Construction of an ion-imprinted ratiometric fluorescence sensor integrating zirconium-based metal-organic framework and carbon dots for sensitive detection of copper ion.

The pollution of Cu2+ has seriously endangered human health and water ecological environment. It is crucial to explore a rapid and sensitive fluorescence detection method for monitoring Cu2+. In present work, an ion-imprinted functionalized zirconium-based metal-organic framework (NH2-UiO-66@IIPs) was innovatively designed and prepared, and yellow fluorescent carbon dots (CDs) were fabricated with o-phenylenediamine and tetraphenylethylene via a hydrothermal method. The experimental results demonstrated that Cu2+ could quench the fluorescence intensity of NH2-UiO-66@IIPs, and the fluorescence intensity of CDs remained almost unaffected. Based on this phenomenon, a novel ratiometric fluorescent sensor was constructed for efficient detection of Cu2+ in real water samples, in which blue fluorescent NH2-UiO-66@IIPs acted as a response signal and the yellow fluorescent CDs served as the reference. The sensor provided a wide linear range of 0.13 -25.43 mg/L and a detection limit of 0.027 mg/L. The sensor has been successfully applied to the detection of Cu2+ in real surface water samples with satisfactory spiked recoveries in the range of 98.0 % -104.1 %. The constructed ratiometric fluorescence sensor not only exhibited convenient and fast detection ability and expected high selectivity and sensitivity, but also provided a favorable application prospect for the detection of Cu2+ in water environment.