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A Study on Tannic Acid-doped Polypyrrole Films on Gold Electrodes for Selective Electrochemical Detection of Dopamine
Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Hunan Normal University), Ministry of Education, Hunan Normal University, Changsha 410081, PR China
* Author to whom correspondence should be addressed.
Received: 30 May 2004; Accepted: 17 September 2004 / Published: 27 April 2005
Abstract: Tannic acid-doped polypyrrole (PPY/TA) films have been grown on goldelectrodes for selective electrochemical detection of dopamine (DA). Electrochemicalquartz crystal microbalance (EQCM) studies revealed that, in vivid contrast toperchlorate-doped polypyrrole films (PPY/ClO4-), the redox switching of PPY/TA filmsin aqueous solutions involved only cation transport if the solution pH was greater than3~4. The PPY/TA Au electrodes also exhibited attractive permselectivity forelectroactive cations, namely, effectively blocking the electrochemical reactions ofanionic ferricyanide and ascorbic acid (AA) while well retaining the electrochemicalactivities of hexaammineruthenium (III) and dopamine as cationic species. A 500 HzPPY/TA film could effectively block the redox current of up to 5.0 mM AA. Thecoexistence of ascorbic acid in the measurement solution notably enhanced the currentsignal for dopamine oxidation, due probably to the chemical regeneration of dopaminethrough an ascorbic acid-catalyzed reduction of the electro-oxidation product ofdopamine (EC’ mechanism), and the greatest amplification was found at an ascorbic acidconcentration of 1.0 mM. The differential pulse voltammetry peak current for DAoxidation was linear with DA concentration in the range of 0 to 10 μM, with sensitivityof 0.125 and 0.268 μA/μM, as well as lower detection limit of 2.0 and 0.3 μM in a PBSsolution without AA and with 1.0 mM coexisting AA, respectively.
Keywords: tannic acid-doped polypyrrole; permselectivity; dopamine detection.
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Jiang, L.; Xie, Q.; Li, Z.; Li, Y.; Yao, S. A Study on Tannic Acid-doped Polypyrrole Films on Gold Electrodes for Selective Electrochemical Detection of Dopamine. Sensors 2005, 5, 199-208.
Jiang L, Xie Q, Li Z, Li Y, Yao S. A Study on Tannic Acid-doped Polypyrrole Films on Gold Electrodes for Selective Electrochemical Detection of Dopamine. Sensors. 2005; 5(4):199-208.
Jiang, Ling; Xie, Qingji; Li, Zhili; Li, Yunlong; Yao, Shouzhuo. 2005. "A Study on Tannic Acid-doped Polypyrrole Films on Gold Electrodes for Selective Electrochemical Detection of Dopamine." Sensors 5, no. 4: 199-208.