A hydrothermal method was applied to the synthesis of green-emitting gold nanoclusters (Au NCs) which are shown to be viable fluorescent probes for 4-nitrophenol (4-NP). The Au NCs were prepared by using thiol-β-cyclodextrin as a template. Under 365 nm excitation, their green fluorescence has a peak at 502 nm, with a narrow emission bandwidth of only 30 nm. The fluorescence and composition of the Au NCs were characterized and the mechanism of the nanocluster formation is discussed. Due to host-guest recognition of β-cyclodextrin and 4-NP, fluorescence is quenched. The probe can selectively recognize 4-NP among other nitrophenols. A fluorometric and colorimetric assay was developed for 4-NP that works in the 0.1 to 100 μM concentration range and has a detection limit of 90 nM (at 3σ). Graphical abstract Schematic representation of hydrothermal synthesis of green-emitting gold nanoclusters using thiol-β-cyclodextrin. Fluorescence is quenched and the absorption of the nanoclusters is increases in the presence of 4-nitrophenol.

中文翻译：

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一锅法合成发绿光的金纳米团簇作为荧光探针测定 4-硝基苯酚

水热法用于合成发绿光的金纳米团簇 (Au NCs)，该团簇被证明是 4-硝基苯酚 (4-NP) 的可行荧光探针。以硫醇-β-环糊精为模板制备了Au NCs。在 365 nm 激发下，它们的绿色荧光在 502 nm 处有一个峰值，发射带宽仅为 30 nm。表征了Au NCs的荧光和组成，并讨论了纳米团簇形成的机制。由于 β-环糊精和 4-NP 的主客体识别，荧光被淬灭。该探针可以选择性地识别其他硝基苯酚中的 4-NP。为 4-NP 开发了一种荧光和比色分析，其在 0.1 到 100 μM 的浓度范围内工作，检测限为 90 nM（3σ）。图形摘要 使用硫醇-β-环糊精水热合成发绿光的金纳米团簇的示意图。在 4-硝基苯酚的存在下，荧光被淬灭并且纳米团簇的吸收增加。