Department of Food Engineering, Faculty of Engineering, Hacettepe University, 06800 Beytepe, Ankara, Turkey.
Anal Bioanal Chem. 2012 Jun;403(7):2009-17. doi: 10.1007/s00216-012-5971-1. Epub 2012 May 4.
A new method based on surface-enhanced Raman spectroscopy (SERS) has been developed for sensitive and rapid detection of melamine. Spherical magnetic-core gold-shell nanoparticles (AuNPs) and rod-shaped gold nanoparticles (nanorods) labeled with a Raman-active compound were used to form a complex with the melamine molecules. 5,5'-Dithiobis(2-nitrobenzoic acid) was used as Raman-active compound because it is readily adsorbed by a gold nanoparticle surface forming a self-assembled monolayer (SAM) and has strong Raman scattering at 1330 cm(-1), because of the symmetric NO(2) stretch. The calibration curve was obtained by plotting Raman band area at 1330 cm(-1) against melamine concentration. A linear relationship was obtained with a high determination coefficient (R(2)=0.997). The method was validated for linearity, sensitivity, precision (intra-day and inter-day repeatability), and recovery. In the model system, the limits of detection (LOD) and quantification (LOQ) were 0.38 and 1.27 mg L(-1), respectively. For melamine-spiked milk samples, LOD and LOQ values were 0.39 mg L(-1) and 1.30 mg L(-1), respectively. Intra and inter-day precision were 3.73 and 4.94 %, respectively. This method was applied to samples of skimmed milk that had been spiked with melamine at different concentrations. The recovery of the method was 95-109 % in the concentration range 2-15 mg L(-1), and average RSD was 1.71 %. Total analysis time was less than 15 min.
一种基于表面增强拉曼光谱（SERS）的新方法已被开发用于灵敏和快速检测三聚氰胺。使用标记有拉曼活性化合物的球形磁核金壳纳米粒子（AuNPs）和棒状金纳米粒子（纳米棒）与三聚氰胺分子形成复合物。5,5'-二硫代双（2-硝基苯甲酸）被用作拉曼活性化合物，因为它很容易被金纳米粒子表面吸附形成自组装单层（SAM），并且在 1330 cm(-1)处具有很强的拉曼散射，因为对称的 NO(2)拉伸。通过绘制 1330 cm(-1)处的拉曼带面积与三聚氰胺浓度的关系得到校准曲线。得到了一个具有高决定系数（R(2)=0.997）的线性关系。该方法经过线性度、灵敏度、精密度（日内和日间重复性）和回收率的验证。在模型系统中，检测限（LOD）和定量限（LOQ）分别为 0.38 和 1.27 mg L(-1)。对于三聚氰胺掺杂的牛奶样品，LOD 和 LOQ 值分别为 0.39 mg L(-1)和 1.30 mg L(-1)。日内和日间精密度分别为 3.73%和 4.94%。该方法应用于不同浓度三聚氰胺掺杂的脱脂牛奶样品。该方法在 2-15 mg L(-1)浓度范围内的回收率为 95-109%，平均 RSD 为 1.71%。总分析时间小于 15 分钟。
