The development of fluorescent probes for the sensitive and selective determination of highly toxic thiophenols is considerably important in the fields of biological and environmental sciences. Herein, a turn-on fluorescent probe for thiophenol, named MCSH, was constructed based on a pK_a shift mechanism, employing merocyanine dye as the fluorophore and 2,-4-dinitrobenzenesulfonamide (DNBS) group as the recognition unit. The imine nitrogen of MCSH has a pK_a value of 4.12, which renders its non-fluorescent Schiff base form exclusively under neutral conditions. However, after reacting with thiophenols, its DNBS group was removed to afford a merocyanine dye as the final product, whose pK_a value upshifts to 8.11, and was present mainly as the fluorescent protonated Schiff base form under neutral media. Such drastic change in pK_a values leads to a significant fluorescence enhancement and can be utilized for the detection of thiophenols. The fluorescence intensity at 627 nm increases linearly with thiophenol concentration in the range of 0.2–3 μM with a detection limit of 15 nM (S/N = 3). MCSH displays high selectivity for the detection of thiophenols over a wide range of other analytes, including aliphatic thiols. Furthermore, the preliminary applications of MCSH for monitoring thiophenols in living cells and environmental have been carried out.

在生物和环境科学领域，开发用于灵敏和选择性测定高毒性硫酚的荧光探针非常重要。在此，导通为苯硫酚荧光探针，命名MCSH，基于AP构建ķ_一个换档机构，采用部花青染料作为荧光团和2，-4-dinitrobenzenesulfonamide（DNBS）基团作为所述识别单元。的亚胺氮MCSH具有p ķ_一个的4.12值，这仅仅使中性条件下其非荧光希夫碱形式。但是，与硫酚反应后，其DNBS基团被除去，得到了花青染料作为最终产物，其p K_一个值升挡至8.11，并且是目前主要作为荧光在中性介质质子化的席夫碱形式。p K _a值的这种急剧变化导致荧光显着增强，可用于检测硫酚。627 nm处的荧光强度随苯硫酚浓度在0.2–3μM范围内线性增加，检出限为15 nM（S / N = 3）。MCSH对多种其他分析物（包括脂肪族硫醇）中的硫酚检测具有高选择性。此外，已经进行了MCSH在活细胞和环境中监测苯酚的初步应用。