A versatile chemosensor for the detection of Al³⁺ and picric acid (PA) in aqueous solution

Developing chemosensors for efficient detection of Al3+ and picric acid in water is in high demand but challenging. In this paper, we have demonstrated the potential of a probe, 6,6'-(1E,1'E)-(2-hydroxypropane-1,3-diyl)bis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis(2-methoxyphenol) (H2Vm), as a "switch-on" Al3+ responsive fluorescence chemosensor in water. In addition to the ability of H2Vm to sense Al3+, the Al2-Vm2 complex offers selectivity towards picric acid (PA) in HEPES buffer (pH = 7.4) solution (detection limit (20.13 × 10-9 M) via "switch-off" mode. The reversible fluorescence response with low detection limit (11.34 × 10-9 M) in the pH range of 6.0-9.0 makes H2Vm suitable for tracking Al3+ in live HCT cells. The resulting Al2-Vm2 complex is also responsive towards PA in HCT cells. Thus, a versatile fluorescence spectroscopy-based chemosensor for Al3+ and picric acid has been developed with possible applications in human health and national security.