Surface Modification of Gold by Quercetin Monolayer for the Electrochemical Determination of Copper(II)

• Published in: Electroanalysis (New York, N.Y.) N.Y.), 2008-08, Vol.20 (15), p.1690-1695
• Main Authors: Xu, Guang-Ri, Yuan, Yong, Kim, Sunghyun, Lee, Jae-Joon
• Format: Article
• Language: English
• Subjects: Cu2+ determination; Quercetin; Surface modification; Surface regeneration
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.200804236

A quercetin monolayer has been prepared on top of the self‐assembled 3‐mercaptopropionic acid (MPA) layer for the copper ion determination. Cu2+ ions are readily accumulated on this modified electrode through the complex formation and electrochemically detected. With a quercetin layer, the redox process of Cu2+ became more reversible than at the MPA‐modified electrode. Complexation sites in MPA and quercetin were occupied within five min when the electrode was immersed in 10 μM Cu2+ solution. The MPA and quercetin layers were stable enough to allow repeated EDTA treatment to remove adsorbed Cu2+ for the surface regeneration. Only 7% decrease was found after ten times regeneration and use. Linear current response was found over the concentration range of 1 nM and 10 μM with detection limit of 0.1 nM. Common interfering ions such as Cd2+, Zn2+, and Fe2+/3+ did not show any electrochemical response in the potential range of Cu2+ determination.