Tan Qiren, Li Xiaoying, Wang Lumei, Zhao Jie, Yang Qinyan, Sun Peng, Deng Yun, Shen Guoqing
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.
YunNan (Dali) Research Institute of Shanghai Jiao Tong University, Dali, Yunnan, China.
Front Chem. 2022 Sep 30;10:1005231. doi: 10.3389/fchem.2022.1005231. eCollection 2022.
Cadmium (Cd) and mercury ions (Hg) are essential for the quality control of food samples because of their serious toxicity to human health, but the effective and simple strategy for their parallel detection remains challenging. In this paper, a rapid and simple parallel detection method for Cd and Hg was developed using carbon dots (CDs) as fluorescent sensors. A one-step hydrothermal method with a single precursor l-arginine as both the carbon and nitrogen sources was employed to prepare nitrogen-doped CDs (N-CDs). N-CDs exhibited a uniform particle size and excitation-independent fluorescence emission. The maximum emission wavelength of N-CDs was observed at 354 nm with the excitation wavelength at 295 nm. The quantum yield of N-CDs reached as high as 71.6% in water. By using sodium diphosphate and phytic acid as masking agents, the fluorescent sensor can be quenched by Cd and Hg in the linear range of 0-26.8 μM and 0-49.9 μM within 5 min. Other common ions in farm products showed no significant effect on the fluorescence intensity of the sensing system. The results demonstrated that the sensing system had good selectivity and sensitivity for Cd and Hg. The detection limits for Cd and Hg were 0.20 and 0.188 μM, respectively. In addition, the fluorescent sensor had been successfully applied for the detection of Cd and Hg in fruits and vegetables, and the recoveries were 86.44-109.40% and 86.62-115.32%, respectively. The proposed fluorescent sensor provides a rapid, simple, and sensitive detection method for Cd and Hg in food samples and thus a novel quantitative detection method for heavy metal ions in foods.
镉（Cd）和汞离子（Hg）因其对人体健康具有严重毒性，故而对于食品样品的质量控制至关重要，但针对它们的并行检测，有效且简便的策略仍具有挑战性。本文利用碳点（CDs）作为荧光传感器，开发了一种快速简便的Cd和Hg并行检测方法。采用一步水热法，以单一前驱体L-精氨酸作为碳源和氮源，制备了氮掺杂碳点（N-CDs）。N-CDs呈现出均匀的粒径且具有与激发无关的荧光发射。在激发波长为295 nm时，N-CDs的最大发射波长为354 nm。N-CDs在水中的量子产率高达71.6%。通过使用焦磷酸钠和植酸作为掩蔽剂，该荧光传感器可在5分钟内被0 - 26.8 μM的Cd和0 - 49.9 μM的Hg淬灭。农产品中的其他常见离子对传感系统的荧光强度无显著影响。结果表明，该传感系统对Cd和Hg具有良好的选择性和灵敏度。Cd和Hg的检测限分别为0.20和0.188 μM。此外，该荧光传感器已成功应用于水果和蔬菜中Cd和Hg的检测，回收率分别为86.44 - 109.40%和86.62 - 115.32%。所提出的荧光传感器为食品样品中Cd和Hg提供了一种快速、简便且灵敏的检测方法，从而为食品中重金属离子提供了一种新颖的定量检测方法。
