College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, People's Republic of China.
Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha, 410082, Hunan, China.
Mikrochim Acta. 2018 Dec 18;186(1):31. doi: 10.1007/s00604-018-3126-6.
A colorimetric assay is described for highly selective and sensitive determination of Hg(II) ions by using gold nanoparticles (AuNPs) functionalized with dithioerythritol (DETL). This method relies on the unique optical properties of DETL-functionalized AuNPs as well as the thiophilicity of both AuNPs and Hg(II). In the presence of DETL, the AuNPs aggregate due to ligand exchange between thiol groups of DETL and the citrate ions on the surface of AuNPs. This induces a color change from red to blue. On addition of Hg(II), the thiol groups preferably interact with Hg(II) rather than with AuNPs. Thus, the DETL is released from the surface of the AuNPs and binds to Hg(II). This triggers the redispersion of the AuNPs. The ratio of absorbances at 650 and 525 nm drops linearly in two Hg(II) concentration ranges (viz. from 0.1 to 0.5 μM, and from 0.5 to 5 μM). The ions Cu(II), Pb(II), and Cd(II) do not interfere even in the absence of masking agents. The detection limit is as low as 24 nM. Graphical abstract A highly selective colorimetric method based on gold nanoparticles via double ligand exchange reaction is described for determination of Hg. This assay can selective detect Hg with no response to major interfering metal ions such as Cu, Pb, and Cd in the absence of masking agents compared with previous works.
一种比色分析方法，用于通过使用二硫苏糖醇（DETL）功能化的金纳米粒子（AuNPs）高度选择性和灵敏地测定 Hg(II)离子。该方法依赖于 DETL 功能化的 AuNPs 的独特光学性质以及 AuNPs 和 Hg(II)的疏金性质。在 DETL 的存在下，由于 DETL 的巯基与 AuNPs 表面上的柠檬酸根离子之间的配体交换，AuNPs 聚集。这导致颜色从红色变为蓝色。加入 Hg(II)后，硫醇基团优先与 Hg(II)而不是 AuNPs 相互作用。因此，DETL 从 AuNPs 的表面释放出来并与 Hg(II)结合。这引发了 AuNPs 的再分散。在两个 Hg(II)浓度范围内（即从 0.1 到 0.5 μM 和从 0.5 到 5 μM），650 和 525 nm 处的吸光度之比呈线性下降。即使没有掩蔽剂，Cu(II)、Pb(II)和 Cd(II)离子也不会干扰。检测限低至 24 nM。摘要 描述了一种基于金纳米粒子的通过双重配体交换反应的高选择性比色法，用于测定 Hg。与以前的工作相比，该测定法在没有掩蔽剂的情况下，对主要干扰金属离子如 Cu、Pb 和 Cd 没有响应，能够选择性地检测 Hg。
