Li Junrong, Zhang Guannan, Wang Lihua, Shen Aiguo, Hu Jiming
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Talanta. 2015 Aug 1;140:204-211. doi: 10.1016/j.talanta.2015.03.050. Epub 2015 Apr 1.
In this work, we suggest a chitosan-modified popcorn-like Au-Ag nanoparticles (CSPNPs) based assay for high sensitive detection of melamine, in which CSPNPs not only provide with an intrinsic peroxidase-like activity but also act as surface enhanced Raman scattering (SERS) substrates. CSPNPs can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to the charge transfer complex (CTC), which contributes to a tremendous surface-enhanced resonant Raman scattering (SERRS) signals with 632.8 nm laser excitation. The target molecule melamine can generate an additional compound with H2O2, which means the available amount of H2O2 for the oxidation of TMB reduced. Correspondingly, the SERRS intensity of CTC is decreased. The decreased Raman intensity is proportional to the concentration of melamine over a wide range from 10 nM to 50 μM (R(2)=0.989), with a limit of detection (LOD) of 8.51 nM. Moreover, the proposed highly selective method is fully capable of rapid, separation-free detection of melamine in milk powder.
在本研究中，我们提出了一种基于壳聚糖修饰的爆米花状金-银纳米颗粒（CSPNPs）的三聚氰胺高灵敏检测方法，其中CSPNPs不仅具有内在的类过氧化物酶活性，还可作为表面增强拉曼散射（SERS）基底。CSPNPs能够催化H2O2将3,3',5,5'-四甲基联苯胺（TMB）氧化为电荷转移复合物（CTC），在632.8 nm激光激发下产生强烈的表面增强共振拉曼散射（SERRS）信号。目标分子三聚氰胺能与H2O2生成一种额外的化合物，这意味着用于氧化TMB的H2O2可用量减少。相应地，CTC的SERRS强度降低。拉曼强度的降低与三聚氰胺浓度在10 nM至50 μM的宽范围内成正比（R(2)=0.989），检测限（LOD）为8.51 nM。此外，所提出的高选择性方法完全能够对奶粉中的三聚氰胺进行快速、无需分离的检测。
