The novel ratiometric fluorescent probe HPQRB with an ESIPT effect based on Michael addition for highly sensitive and fast detection of sulfite in living HepG2 cells is reported. HPQRB can be easily synthesized by a two‐step condensation reaction. HPQRB has a large emission shift (Δλ=116 nm), which is beneficial for fluorescence imaging research, and its sulfite‐responsive site is based on a rhodamine‐like structure with the emission peak at 566 nm, which decreases with increasing sulfite concentration. and its HPQ structure always has an ESIPT effect throughout the reaction process, keeping the emission peak at 450 nm as a self‐reference. In particular, HPQRB has high selectivity for sulfite and responds quickly (within 30 s) with a low detection limit (44 nM). Furthermore, HPQRB has been successfully used for fluorescence imaging of sulfite in HepG2 cells, demonstrating the superior ability to detect sulfite under physiological conditions.

中文翻译：

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基于 ESIPT 的比例荧光探针，用于高灵敏度、快速检测活细胞中的亚硫酸盐。

据报道，新型比率荧光探针 HPQRB 具有基于 Michael 加成的 ESIPT 效应，可高灵敏度、快速检测活 HepG2 细胞中的亚硫酸盐。HPQRB可以通过两步缩合反应轻松合成。HPQRB具有较大的发射位移（Δλ = 116 nm），有利于荧光成像研究，其亚硫酸盐响应位点基于类罗丹明结构，发射峰位于566 nm，随着亚硫酸盐浓度的增加而降低。其HPQ结构在整个反应过程中始终具有ESIPT效应，将发射峰保持在450 nm处作为自参考。特别是，HPQRB 对亚硫酸盐具有高选择性，响应快（30 秒内），检测限低 (44 nM)。此外，HPQRB 已成功用于 HepG2 细胞中亚硫酸盐的荧光成像，证明了在生理条件下检测亚硫酸盐的卓越能力。