A lantern-shaped fluorescent probe based on viologen/polyoxometalate for the detection of Ag in beverages and daily necessities.

A lantern-shaped viologen/polyoxometalate (POM)-based compound [Ni(MSBP)(HO)]·(β-MoO)·HO (Ni-POM) (MSBP = 1-(4-Methanesulfonyl-benzyl)-[4,4']bipyridinyl-1-ium) was successfully synthesized by a hydrothermal method for the efficient detection of Ag. A strong affinity between Ag and SO in the viologen component of the Ni-POM structure made them interact, which led to blue fluorescence quenching. In the concentration range of 0.1-4 μM, a strong linear relationship was observed between the Agconcentration and the fluorescence intensity ratio of Ni-POM, and the limit of detection (LOD) was 20.4 nM. Considering the widespread presence of Ag in various water sources, daily necessities and food preservatives, the utilization of Ni-POM for detecting the concentration of Ag in real samples (water, daily necessities and beverages) was proved to be highly effective. Moreover, a remarkable recovery rate ranging from 95.70 % to 103.60 % was achieved, indicating that the monitoring results of practical samples were satisfactory. A fluorescent ink based on Ni-POM was designed for the purpose of information confidentiality. More importantly, the hydrogel intelligent device for visual detection of Ag was developed, which could realize visual real-time on-site quantitative detection of Ag concentration in beverages and daily necessities. Therefore, Ni-POM provides an effective platform for the development of visually quantitative detection of Ag in food and daily necessities.