A Novel Surface‐Tethered Double‐Signal Electrochemiluminescence Sensor Based on Luminol@Au and CdS Quantum Dots for Mercury Ion Detection

Abstract

AbstractA novel surface‐tethered double‐signals electrochemiluminescence (ECL) sensor has been developed for the detection of mercury (II) ions (Hg2+). Firstly, cysteamine functionalized CdS quantum dots (CdS QDs‐Cys) as one of ECL nanoprobes were deposited onto the glass carbon electrode. Then electrode was modified with carboxylated thymine via the carboxyl groups of thymine and amino groups of CdS QDs‐Cys. Due to the specific recognition between thymine and Hg2+, the above electrode acted as the substrate to capturing target Hg2+, which could further bind luminol@Au‐Cys‐T multifunctional nanoarchitecture. It was found that the ECL intensity of luminol and CdS QDs both increased with the increasing of mercury ion concentration. Under the optimum condition, the logarithm of the ratio of two signals was linearly proportionally to the logarithmic concentrations of Hg2+ in the range 0.005 ∼ 2.5 nM with a limit of detection of 0.002 nM (S/N=3). The novel sensor displayed good reproducibility and sensitivity and provided an alternative analytical approach for the following research.