Electrochemiluminescence of CdTe quantum dots capped with glutathione and thioglycolic acid and its sensing of pb2+

Water-soluble and stable CdTe quantum dots (QDs) capped with glutathione (GSH) and thioglycolic acid (TGA) were synthesized (denoted as GSH-TGA-CdTe) and the electrochemiluminescence (ECL) behavior of the QDs was investigated. As a result of specific interaction between the GSH and Pb2+, the ECL of the QDs was selectively reduced in the presence of Pb2+. Due to the low ECL intensity of QDs capped with GSH alone, TGA as another capping agent was introduced to improve the sensitivity. On the basis of the quenching effect on the ECL of GSH-TGA-CdTe QDs, a sensitive and selective method for the determination of Pb2+ was developed and a detection limit of 0.26 nM was obtained, which was lower than previous report.