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

Graphene quantum dots (GQDs) have successfully been utilized as efficient nano-sized fluorescence chemosensor to detect selectively Hg2+ in 100% aqueous solution (pH 7). The selectivity and sensitivity of the probe have been investigated by employing a number of spectroscopic techniques. The probe follows a ‘turn-off’ mechanism while sensing the highly toxic pollutant Hg2+. Steady state and time-resolved spectroscopic studies ensure that the adsorption of Hg2+ onto the surface of GQDs leads to the change in electronic structure of the probe which ultimately results in the quenching of fluorescence of GQDs. The capability of GQDs to detect Hg2+ under physiological conditions makes them interesting and useful sensing devices for biological applications. [Display omitted] ► Graphene quantum dots (GQDs) as efficient sensor for highly toxic mercury ions. ► The probe works in aqueous solution at physiological conditions. ► Detection process follows fluorescence ‘turn-off’ mechanism. ► Fluorescence quenching is due to the perturbation in the electronic structure of GQD as a result of adsorption of Hg2+ onto its surface.