A Bifunctional “off‐on” Fluorescence Probe Based on Naphthalene for the Detection of Ag+ and Al3+ and Its Application in Practical Water Samples, As a Logic Gate and As Test Paper

A bifunctional fluorescence probe (PCT) based on 2-Hydroxy-1-naphthaldehyde and thiosemicarbazide was developed. The probe PCT can selectively detect Ag+ and Al3+ with two clear fluorescence color changes from colorless to yellow and blue violet, respectively. According to the Job's plots and mass spectrum, the binding stoichiometry of the probe PCT with Ag+ and Al3+ was 1 : 1, respectively. Moreover, the detection limit values of PCT for Ag+ and Al3+ in neutral solutions were 1.97 and 1.63 nM and these values were remarkably lower than allowed Ag+ and Al3+ concentrations in potable water determined by the World Health Organization (WHO). The distinct different binding mode were elucidated in this paper. Finally, the probe PCT has been used successfully for the detection of Ag+ and Al3+ in real water samples, logic gate and test paper.