A Schiff Base Fluorimetric Chemosensor for Sequential Detection of Al ³⁺ and Linezolid Antibiotic: An Experimental and Theoretical Approach

ABSTRACT A Schiff Base chemosensor ( CS ) was synthesized by the condensation reaction between 2‐hydroxy‐1‐naphthaldehyde and hydrazine. The synthesized chemosensor was characterized by FT‐IR, 1 H NMR, and 13 C NMR. The sensing properties of the chemosensor were studied toward various metal ions, including Al 3+ , Mn 2+ , Cu 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Ag + , Zn 2+ , Pd 2+ , Cr 3+ , Fe 3+ , Hg 2+ , Co 2+ , and Fe 2+ . Among these metal ions, the addition of Al 3+ enhances the fluorescence intensity (FI) of CS due to the formation of the CS‐Al 3+ complex. The CS‐Al 3+ complex was further used for the detection of Linezolid (LZ) antibiotic. The introduction of LZ into the CS‐Al 3+ complex quenched the FI. Under optimum conditions, the linear range for the determination of Al 3+ was found to be 0.3–3.0 µg mL −1 . The limit of detection (LOD) and limit of quantification (LOQ) for Al 3+ were found to be 0.09 and 0.29 µg mL −1 , respectively. The linearity for the determination of LZ was in the range of 1.0–6.0 µg mL −1 . LOD and LOQ for LZ were found to be 0.29 and 0.88 µg mL −1 , respectively. In addition, a theoretical study was performed by means of density functional theory (DFT) simulation, which reveals that CS moved consistently with Al(III) through the nitrogen (1.93 Å) and oxygen (2.13 Å) sites in all complexes, establishing stable bonds with an adsorption energy of −1.90 eV and a +0.11 ev charge on Al 3+ . Furthermore, the chemosensor was applied for the determination of Al 3+ in water and LZ in serum and commercial formulation with good percent recoveries in the range of 93%–101%, respectively.