Abstract A novel colorimetric sensor based on red-emitting bovine serum albumin‑golden nanoclusters (BSA-AuNCs) and green-colored fluorescein that exhibited traffic light-type color change was developed for ratiometric and visual detection of mercury (Hg). In the presence of Hg2+, the red fluorescence from BSA-AuNCs was quenched while the green fluorescein was inert thus as a reference. And it presented traffic light-type (red, yellow and green) color in the low, middle and high concentration of Hg2+. A potential mechanism was investigated by Energy Dispersive Spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). The selective quenching mechanism may be due to the formation of gold amalgam bonds between BSA-AuNCs and Hg2+. A linear correlation was constructed for Hg2+ in the concentration range of 10–500 μg L−1. A limit of detection (LOD) of 7.4 μg L−1 and a relative standard deviation (RSD, n = 7) of 0.4% were obtained, which can be used to monitor the concentration of Hg2+. In visual detection, as low as 0.1 μg mL−1 of Hg2+ can be easily discriminated from the blank with the naked eye. The proposed method was validated by analysis of certified environment and food samples with satisfactory results.

中文翻译：

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通过混合荧光素的金色纳米团簇对汞的交通灯型灵敏视觉检测

摘要 基于发红光的牛血清白蛋白-金纳米团簇 (BSA-AuNCs) 和绿色荧光素，开发了一种新型比色传感器，该传感器具有交通灯型颜色变化，用于汞 (Hg) 的比率和视觉检测。在 Hg2+ 存在下，来自 BSA-AuNCs 的红色荧光被淬灭，而绿色荧光素呈惰性，因此作为参考。并在低、中、高浓度的Hg2+中呈现交通灯型（红、黄、绿）色。通过能谱仪 (EDS) 和 X 射线光电子能谱仪 (XPS) 研究了潜在的机制。选择性淬灭机制可能是由于 BSA-AuNCs 和 Hg2+ 之间形成了金汞合金键。在 10–500 μg L-1 的浓度范围内构建了 Hg2+ 的线性相关性。获得了 7.4 μg L-1 的检测限 (LOD) 和 0.4% 的相对标准偏差（RSD，n = 7），可用于监测 Hg2+ 的浓度。在视觉检测中，低至 0.1 μg mL-1 的 Hg2+ 可以很容易地用肉眼与空白区分开来。所提出的方法通过对认证环境和食品样品的分析得到了验证，结果令人满意。