Compact device prototype for turn-on fluorescence detection of sarin based on reactive 4,4-diaryloxy-BODIPY derivatives†

Development of fluorescence indicators for efficient and accurate detection of lethal nerve agents has evoked extensive interest recently. Herein, we presented two spiranic 4,4-diaryloxy-BODIPY derivatives for efficient and fluorescence turn-on detection of sarin in solution media. A colorimetric mode featured the merits of obvious color changes from dark to greenish fluorescence under UV light. The generated new fluorescence emissions reached their maxima within several minutes and the peaks were assigned to the generated by-product oxo-BDP with a fluorescence quantum yield (Φ_F) ∼ 20% in acetonitrile. The detection limits of two 4,4-diaryloxy-BODIPYs for a simulant diethylchlorophosphate (DCP) were determined to be 13.2 nM and 8.2 nM, respectively. The underlying sensing mechanism was clarified as the synergistic effect of 4,4-bond cleaving and fluorescence turn-on related to the photoinduced electron transfer process. Furthermore, a compact tubular sensor and a sensing platform prototype were fabricated properly. Superior detection results and further evaluation for real samples and simulants could be conducted at the sub-mM level on-site. Successful trials aid in understanding the structure–function relationship of 4,4-disubstituted BODIPY chromophores as well as the future development of a miniaturized device prototype for on-site detection of chemical warfare agents.