A “bottle-around-ship” method to encapsulated carbon nitride and CdTe quantum dots in ZIF-8 as the dual emission fluorescent probe for detection of mercury (II) ion

A facile and efficient “bottle-around-ship” approach for preparing the ratiometric fluorescent probe has been developed by encapsulating the red-colored fluorescence CdTe quantum dots (QDs) and blue-colored fluorescence graphitic carbon nitride quantum dots (g-CNQDs) into the zeolitic imidazolate metal–organic frameworks (ZIF-8) in one step. At a single excitation of 360 nm, the obtained probe ZIF-8@g-CNQD/CdTe shows the dual-emission peaked at 450 and 633 nm, respectively. The red emission of CdTe QDs is selectively quenched by the Hg 2+ , whereas the blue fluorescence of g-CNQDs as an internal reference is insensitive, resulting in an apparent color transformation from pink to blue for special recognition of Hg 2+ . By this approach, the relative fluorescence intensity ratio ( F 633 / F 450 ) decreased linearly with increasing Hg 2+ concentration in the 0.2–3.5 μM range with a low limit of detection (LOD) of ~ 46 nM. Therefore, we demonstrate that this “bottle-around-ship” process provides a new strategy for the construction of ratiometric fluorescent Hg 2+ probes with good simplicity, high efficiency, and excellent stabilities. Moreover, the obtained Hg 2+ fluorescent probe shows good results in the detection of actual samples. Graphical abstract