Electrochemiluminescent immunosensor based on CdS quantum dots for ultrasensitive detection of microcystin-LR

In this paper, a sandwich-type electrochemiluminescent (ECL) immunosensor for detection of microcystin-leucine-arginine (MCLR) based on gold nanoparticles (GNPs) and CdS quantum dots (QDs) was constructed. Transmission electron microscope image (TEM), photoluminescence spectra, ultraviolet-visible absorption spectra were used to characterize the CdS QDs. The fabrication processes of the immunosensor were characterized via electrochemical impedance spectra (EIS). A strong and stable ECL signal was emitted through the electron-transfer reaction between the electron-injected CdS QDs and reduced products of S2O82- in phosphate buffered solution (PBS, pH 7.4) containing of 0.1 M K2S2O8 and 0.1 M KCl. Under the optimum conditions, the ECL immunosensor possesses a wide linear response to MCLR that ranges from 0.01 to 50 mu g/L, with a low detection limit of 0.0028 mu g/L. Moreover, selectivity, stability, and reproducibility of the proposed immunosensor were acceptable. (C) 2015 Elsevier B.V. All rights reserved.