Key Laboratory of Coastal Zone Environmental Processes, CAS, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.
Anal Bioanal Chem. 2011 Jul;401(1):333-8. doi: 10.1007/s00216-011-5067-3. Epub 2011 May 15.
A surface-enhanced Raman scattering (SERS) strategy based on 4-mercaptopyridine (MPY)-modified gold nanoparticles (AuNPs) was developed for the rapid and sensitive detection of melamine in milk powder. The SERS measurement of melamine strongly relied on the "hotspot" effect, in which AuNPs immediately aggregated upon the addition of melamine, leading to significantly enhanced Raman intensity of the reporter molecule MPY and a color change for the solution from red to blue-gray. The limit of detection based on a signal to noise of 3 (S/N = 3) was found to be as low as 0.1 ppb of melamine, with an excellent linearity of 0.5-100 ppb, demonstrating a higher sensitivity and a wider quantitation range than direct SERS sensing methods based on enhanced substrate. An impressive specificity for melamine detection over various common metal ions and excipients in dairy products, even at concentrations of 100-fold higher than melamine, was achieved. Good recoveries of 88.5% and 111.7% were obtained from milk samples spiked to 20 and 100 ppb levels, respectively. The proposed method is potentially applicable for the rapid in situ determination of melamine in complex matrices.
基于 4-巯基吡啶（MPY）修饰的金纳米粒子（AuNPs）的表面增强拉曼散射（SERS）策略被开发用于快速灵敏地检测奶粉中的三聚氰胺。三聚氰胺的 SERS 测量强烈依赖于“热点”效应，即在添加三聚氰胺后，AuNPs 立即聚集，导致报告分子 MPY 的拉曼强度显著增强，溶液颜色从红色变为蓝灰色。基于信噪比为 3（S/N = 3）的检测限低至 0.1 ppb 的三聚氰胺，具有 0.5-100 ppb 的优异线性度，与基于增强衬底的直接 SERS 传感方法相比，具有更高的灵敏度和更宽的定量范围。即使在浓度比三聚氰胺高 100 倍的情况下，该方法也能对乳制品中的各种常见金属离子和赋形剂进行三聚氰胺检测，表现出令人印象深刻的特异性。在添加到 20 和 100 ppb 水平的牛奶样品中，回收率分别为 88.5%和 111.7%。该方法有望用于复杂基质中三聚氰胺的快速现场测定。
