A highly selective colorimetric and fluorescent chemosensor for Al(III) based-on simple naphthol in aqueous solution

Area of Science:

• Analytical Chemistry
• Materials Science
• Inorganic Chemistry

Background:

• Aluminum ions (Al(3+)) play crucial roles in biological processes but can be toxic at elevated levels.
• Developing selective and sensitive methods for Al(3+) detection is vital for environmental and biomedical applications.
• Existing chemosensors often face limitations in sensitivity, selectivity, or operational simplicity.

Purpose of the Study:

• To synthesize and characterize a novel chemosensor, designated as L.
• To evaluate the efficacy of L as both a colorimetric and fluorescent probe for Al(3+) detection.
• To determine the binding stoichiometry, affinity, and site of interaction between L and Al(3+).

Main Methods:

• Synthesis and full characterization of the chemosensor L.
• Colorimetric and fluorescence spectroscopy for Al(3+) detection.
• Job plot analysis (UV-Vis and fluorescence) and MALDI-TOF MS to determine binding stoichiometry.
• Benesi-Hildebrand plot analysis to calculate binding constants.
• (1)H NMR titration experiments to identify the binding site.

Main Results:

• Successful synthesis and characterization of chemosensor L.
• L exhibited sensitive colorimetric and fluorescent responses to Al(3+) ions.
• A low detection limit of 8.87×10(-7) M was achieved in a CH3CN-H2O solution.
• The binding stoichiometry of L to Al(3+) was confirmed as 1:1.
• A binding constant (Ka) of 4.8×10(5) M(-1) and the binding site were determined.

Conclusions:

• The developed chemosensor L is effective for the selective and sensitive detection of Al(3+) ions.
• The dual-mode (colorimetric and fluorescent) detection capability enhances its utility.
• The quantitative data on binding affinity and stoichiometry provide a foundation for further sensor development and application.