Ni-MOF Functionalized Carbon Dots with Fluorescence and Adsorption Performance for Rapid Detection of Fe (III) and Ascorbic Acid.

In this work, an "on-off-on" fluorescent probe based on Ni-MOF functionalized Nitrogen-doped carbon quantum dots (Ni-MOF-NCDs) was developed. Ni-MOF-NCDs was characterized by FT-IR, TEM, SEM, and XPS. The presence of Fe (III) will reduce the fluorescence intensity of Ni-MOF-NCDs and "turn off" the fluorescence signal at emission peak of 390 nm, while the signal can be "turn on" after the addition of ascorbic acid (AA). The Ni-MOF-NCDs was established as an "on-off-on" fluorescent probe for the detection of Fe (III) and AA with the linear ranges of 0.029-8.0 µg/mL and 0.263-18.0 µg/mL, respectively. The method has been successfully applied to the detection of water samples and foods with satisfactory recovery. The experimental results showed that Ni-MOF-NCDs not only had the fluorescence properties of NCDs, but also had the adsorption performance of Ni-MOF.