Fluorescent Nanohybrid of Gold Nanoclusters and Quantum Dots for Visual Determination of Lead Ions

Abstract

Highly green emissive gold nanoclusters (Au NCs) are synthesized using glutathione as a stabilizing agent and mercaptopropionic acid as a ligand, and the intensity of fluorescence is specifically sensitive to lead ions. We then fabricated a ratiometric fluorescence nanohybrid by covalently linking the green Au NCs to the surface of silica nanoparticles embedded with red quantum dots (QDs) for on-site visual determination of lead ions. The green fluorescence can be selectively quenched by lead ions, whereas the red fluorescence is inert to lead ions as internal reference. The different response of the two emissions results in a continuous fluorescence color change from green to yellow that can be clearly observed by the naked eyes. The nanohybrid sensor exhibits high sensitivity to lead ions with a detection limit of 3.5 nM and has been demonstrated for determination of lead ions in real water samples including tap water, mineral water, groundwater, and seawater. For practical application, we dope the Au NCs in poly(vinyl alcohol) (PVA) film and fabricate fluorescence test strips to directly detect lead ions in water. The PVA-film method has a visual detection limit of 0.1 μM, showing its promising application for on-site identification of lead ions without the need for elaborate equipment.

Fluorescent nanoprobes for sensing and imaging of metal ions: Recent advances and future perspectives

“…The detection limits for Pb 2+ and Cu 2+ were 0.2 and 0.5 nM, which was a 50- and 70-fold improvement over those methods based on dye molecules. Similarly, sensing methods using QD-based FRET were also applied in the detection of Hg 2+ [92], Pb 2+ [217], Ag + [218], Mg 2+ [78], and Ca 2+ [219]. …”

A molecular imprinting-based turn-on Ratiometric fluorescence sensor for highly selective and sensitive detection of 2,4-dichlorophenoxyacetic acid (2,4-D)

“…On the other hand, fluorescent detection has attracted a great deal of interest for various chemically, environmentally, and biologically significant species such as 2,4-D (Vinayaka et al, 2009), owing to the capabilities of high sensitivity and convenience (Geng et al, 2010;Vinayaka et al, 2009;Yu et al, 2015;Zhang et al, 2015a;Zhu et al, 2014). It is considered to be an efficient way to develop MIP-based fluorescence sensors, which will combine the advantages of high selectivity of MIPs recognition and high sensitivity of fluorescence detection (Vinayaka et al, 2009;Wu et al, 2015;Zhang et al, 2015b).…”

Selective and sensitive chemosensor for lead ions using fluorescent carbon dots prepared from chocolate by one-step hydrothermal method

“…Lead, one of the most common toxic heavy metals, is widely used in pigments, water pipes, storage batteries, anticorrosion coatings, alloys, etc and spreads in different areas of the environment by all ways. Meanwhile, Pb 2+ is very easily accumulated in human nervous and cardiovascular systems when exposed to contaminated air and water sources owing to its non-biodegradability [4,5]. When the concentration of Pb 2+ is higher than 5 µM in blood, it can lead to anemia, reproductive dysfunction, nervous system dysfunction and developmental disorders, etc.…”