8-Hydroxyquinoline functionalized ZnS nanoparticles capped with amine groups: A fluorescent nanosensor for the facile and sensitive detection of TNT through fluorescence resonance energy transfer

8-Hydroxyquinolines (HQs) functionalized ZnS nanoparticles (NPs) with an amine-capping layer (ZnS–NH 2 –Q NPs) were prepared by a ligand-exchange process. FT-IR, XRD , NMR, TEM and fluorescence spectrometer were used to characterize the novel ZnS–NH 2 –Q NPs. Upon the addition of 2,4,6-trinitrotoluene (TNT), the amino groups on the surface of ZnS–NH 2 –Q NPs can bind TNT molecule from solution by forming Meisenheimer complex. This complex absorbs the green part of visible light, and strongly suppresses the fluorescence emission of the ZnS–NH 2 –Q NPs through Fluorescence Resonance Energy Transfer (FRET). The observed linear fluorescence intensity response for TNT in the range of 0–1.89 μM allows the quantitative detection TNT, with a detection limit down to 10 nM.