A highly sensitively "off-on-off" fluorescence probe for detection of aluminum ion and water as well as application in Chinese Baijiu.

Developing highly sensitive fluorescent probe for Al and HO detection is highly desirable, due to aluminum toxicity poses a significant threat to public health. On the other hand, the determination of water content holds immense significance in a wide range of fields such as food processing, pharmaceutical manufacturing. In this paper, a novel acylhydrazone-based fluorescent probe P was successfully synthesized and characterized for the sequential detection of Al and water in alcohols. The probe P exhibited a remarkable "turn-on" response towards Al by emitting yellow fluorescence at 567 nm, with high selectivity and large Stokes shift (147 nm). Meanwhile, the in situ formed P-Al complex demonstrated significant solvatofluorochromic characteristic, which could be utilized as a second probe for detecting water via fluorescence quenching with low detection limit in alcohols (0.008%, methanol; 0.013%, ethanol; 0.013%, isopropanol; 0.037%, n-butanol; vol.%) and acetonitrile (0.072%, vol.%). Moreover, the P-Al complex was able to detect the alcoholic strength of Chinese Baijiu without the interference of other alcohols, providing an excellent recovery rate (100.0-107.0%). Different Chinese Baijius, with various alcoholic strength, could be distinguished by simple test strips. Furthermore, the P-Al complex could also analyze the water content in organic solvents .