表面增强拉曼散射效应无标记、无分离检测三聚氰胺

A Label-free and Separation-free Detection for Melamine Based on Surface Enhanced Raman Scattering

利用纳米金的表面增强拉曼效应,建立了一种快速、灵敏、无标记、无分离的检测三聚氰胺的分析方法。通过柠檬酸钠还原法制得平均粒径为30 nm的纳米金溶胶,利用Au-S之间的共价键作用,将对巯基苯硼酸（4-MPBA）自组装到纳米金的表面,构建了一个三聚氰胺的检测平台。当溶液中存在三聚氰胺（ MA）时, MA与4-MPBA之间存在强烈的氢键作用,使4-MPBA功能化的纳米金发生聚集。而且,MA的浓度越高,纳米金的聚集程度越大,形成的“热点”越多,4-MPBA和MA的拉曼信号越强。4-MPBA与MA的拉曼特征峰分别位于1076和715 cm-1处,若以I715与I1076的比值为依据,便可以实现三聚氰胺的定性及定量的检测,线性检测范围为0.1~1.5μmol/L,检出限（LOD）为0.02μmol/L。

A rapid, sensitive, label-free and separation-free analytical method for determination of melamine （ MA） was developed based on surface enhanced Raman scattering （ SERS ） effect of gold nanoparticles. Through tri-sodium citrate reduction method, gold nanoparticles with average diameter of 30 nm were obtained. The melamine detection platform was constructed after self-assembling 4-mercapto phenylboronic acid （4-MPBA） on the surface of gold nanoparticles through Au S covalent bond. When MA existed in solution, 4-MPBA functionalized gold nanoparticles would aggregate because of strong hydrogen bond interaction between MA and 4-MPBA. Moreover, following increase of the concentration of MA, gold nanoparticles would aggregate more intensively and form more ＂hot spots＂. As a result, Raman signal of 4-MPBA and MA was enhanced greatly. The characteristic Raman peaks of 4-MPBA and MA respectively located at 1076 cm-1 and 715 cm-1 . Hence, the qualitative and quantitative detection for MA were realized based on the ratio value of I715 cm-1 to I1076 cm-1 . The linear range of MA detection was 0 . 1 μmol/L-1. 5 μmol/L. The limit of detection （LOD） reached 0. 02 μmol/L in terms of three times signal to noise.