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.

Abstract

This research has progressed a effective dual detection chemosensor of zinc ion and oxytetracycline hydrochloride antibiotic based on 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. The ability to recognize zinc ions in different real water samples demonstrated from 98.67% to 103.31% in recovery. Interestingly, a naked-eye visible fluorescence color of H2I solution impregnated filter papers turned colorless into yellow under UV irradiation by adding Zn2+ ion, 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 in 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 wide range of applications.