Sensitive and selective determination of Cu2+ by electrochemiluminescence of CdTe quantum dots

For the first time, we report a sensitive and selective method to detect Cu2+ based on the electrochemiluminescence quenching of CdTe quantum dots (QDs) in aqueous solution. The mercaptosuccinic acid (MSA) protected CdTe QDs were prepared and characterized with UV, fluorescence and ECL. The anodic ECL quenching mechanism was attributed to the fact that MSA capping was removed from the surface of the CdTe QDs and preferentially bound with Cu2+. The displacement of MSA capping layer created imperfections on the CdTe QDs surface, and eventually led to the ECL quenching. The quenching effect of Cu2+ on the anodic ECL of CdTe QDs was found to be selective and concentration dependent, so we applied it to develop a method for the sensitive and selective detection of Cu2+. With the proposed method, the con centration of Cu2+ could be detected in the range of sub-nanomolar to micromolar levels. (c) 2008 Elsevier B.V. All rights reserved.