Department of Physics, Shanghai Normal University, Shanghai 200234, PR China.
Department of Physics, Shanghai Normal University, Shanghai 200234, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 Dec 5;223:117269. doi: 10.1016/j.saa.2019.117269. Epub 2019 Jun 11.
A direct and sensitive method to detect melamine in infant formula milk powder solution based on the SERS effect of silver film over nanospheres (AgFON) was developed. AgFON was prepared by vacuum magnetron sputtering and dip-coating methods. The surface morphology and roughness were characterized by using scanning electron microscope and atomic force microscope. AgFON was used as a substrate to detect the SERS spectra of melamine in infant formula milk powder solution directly without any pretreatments. Semi-quantitative analyses of melamine with various concentrations in milk powder solution were carried out. A good linearity with correlation coefficient of 0.9926 between peak intensity and concentration was obtained from 2 to 25 mg/L. Furthermore, the as-prepared AgFON substrate had good uniformity with relative standard deviation value of 5.56% collected from ten randomly selected positions. The electric field distribution of AgFON was simulated by finite difference time domain solution, which revealed that the huge enhancement of Raman signals was ascribed to the high-density hot spots of the substrate.
基于银膜覆盖纳米球（AgFON）的 SERS 效应，建立了一种直接、灵敏的检测婴幼儿配方奶粉中三聚氰胺的方法。AgFON 通过真空磁控溅射和浸涂法制备。采用扫描电子显微镜和原子力显微镜对其表面形貌和粗糙度进行了表征。AgFON 无需任何预处理即可直接用作基底，用于检测婴幼儿配方奶粉溶液中的 SERS 光谱。对奶粉溶液中不同浓度的三聚氰胺进行了半定量分析。在 2 至 25 mg/L 范围内，从峰强度和浓度之间获得了良好的线性关系，相关系数为 0.9926。此外，所制备的 AgFON 基底具有良好的均匀性，从十个随机选择的位置采集到的相对标准偏差值为 5.56%。通过时域有限差分法模拟了 AgFON 的电场分布，表明拉曼信号的巨大增强归因于基底的高密度热点。
