A potential masking approach in the detection of dopamine on 3-mercaptopropionic acid capped ZnSe quantum dots modified gold electrode in the presence of interferences

Electrochemical detection of dopamine in the presence of excess ascorbic acid and uric acid on a gold electrode modified with 3-mercaptopropionic acid capped zinc selenide quantum dots is presented. The synthesized quantum dots were immobilized on the surface of gold disk electrode by self assembly method in dark conditions for 24 h and electrochemically characterized. A surface coverage of 0.91 was calculated using electrochemical impedance spectroscopy. The quantum dot afforded the simultaneous detection of these three compounds with wide peak separations which allowed the interferences to be masked with applied potential. Using a potential window of 0-400 mV, where only dopamine was electroactive, a detection limit of 2.43 x 10(-10) M and 5.65 x 10(-10) M were calculated from square wave voltammetry and amperometry respectively. (C) 2010 Elsevier B.V. All rights reserved.