Interfacing water soluble nanomaterials with fluorescence chemosensing: Graphene quantum dot to detect Hg2+ in 100% aqueous solution

Preparation of graphene quantum dots based core-satellite hybrid spheres and their use as the ratiometric fluorescence probe for visual determination of mercury(II) ions

“…Hg 2þ is considered to be particularly effective to quench the fluorescence of GQDs obtained by the acitric acid pyrolysis reaction [37]. As expected, the fluorescence emission at 465 nm contributed by the coated GQDs on silica surface was quenched completely upon the addition of 50 mM Hg 2þ , whereas the emission at 650 nm contributed by the encapsulated CdTe QDs still remained unchanged (Fig.…”

“…Unlike traditional semiconductor QDs, GQDs possess superior properties like good biocompatibility, excellent solubility, high electrical conductivity, low toxicity, stable fluorescence, and easy labeling, thus making them at the center of significant research fields like catalysis, optoelectronic devices, biosensors and bioimaging [32,33]. However, the practical implementation of GQDs in sensing applications is still in its initial stages: only a few single emission sensors in the form of signal-off and signal-off-on modes based on energy transfer [32,34], charge transfer [35,36] or other mechanisms [37e40] have been reported for protein kinase [32], monosaccharides [35], glucose [39], trinitrotoluene [34], Hg 2þ [36,37], free chlorine [38], phosphate [40]. Due to the aforementioned disadvantages of the single emission-based fluorescent sensors and the potential toxicity of the exposed Cd-based QDs, design and synthesis of the GQDs-based non-toxic ratiometric fluorescence probe for onsite naked eye determination applications is of great significance.…”

Nanoscale Fluorescence Emitters

“…It was shown that reversible binding of mercury ion results in dramatic fl uorescence quenching in unmodifi ed G-dots and this effect was suggested for determining mercury in test media (Chakraborti et al 2013 ). Since these ions exhibit stronger affi nity to thiols, the substituting of the bound mercury ion restoring the fl uorescence was applied for determining biothiols (Zhou et al 2012b ).…”

Sensitivity to Heavy-Metal Ions of Cage-Opening Fullerene Quantum Dots

“…Most importantly, some recent studies [4][5][6][7] have demonstrated that the PL intensity is significantly quenched in the presence of certain heavy-metal ions (Hg 2+ , Fe 2+ , Cu 2+ , Pb 2+ ), thus triggering the interest of researchers in view of fast and cheap sensors for these elements.…”