A new colorimetric and turn-on fluorescent chemosensor for Al3+ in aqueous medium and its application in live-cell imaging

• A novel Schiff base fluorescent chemosensor HL was prepared.
• Optical absorption and emission measurements were performed.
• HL manifests selective signaling response to Al3+ in aqueous medium.
• HL is sensitive to Al3+ with detection limit of 36.6 nM.
• The application of HL for imaging of Al3+ in living cells was achieved.

A new simple Schiff-base ligand 2-Hydroxy-1-naphthaldehyde-(2-pyridyl) hydrazone (HL) was synthesized and characterized as a fluorescent probe. In aqueous solution containing 10% ethanol (Hexamethylenetetramine-HCl buffer, pH5.3), HL selectively binds Al3+to form a 1:1 ligand/metal complex, resulting in a color change from colorless to yellow–green and a significant fluorescence enhancement at 454 nm. The addition of EDTA quenches fluorescence of the HL·Al3+ complex, indicating that HL serves as a reversible chemosensor for Al3+. Under the optimum conditions, the dynamic range of the system was found to be linear up to 4.0 × 10−6 M Al3+ ions with a limit of detection of 36.6 nM. The probe is very effective for detection of intracellular Al3+ through fluorescence microscopic imaging.

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