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Dopamine Oxidation at Per(6‐deoxy‐6‐thio)‐α‐Cyclodextrin Monolayer Modified Gold Electrodes
Author(s) -
Majewska Urszula E.,
Chmurski Kazimierz,
Biesiada Krzysztof,
Olszyna Andrzej R.,
Bilewicz Renata
Publication year - 2006
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.200603556
Subject(s) - dopamine , electrode , chemistry , monolayer , electrochemistry , cyclodextrin , organic chemistry , biochemistry , neuroscience , biology
The gold electrode is functionalized by sequential self‐assembly of a monolayer of the title thiolated cyclodextrin with and without dopamine included in the cavities. The structure of α‐cyclodextrin modified gold electrode is carefully characterized using STM and AFM. Surface complexation of dopamine is examined and its association constant is evaluated. Chemical reactions accompanying the electrode process of dopamine, which interfere in the electrochemical dopamine determination, are described and the conditions to avoid them are proposed. Dopamine incorporated in the α‐cyclodextrin sites anchored to the electrode surface was found to provide electrochemical contact of the electrode with the solution‐resident dopamine. Dopamine present in the α‐cyclodextrin cavities has different properties compared to dopamine in the bulk buffer solution and can act as a mediator for the dopamine molecules diffusing to the electrode. This unique mediation effect leads to improvement of the sensitivity of dopamine determination using the α‐cyclodextrin modified electrode and a procedure for the determination of dopamine in large excess of ascorbate is proposed.