Sensing in 15 s for Aqueous Fluoride Anion by Water-Insoluble Fluorescent Probe Incorporating Hydrogel

Anion recognition and sensing via artificial receptors have attracted a great deal of attention since they play a fundamental and important role in chemical, biological, medical, and environmental processes. Fluoride, as one of the smallest anions, is of particular interest because of its role in dental care and the analysis of drinking water. Herein, we invented a new method for F^– detection by adopting the hydrogel as the supporter of reaction between a water insoluble fluorescent probe and F^– in the water environment. This method is highly rapid, selective, and sensitive, which can determine F^– levels in 15 s at the drinking water standard. A novel compound N-(3-(benzo­[d]­thiazol-2-yl)-4-(tert-butyldiphenylsilyloxy)­phenyl) acetamide (BTBPA) was synthesized as the fluorescent probe because of the significant fluorescent color change from blue to green after the reaction with F^–. This method does not require the probe substances to be water-soluble, which greatly expands the range of the specific fluorescent molecules used in ion detection. Additionally, just a few microliter samples were required in the analysis procedures with this method.