聚甲基丙烯酸单层保护金纳米粒子选择性检测Pb2+

以聚甲基丙烯酸单层保护的金纳米粒子(GNPs)作为传感器, 实现了水溶液中Pb²⁺的选择性循环检测.先采用柠檬酸钠还原法获得尺寸均匀的GNPs, 再通过具有硫醇端基的聚甲基丙烯酸与金的强耦合作用, 获得了聚甲基丙烯酸单层保护的金纳米粒子(PMAA-@-GNPs).动态光散射、紫外-可见吸收光谱及透射电子显微镜表征证实了其单层结构.在Pb²⁺的诱导下, PMAA-@-GNPs溶液颜色从酒红色变为紫色并可肉眼识别.透射电子显微镜结果证实, 这种变化是由于Pb²⁺交联羧基使聚合物发生收缩, 并诱导GNPs的聚集所致.对比Pb²⁺与Hg²⁺, Mg²⁺, Cu²⁺, Zn²⁺, Na⁺, Ni²⁺, Fe³⁺, Cd²⁺, K⁺和Fe²⁺溶液颜色的变化, 证实此体系具有一定的选择性.用EDTA可夺取交联的Pb²⁺, 使PMAA-@-GNPs 的吸收峰恢复并可用于循环检测Pb²⁺.

Selective Detection of Pb2+ Using Poly(methylacrylic acid) Monolayer-protected Gold Nanoparticles

In this work, the selective colorimetric detection of Pb²⁺ was studied using poly(methylacrylic acid) monolayer-protected gold nanoparticles(PMAA-@-GNPs). The GNPs with uniform size and distribution were firstly synthesized by the citrate reduction method. Then PMAA-@-GNPs were prepared by the strong binding of the GNPs and the thiol ends groups of the PMAA. The monolayer structure was proved by the dynamic light scattering, UV-visible spectra and transmission electron microscopy. In the presence of Pb²⁺, the color of the solution changed from wine red to purple and could be measured by visual inspection. TEM results demonstrated that the induced aggregation of GNPs by Pb²⁺ crosslinking carboxyl groups. The selectivity of Pb²⁺ detection has also been investigated by comparing the color changes of solutions with other metal ions, including Hg²⁺, Mg²⁺, Cu²⁺, Zn²⁺, Na⁺, Ni²⁺, Fe³⁺, Cd²⁺, K⁺ and Fe²⁺. After treated by EDTA, the aggregated PMMA-@-GNPs could be renewable and recycled detecting Pb²⁺.