Carbon dots–cadmium sulfide quantum dots nanocomposite for ‘on–off’ fluorescence sensing of chromium(vi) ions

This work involves fluorescent probe which is composed of carbon dots (CD) and cadmium sulfide quantum dots (CdS QD) for the sensitive and selective fluorescence detection of chromium(vi) ions. The blue fluorescent carbon dots were synthesized by hydrothermal method from natural precursor apricot. The carbon dots-cadmium sulfide quantum dots (CD-CdS QD) nanocomposite was synthesized and all as-synthesized products were characterized using different characterization techniques. It showed white fluorescence under UV light which was quenched selectively in the presence of chromium(vi) ions due to the inner filter effect (IFE). The linear decrease in the white fluorescence was observed in the concentration range 2-120 μM of chromium(vi) ions with the limit of detection 2.07 μM. This is novel probe for the sensitive, selective and rapid detection of chromium(vi) ions.