Yu Yuebin, Chen Guoqing, Ma Chaoqun, Li Lei, Yang Taiqun, Zhu Chun, Gao Hui, Hu Anqi, Qian Yali, Guo Xingyi, Yang Wenhui, Yang Tingjian, Liu Wang
School of Science, Jiangnan University, Wuxi 214122, China.
Jiangsu Provincial Research Center of Light Industrial Optoelectronic Engineering and Technology, Wuxi 214122, China.
Anal Methods. 2025 Jul 24;17(29):6133-6141. doi: 10.1039/d5ay00765h.
Melamine (MEL) is frequently adulterated in dairy products to manipulate protein content test results due to its high nitrogen content. In this study, a fluorescent probe based on ofloxacin (OFL) and gold nanoparticles (AuNPs) was proposed for the specific and sensitive detection of MEL. In the pH range of 4.5-7.5, the fluorescence spectrum of OFL exhibits a high degree of overlap with the absorption spectrum of AuNPs, and interactions based on fluorescence resonance energy transfer (FRET) occur, with significant quenching of OFL fluorescence accompanied by a change in fluorescence lifetime. After being incorporated into MEL, the amino group of MEL specifically interacted with the surface of AuNPs through coordination. This interaction triggered the aggregation of AuNPs, which in turn led to the fluorescence recovery of OFL. The detection of melamine was accomplished by quantifying the change in fluorescence intensity of OFL. Under optimized conditions, the MEL concentration exhibited a strong linear relationship with the relative fluorescence intensity of the probe ( = 0.994) within a range of 0.1 to 1.6 μM. The limit of detection was determined to be 7.28 nM. It is noteworthy that the method was validated in real milk samples, with recovery rates ranging from 98.2% to 107.1%. The method exhibits excellent selectivity and sensitivity for MEL, making it a suitable tool for the environmental detection of milk.
三聚氰胺（MEL）常被掺入乳制品中以操纵蛋白质含量检测结果，因为其含氮量高。在本研究中，提出了一种基于氧氟沙星（OFL）和金纳米颗粒（AuNPs）的荧光探针，用于特异性和灵敏地检测MEL。在4.5 - 7.5的pH范围内，OFL的荧光光谱与AuNPs的吸收光谱呈现高度重叠，并发生基于荧光共振能量转移（FRET）的相互作用，伴随着荧光寿命的变化，OFL荧光显著猝灭。掺入MEL后，MEL的氨基通过配位与AuNPs表面特异性相互作用。这种相互作用引发了AuNPs的聚集，进而导致OFL的荧光恢复。通过定量OFL荧光强度的变化来完成三聚氰胺的检测。在优化条件下，在0.1至1.6 μM范围内，MEL浓度与探针的相对荧光强度呈现强线性关系（ = 0.994）。检测限确定为7.28 nM。值得注意的是，该方法在实际牛奶样品中得到验证，回收率在98.2%至107.1%之间。该方法对MEL表现出优异的选择性和灵敏度，使其成为牛奶环境检测的合适工具。
