A new naphthalimide-picolinohydrazide derived fluorescent “turn-on” probe for hypersensitive detection of Al3+ ions and applications of real water analysis and bio-imaging

The development of high-selective chemosensors for trace Al3+ detection in the ecosystem is crucially importance due to its detrimental effects. In this work, a simple Schiff-base fluorescent probe NPP derived from naphthalimide and picolinohydrazide was rationally designed and prepared for efficient detection of Al3+. NPP exhibited prominent sensing behaviors toward Al3+ with low detection limit (LOD) (39 nM), rapid response time (1 min), strong binding affinity (4.02 × 104), good anti-interference characteristics and visual detection. Binding ratio of NPP-Al3+ complex was determined to be 1:1 by Job's plot analysis. In addition, the chelation mechanism of NPP with Al3+ ions was proposed and substantiated by the density functional theory (DFT) and time-dependent density functional theory (TD-DFT), IR spectrum and 1H NMR titration experiments. Furthermore, this "signal-on" probe NPP was efficiently utilized as a promising indicator for Al3+ detection in environmental and biological samples.