Zirconium-based metal-organic framework encapsulated dye molecules: An excellent sensing platform for sensitive...

Residual heavy metal ions in water pose a major hazard to ecology as well as human health, and Cu²⁺, as the most common heavy metal ion in water bodies, can cause a variety of diseases in human beings with prolonged exposure, therefore, a rational sensing platform is needed for the specific detection of Cu²⁺. In this work, based on the solvothermal method, we successfully prepared the composite UIO-66@FS by encapsulating the dye fluorescein sodium molecule (FS) with a metal-organic framework material (UIO-66). The composite material has bright fluorescence emission properties with a fluorescence quantum yield of 62.03 %, and the composite material has been used to construct a fluorescence sensing platform for detecting the heavy metal Cu²⁺ in the aqueous environment. The fluorescence of UIO-66@FS can be greatly quenched by Cu²⁺, which is visible to the naked eye under UV lamp. The sensing platform is able to withstand environmental interference and has the advantages of high selectivity, excellent sensitivity, fast response, wide linear range (2.5 µM-500 µM), and low detection limit (0.246 µM) in the fluorescence quenching detection of Cu²⁺. In addition, the sensor has been used to detect Cu²⁺ in real water samples with satisfactory recoveries. Therefore, this sensing probe can be an excellent candidate for Cu²⁺ detection and has wonderful potential for real water sample detection.