A ratiometric fluorescence sensor based on UiO-66-CdTe@ZIF-8 core-shell nanocomposites for the highly selective detection of NO

In this work, a ratiometric fluorescence sensor based on UiO-66-CdTe@ZIF-8 core-shell nanocomposites (CSNCPs) was developed for the highly selective detection of NO. The yellow-emitting UiO-66-NH2 core was synthesised using the solvothermal method and then coated with red-emitting CdTe quantum dots (QDs). The resulting core UiO-66-CdTe nanocomposites served as the signal-displaying unit (UiO-66-CdTe). Next, the UiO-66-CdTe nanocomposite was encapsulated in a zeolitic imidazolate framework (ZIF-8), whereas large molecules such as substrate and oxidase have very little effect on its fluorescence. A detectable signal was obtained by monitoring the NO quenching fluorescence of UiO-66-NH2, and the CdTe QDs served as the reference signal. The fluorescence quenching ratio I442/I574 was proportional to the logarithm of NO concentration concentration in the range of 0-0.10 nM with the detection limit of 0.11 nM. The results demonstrate that the proposed UiO-66-CdTe@ZIF-8 CSNCPs-based sensor is suitable for quantitative purposes in various environmental and biological applications.