Fluorescence Quenching-Based Detection of Aluminum(III): A Water-Compatible Schiff Base Sensor Approach.

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Aluminum ion (Al(III)) is crucial in biological processes but toxic at high levels.
• Selective and sensitive detection methods for Al(III) in aqueous environments are needed.
• Schiff base compounds offer potential as chemosensors due to their tunable electronic properties.

Purpose of the Study:

• To synthesize and characterize a novel Schiff base sensor (S1) for selective Al(III) detection.
• To investigate the sensing mechanism and performance of S1 in aqueous media.
• To evaluate the practical applicability of S1 for Al(III) sensing in real water samples.

Main Methods:

• Synthesis and characterization of Schiff base sensor S1.
• UV-Vis absorption and fluorescence spectroscopy for sensing studies.
• Colorimetric and fluorometric titrations to determine sensor performance.
• Analysis of binding stoichiometry, constants, and limit of detection.
• Real sample analysis using ground water and tap water.

Main Results:

• Sensor S1 exhibited a visible color change from yellow to orange upon Al(III) addition.
• UV-Vis spectra showed a bathochromic shift of 71 nm (415 to 486 nm).
• Fluorescence quenching efficiency of 82.5% was observed for Al(III) detection.
• Limit of detection (LOD) was determined to be 3.26 × 10⁻⁷ M with a 1:1 binding ratio.
• High binding (Kₐ = 6.10 × 10⁴ M⁻¹) and Stern-Volmer (K<0xE2><0x82><0x9B><0xE1><0xB5><0xA3> = 4.82 × 10⁶ M⁻¹) constants indicated strong affinity.
• Successful implementation in real water samples (ground and tap water).

Conclusions:

• The synthesized Schiff base sensor S1 is highly selective and sensitive for Al(III) detection.
• S1 functions as an effective "off"-type fluorescent probe under near-neutral pH.
• The sensor demonstrates potential for practical Al(III) monitoring in environmental water sources.