Synthesis and Application of Indanone-based Turn-on Probe for Mercury/Fluoride Ions in Real Samples

Two novel reactive fluorescent probes, (E)-2-(pyridin-2-ylmethylidene)-5-(phenoxycarbonothioyloxy)-2,3-dihydro-1H-indenone (TP-PMT) synthesized by introducing a phenoxycarbonyl thiosulfinate unit and (E)-2-(pyridin-2-ylmethylidene)-5-((tert-butyldimethylsilyl)oxy)-2,3-dihydro-1H-indenone (TP-TBS) synthesized by introducing a tert-butyldimethylchlorosilane recognition unit, both based on the same (E)-2-(pyridin-2-ylmethylidene)-5-hydroxy-2,3-dihydro-1H-indenone (TP-OH) structure, for highly selective and sensitive detection of mercury ions (Hg²⁺) and fluoride ions (F^-). The TP-PMT demonstrated excellent sensitivity and selectivity for Hg²⁺, showing significant fluorescence enhancement and enabling quantitative detection over the 0-22 μM range, with a low detection limit of 14.7 nM. Similarly, exposure to F^- triggered a distinct fluorescence response in TP-TBS, allowing for quantitative determination in the concentration range of 0-21 μM with a low detection limit of 3.18 nM. Both probes were successfully applied for the reliable determination of their respective target ions in real-world practical samples, demonstrating excellent precision, accuracy, and recovery.