Polyethyleneimine-Protected Ag_2S Quantum Dots for Near-Infrared Fluorescence-Enhanced Detection of Trace-Level Hg~(2+) in Water

摘要

In this work, we have developed a near-infrared emissive polyethyleneimine capped Ag_2(PEI-Ag_2S QD) quantum dots based chemosensor for sensing trace-level Hg~(2+) in water by taking advantage of the metal-induced aggregation strategy. The fluorescence determination of Hg~(2+) by PEI-Ag_2S QD at different pH (pH 4, 7, and 10) were performed, respectively. Under the optimum conditions, the selectivity of this system for Hg~(2+) over other metal ions in aqueous solutions was remarkably high, and its detection limits was 0.5 nM at pH 4. In addition, the present approach provides the advantages of rapidity, simplicity, low background and low cost. The assay also offers great potential for specific detection of Hg~(2+) in real water samples. This developed PEI-Ag_2S QD-based method presages more opportunities for application in environmental systems.