Rapid and Efficient Dual Detection Of Zn²⁺ Ions and Oxytetracycline Hydrochloride Using a Responsive Fluorescent “On‐Off” Sensor Based on Simple Salen‐Type Schiff Base Ligand

This research has progressed to an effective detection chemosensor of zinc, aluminum ions and oxytetracycline hydrochloride antibiotic based on the fluorescence technique. A straightforward method utilizing microwave irradiation was employed to synthesize the salen-type Schiff base ligand N,N'-bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H₂I), providing a good 70 % yield. In ethanol, the H₂I sensor demonstrated remarkable rapidity, selectivity, and sensitivity in detecting zinc ions. The fluorescence spectrum exhibited a 44-fold substantial enhancement at 522 nm and achieved a low limit of detection (LOD) of 1.47 μM. Furthermore, the H₂I probe's emission intensity increased by 124 times when compared to the ligand's ability to detect Al³⁺ ions at 494 nm with a LOD value of 7.4 μM. Additional research was done using the H₂I probe's effective Zn²⁺ detection capability. The ability to recognize zinc ions in different real water samples demonstrated a recovery rate of 98.67 % to 103.31 %. Interestingly, a naked-eye visible fluorescence color of H₂I solution impregnated filter papers turned colorless into yell ow under UV irradiation by adding Zn²⁺ ions, renders it suitable for developing a practical zinc ion detection kit test. In particular, the I-Zn²⁺ complex effectively quenched the fluorescence toward oxytetracycline hydrochloride (OTC) with a LOD value of 1.49×10^-2 μM in DMSO:H₂O (6 : 4, v/v). This is a novel and effective procedure for sensing OTC antibiotic by the I-Zn²⁺ complex. These findings hold immense potential for the development of dual fluorescent probes, thereby enhancing sensitivity and specificity in identifying metal ions and antibiotics in a wide range of applications.