Tabei Hisao
Publication year - 1994
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140060310
Subject(s) - ascorbic acid , nafion , electrode , electrochemistry , cathode , microelectrode , anode , layer (electronics) , chemistry , polyester , inorganic chemistry , redox , materials science , organic chemistry , food science
Abstract The highly selective electrochemical detection of dopamine has been developed using an interdigitated microarray (IDA) electrode coated with Nafion and polyester ionomer (Kodak AQ29D) layered films. Because high redox cycling of dopamine can be maintained in the AQ29D bottom layer, a low detection limit of 50 nmol/dm 3 is obtained. Since the upper Nafion laybr prevents L ‐ascorbic acid from diffusing into the AQ29D layer, the acid concentration in this layer rapidly decreases when potentiostating one IDA electrode (anode) above and the other (cathode) below the redox potential of dopamine. This is because L ‐ascorbic acid molecules in the AQ29D layer are removed quickly by the electrochemical or electrocatalytic oxidation at the anode. On the other hand, almost all of the oxidized dopamine molecules are reduced at the cathode, which maintains a constant dopamine concentration in the film during measurement. After the potential step, the influence of L ‐ascorbic acid is almost completely eliminated within a few seconds due to the reduction in acid concentration in the modified layer. As a result, dopamine can be detected quantitatively at the cathode in the presence of 100‐fold excess of L ‐ascorbic acid.