Wang Dingfeng, Gao Liwei, Liu Xinru, Wang Linfan, Zhang Ting, Guo Guoqiang, He Hongxing, Chen Da
Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, PR China.
Department of Chemical Engineering, Ningbo Polytechnic, Ningbo, Zhejiang 315800, PR China.
Food Chem. 2025 Oct 15;489:144980. doi: 10.1016/j.foodchem.2025.144980. Epub 2025 May 30.
Trace detection of nitrite in food has gained increasing attention due to its connection with biological and environmental processes. Herein, a dual-mode fluorometric/colorimetric sensor is established for nitrite detection by combining the oxidase-like activity of iron alkoxide (IA) with the bimodal excitation properties of nitrogen-doped carbon dots (N-CDs). IA oxidizes the colorless 3,3',5,5'-tetramethylbenzidine into blue-colored 3,3',5,5'-tetramethylbenzidine oxide. Subsequently, nitrite further triggers a diazotization reaction, resulting in a color change from blue to green. Simultaneously, the fluorescence intensity of N-CDs at 470 nm decreases significantly, while the signal at 371 nm remains nearly unchanged, owing to the localized inner filter effect. Satisfactory results are attained with low limits of detection of 49 nM in the fluorometric mode and 73 nM in the colorimetric mode. Furthermore, an intelligent lateral flow assay platform is established for the visual detection of nitrite. Therefore, this work provides innovative guidance for nitrite detection in food safety.
由于亚硝酸盐与生物和环境过程相关，食品中亚硝酸盐的痕量检测日益受到关注。在此，通过将醇盐铁（IA）的类氧化酶活性与氮掺杂碳点（N-CDs）的双峰激发特性相结合，建立了一种用于亚硝酸盐检测的双模式荧光/比色传感器。IA将无色的3,3',5,5'-四甲基联苯胺氧化为蓝色的3,3',5,5'-四甲基联苯胺氧化物。随后，亚硝酸盐进一步引发重氮化反应，导致颜色从蓝色变为绿色。同时，由于局部内滤效应，N-CDs在470 nm处的荧光强度显著降低，而在371 nm处的信号几乎保持不变。荧光模式下检测限低至49 nM，比色模式下检测限低至73 nM，结果令人满意。此外，还建立了一个用于亚硝酸盐视觉检测的智能侧流分析平台。因此，这项工作为食品安全中亚硝酸盐的检测提供了创新指导。
