Sensitive and selective determination of Cu 2+ by electrochemiluminescence of CdTe quantum dots

Abstract

For the first time, we report a sensitive and selective method to detect Cu 2+ 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 Cu 2+. The displacement of MSA capping layer created imperfections on the CdTe QDs surface, and eventually led to the ECL quenching. The quenching effect of Cu 2+ 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 Cu 2+. With the proposed method, the concentration of Cu 2+ could be detected in the range of sub-nanomolar to micromolar levels.