Novel amino-functionalized MOF-based sensor for zinc ion detection in water and blood serum samples

Aquatic systems with low zinc levels can experience a significant decrease in carbon dioxide uptake and limited growth of phytoplankton species. In this study, we describe the use of a new fluorescent sensor based on NH₂-MIL-53(Al), and modified with glutaraldehyde and sulfadoxine, for selectively detecting zinc ions in water and blood serum samples. Characterization of the synthesized material was performed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), confirming successful functionalization and preservation of the MOF structure. The sensor's performance for Zn²⁺ detection was evaluated by spectrofluorometry, demonstrating a significant fluorescence enhancement upon Zn²⁺ binding due to the interaction between Zn²⁺ ions and the sulfonamide groups. With a detection limit as low as 3.14 × 10^-2 ppm, the sensor demonstrates high selectivity for Zn²⁺ over other common metal ions. The sensor's response is rapid, stable, and reproducible, making it suitable for practical applications. Real sample analysis was conducted in tap water and blood serum samples, with the results compared to those obtained using ICP-OES and a colorimetric test with 5-bromo-PAPS. The comparison confirmed the high accuracy and reliability of the fluorescent sensor in detecting Zn²⁺ ions in complex matrices. NH₂-MIL-53(Al) modified with glutaraldehyde and sulfadoxine shows potential as a selective fluorescent sensor for Zn²⁺ detection, making it a valuable tool for monitoring the environment and biology.