聚甲基丙烯酸单层保护金纳米粒子选择性检测Pb^(2+)

Selective Detection of Pb^(2+) Using Poly( methylacrylic acid) Monolayer-protected Gold Nanoparticles

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+.

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 dy namic 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 tre＋3＋l y EDTA, the aggrega- ted PMMA-@-GNPs could be renewable and recycled detecting Pb2＋.