Abstract Measurement of Cr (VI) in environmental water samples is essential for monitoring drinking water quality and the risks of industrial waste. In this study, we report the first use of a new type of label-free carbon dot-based nanosensor for ratiometric fluorescence detection of Cr (VI) in environmental water samples. By using a simple one-pot method based on the solvothermal treatment of o-phenylenediamine, bright-yellow-emissive carbon dots (Y-CDs) were synthesized, exhibiting two emission bands centered at 430 and 560 nm under a single-wavelength excitation at 345 nm. Fluorescence intensities of the two emission bands of the as-synthesized Y-CDs were found to be simultaneously Cr (VI)-sensitive. The ratio of intensity (I560 nm/I430 nm) was linear against Cr (VI) concentrations from 0.01 to 4.5 μM at pH 6.0, and the detection limit (S/N = 3: 1) was 2.3 nM, therefore having a propensity to be a suitable ratiometric probe for sensing Cr (VI). Furthermore, the nanosensor was successfully applied to quantitatively detect Cr (VI) in environmental water samples. Compared with the majority of current ratiometric Cr (VI) sensors, this label-free CD-based ratiometric probe has low toxicity, a simple synthesis route, and excellent photostability.

中文翻译：

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一种基于无标记黄色发射碳点的纳米传感器，用于环境水样中铬 (VI) 的灵敏和选择性比率检测

摘要 环境水样中 Cr (VI) 的测量对于监测饮用水质量和工业废物风险至关重要。在这项研究中，我们报告了首次使用新型无标记碳点纳米传感器对环境水样中的 Cr (VI) 进行比率荧光检测。通过使用基于邻苯二胺的溶剂热处理的简单一锅法，合成了亮黄色发光碳点 (Y-CD)，在 430 nm 和 560 nm 的单波长激发下显示出两个发射带。 345 纳米。发现合成的 Y-CD 的两个发射带的荧光强度同时对 Cr (VI) 敏感。强度比 (I560 nm/I430 nm) 与 Cr (VI) 浓度在 pH 6.0 范围内从 0.01 到 4.5 μM 呈线性关系，并且检测限 (S/N = 3:1) 为 2.3 nM，因此具有成为检测 Cr (VI) 的合适比例探针的倾向。此外，纳米传感器已成功应用于定量检测环境水样中的 Cr (VI)。与目前大多数比率式 Cr (VI) 传感器相比，这种基于 CD 的无标记比率式探针具有低毒性、合成路线简单和优异的光稳定性。