A multifunctional fluorescence sensor based Zn(II) metal-organic framework for rapid and sensitive detection Fe3+ and Al3+

Recognition and detection of Fe³⁺ and Al³⁺ ions in water are important for human health and life. Herein, a novel multifunctional fluorescence sensor based on zinc-based metal-organic frameworks (Zn-MOF) was developed using zinc nitrate hexahydrate and pyridine-2,5-dicarboxylic acid by solvothermal condition, and characterized by X-ray single crystal diffraction, elemental analysis, powder X-ray diffraction (PXRD), etc. The PXRD experiment results observed that the structure of Zn-MOF is rearranged after water molecules exchanged all 3 DMF solvates in the pores. Fluorescent sensing experiments revealed that Zn-MOF exhibits high sensitivity in detecting Fe³⁺ and Al³⁺ by significant fluorescence quenching. The limit of detection (LOD) of Fe³⁺ and Al³⁺ were 0.18 μM and 0.064 μM, respectively. The anti-interference experiment revealing that Zn-MOF has a high selectivity to detect Fe³⁺ and Al³⁺. In addition, the quenching mechanism of Zn-MOF was demonstrated to be attributed to the inner filter effect (IFE). Furthermore, in the real sample detection of tap water, the recoveries of Fe³⁺ and Al³⁺ were 103.0 %–107.9 % and 106.1 %–110.5 %, respectively, and the relative standard deviations (RSD) were less than 7.42 % and 6.20 %, respectively. This work provided an reliable method for the quantitative detection of Fe³⁺ and Al³⁺ and was successfully applied in tap water with satisfactory recovery and precision.