Yuan Huizhen, Sun Guangyi, Peng Wei, Ji Wei, Chu Shuwen, Liu Qiang, Liang Yuzhang
School of Physics, Dalian University of Technology, Dalian 116024, China.
School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
Nanomaterials (Basel). 2021 Feb 4;11(2):397. doi: 10.3390/nano11020397.
Mercury ion (Hg) is considered to be one of the most toxic heavy metal ions. Once the content of Hg exceeds the quality standard in drinking water, the living environment and health of human beings will be threatened and destroyed. Therefore, the establishment of simple and efficient methods for Hg ion detection has important practical significance. In this paper, we present a highly sensitive and selective fiber-optic surface plasmon resonance (SPR) Hg ion chemical nanosensor by designing thymine (T)-modified gold nanoparticles (Au NPs/T) as the signal amplification tags. Thymine-1-acetic acid (T-COOH) was covalently coupled to the surface of 2-aminoethanethiol (AET)-modified Au NPs and Au film by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-Hydroxysuccinimide (EDC/NHS) activation effect, respectively. In the presence of Hg ions, the immobilized thymine combines specifically with Hg ions, and forms an Au/thymine-Hg-thymine/Au (Au/T-Hg-T/Au) complex structure, leading to a shift in SPR wavelength due to the strong electromagnetic couple between Au NPs and Au film. Under optimal conditions, the proposed sensor was found to be highly sensitive to Hg in the range of 80 nM-20 µM and the limit of detection (LOD) for Hg was as low as 9.98 nM. This fiber-optic SPR sensor afforded excellent selectivity for Hg ions against other heavy metal ions such as Fe, Cu, Ni, Ba, K, Na, Pb, Co, and Zn. In addition, the proposed sensor was successfully applied to Hg assay in real environmental samples with excellent recovery. Accordingly, considering its simple advantages, this novel strategy provides a potential platform for on-site determination of Hg ions by SPR sensor.
汞离子（Hg）被认为是毒性最强的重金属离子之一。一旦Hg含量超过饮用水质量标准，人类的生存环境和健康将受到威胁和破坏。因此，建立简单高效的Hg离子检测方法具有重要的现实意义。本文通过设计胸腺嘧啶（T）修饰的金纳米粒子（Au NPs/T）作为信号放大标签，提出了一种高灵敏度和选择性的光纤表面等离子体共振（SPR）Hg离子化学纳米传感器。胸腺嘧啶-1-乙酸（T-COOH）分别通过1-乙基-3-（3-二甲基氨基丙基）碳二亚胺盐酸盐/N-羟基琥珀酰亚胺（EDC/NHS）活化作用，共价偶联到2-氨基乙硫醇（AET）修饰的Au NPs和Au膜表面。在Hg离子存在下，固定化的胸腺嘧啶与Hg离子特异性结合，形成Au/胸腺嘧啶-Hg-胸腺嘧啶/Au（Au/T-Hg-T/Au）复合结构，由于Au NPs与Au膜之间的强电磁耦合导致SPR波长发生偏移。在最佳条件下，所提出的传感器在80 nM至20 μM范围内对Hg具有高灵敏度，Hg的检测限低至9.98 nM。这种光纤SPR传感器对Hg离子具有出色的选择性，可抵抗其他重金属离子，如Fe、Cu、Ni、Ba、K、Na、Pb、Co和Zn。此外所提出的传感器成功应用于实际环境样品中的Hg测定，回收率良好。因此，考虑到其简单的优点，这种新策略为通过SPR传感器现场测定Hg离子提供了一个潜在平台。
