A highly selective chemosensor for Al3+ based on 2-oxo-quinoline-3-carbaldehyde Schiff-base

A new Schiff-base ligand (1) with good fluorescence response to Al(3+), derived from 2-oxo-quinoline-3-carbaldehyde and nicotinic hydrazide, had been synthesized and investigated in this paper. Spectroscopic investigation revealed that the compound 1 exhibited a high selectivity and sensitivity toward Al(III) ions over other commonly coexisting metal ions in ethanol, and the detection limit of Al(3+) ions is at the parts per billion level. The mass spectra and Job's plot confirmed the 1:1 stoichiometry between 1 and Al(3+). Potential utilization of 1 as intracellular sensors of Al(3+) ions in human cancer (HeLa) cells was also examined by confocal fluorescence microscopy.