Detection of Trace Amounts of Fe3+ and Cr6+ Ions Using a ZIF‑8 Fluorescent Sensor with High Selectivity and Fast Response

چکیده مقاله

While zeolitic imidazole framework (ZIF)-based materials have shown promising metal ion detection performances, they did
not achieve the same results as for pure ZIFs. Here, a highly porous ZIF-8 material is synthesized using a chemical method
under stirring at room temperature, and characterized in terms of crystallinity and chemical state. The resulting ZIF-8 is
employed as a multifunctional fluorescent sensor to detect Fe3+
and Cr6+
metal ions dissolved in water, exhibiting high
luminescence with a broad wavelength band in the visible light region. The water-soluble metal ions are found to be very
sensitive to a decrease in the luminescence intensity of ZIF-8, and can be detected at trace amounts with high selectivity.
The detection limits of Fe3+
and Cr6+
ions are achieved to be 2.1 × 10–
6 and 7.6 × 10–
7 M, respectively. The intensity of luminescence
decreases with increasing the concentration of both metal ions, thereby giving rise to the complete fluo>rescence
quenching with a very fast response time using Fe3+
and Cr6+
ion concentrations higher than 1.0 × 10–
4 and 4.7 × 10–
5 M,
respectively. These results may pave the way for the utilization of pure ZIF materials in the