Acta Chim. Sinica ›› 2019, Vol. 77 ›› Issue (4): 379-386.

Article

### 基于功能化Fe3O4@Ag纳米粒子快速检测Hg2+的SERS方法

1. a 中国科学院合肥智能机械研究所 合肥 230031;
b 中国科学技术大学 合肥 230026;
c 中国科学院传感技术国家重点实验室 合肥 230031
• 投稿日期:2018-11-26 发布日期:2019-02-15
• 通讯作者: 赵爱武 E-mail:awzhao@iim.ac.cn
• 基金资助:

项目受国家自然基金委面上项目（No.61875255）和合肥物质科学技术中心方向项目（No.2018ZYFX005）资助.

### A SERS Approach for Rapid Detection of Hg2+ Based on Functionalized Fe3O4@Ag Nanoparticles

Zuo Fangtaoa,b,c, Xu Weia,b,c, Zhao Aiwua,b,c

1. a Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031;
b University of Science and Technology of China, Hefei, 230026 Anhui;
c State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Hefei 230031
• Received:2018-11-26 Published:2019-02-15
• Contact: 10.6023/A18110475 E-mail:awzhao@iim.ac.cn
• Supported by:

Project supported by the National Natural Science Foundation of China (No. 61875255) and the Direction Program of Hefei Center of Physical Science and Technology (No. 2018ZYFX005).

Mercury is an important pollutant, which has attracted wide attention in recent years. Up to now, based on surface enhanced raman spectroscopy (SERS) strategy for detection of Hg2+ is very attractive due to its high sensitivity among various detection methods. Based on the "turn-off" mechanism, we synthesized a magnetic Fe3O4@Ag nanomaterial for SERS detection of Hg2+. The magnetic-plasma resonance nanoparticles, which combine magnetic and plasma resonance properties, can be used for SERS detection of mercury ions with high sensitivity and selectivity. Firstly, the magnetic nanoparticles were prepared by solvothermal reaction, and silver nanoparticles were coated on the surface of magnetic nanoparticles after modification of amino groups. By modifying the positively charged PDADMAC, polyDADMAC (PDDA) layer, the negatively charged methyl orange probe molecule is adsorbed on the surface of Fe3O4@Ag, and in the presence of Hg2+, a significant decrease in SERS signal can be observed. Due to the short-time reaction of Hg2+ and Ag nanoparticles, an amalgam is formed on the surface of the Ag particles, which affects the surface plasmon resonance (SPR) characteristics of the Ag nanoparticles, resulting in enhanced attenuation of the electromagnetic field. And the short-time reaction of Hg2+ and Ag nanoparticles also leads to a decrease in the surface zeta potential of the Ag nanoparticles and affects the adsorption of the Raman probe molecules on the surface, resulting in a decrease in the SERS signal. Therefore, the decrease of SERS intensity in the presence of Hg2+ is mainly attributed to the interaction between Hg2+ and Ag nanoparticles. Through our experiments, it can be proved that the detection limit of the method based on "turn-off" mechanism for detecting Hg2+ ions can be as low as 10-10 mol/L. In addition, this method also shows high selectivity for divalent mercury ions. The SERS nanosensor designed in this experiment can be used to detect the specificity and ultra-sensitivity of Hg2+ in the environment, and it also provides great potential for the construction of SERS nanosensor for heavy metal ions.