Two water-soluble compounds based on a coumarin–pyridinium scaffold were synthesized for rapid and selective detection of sulfite. The detection strategy is possible through a Michael addition reaction of the sulfite to the cyano-vinyl double bond, distinguishable through the hypsochromic shifts in absorption and emission maxima. The probes exhibited high selectivity for sulfite, with a detection limit of 1.47 μM for dye 1 and 2.8 μM for dye 2 and a near instant response time of 10–20 seconds over other analytes and reactive sulfur species. Importantly, the probes also exhibit a robust colorimetric response in the presence of sulfite. Cellular imaging studies have demonstrated that the probes are non-toxic and suitable for the detection of sulfite levels in cells. Additionally, the probes have demonstrated sensitivity to detect endogenous sulfite levels in hepatic cancer cells.

中文翻译：

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用于在水和细胞环境中快速选择性检测SO ₂衍生物的阳离子红色探针†

合成了两种基于香豆素-吡啶骨架的水溶性化合物，用于快速，选择性地检测亚硫酸盐。通过亚硫酸盐与氰基-乙烯基双键的迈克尔加成反应可以实现检测策略，这可以通过吸收和发射最大值的七色移来区分。探针对亚硫酸盐具有高选择性，染料1的检测限为1.47μM，染料2的检测限为2.8μM对其他分析物和活性硫物种的响应时间接近10-20秒。重要的是，在亚硫酸盐存在下，探针还表现出强大的比色响应。细胞成像研究表明，该探针无毒，适合检测细胞中的亚硫酸盐水平。此外，该探针已显示出检测肝癌细胞中内源性亚硫酸盐水平的敏感性。