Acta Chimica Sinica ›› 2012, Vol. 70 ›› Issue (18): 1945-1949.DOI: 10.6023/A12060319 Previous Articles     Next Articles



罗金尚, 王莹莹, 谭克俊   

  1. 发光与实时分析教育部重点实验室 西南大学化学化工学院 重庆 400715
  • 投稿日期:2012-06-18 发布日期:2012-07-24
  • 通讯作者: 谭克俊
  • 基金资助:

    项目受国家自然科学基金(No. 20877063)和重庆市科委重点实验室专项经费资助.

Colorimetric Detection of Mercury(Ⅱ) Based on Silver Nanoparticles

Luo Jinshang, Wang Yingying, Tan Kejun   

  1. Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715
  • Received:2012-06-18 Published:2012-07-24
  • Supported by:

    Supporting information for this article is available free of charge via the Internet at Project supported by the National Natural Science Foundation of China (No. 20877063) and the Special Fund of Chongqing Key Laboratory (CSTC).

In this work, the colorimetric detection assay of mercury has been proposed based on silver nanoparticles (AgNPs) aggregation. In basic medium with 1.75 mmol/L NaOH, the stable and monodisperse silver nanoparticles, which coated by polydopamine, was prepared by a one-pot reduction process using dopamine as a reducing agent. The polydopamine adsorption with Hg2+ can induce the aggregation of silver nanoparticles resulting in the decrease of absorption signal of AgNPs at 405 nm and the color change of the solutions. It was found that the decreased absorption signal intensity was proportional to the mercury content in a range of 0.5~5.0 μmol/L. According to this, the ultraviolet-visible absorption spectrum method and colorimetric method for determination of Hg2+ was developed. The limit of detection is 50 nmol/L. In this work, UV-vis absorption spectrum, scanning electron microscope (SEM) and infrared (IR) spectrum were investigated. The mechanism of this reaction was discussed. The IR spectrum of special functional groups approved that polydopamine was formed on the surface of AgNPs. The UV-Vis absorption peak at 405 nm and SEM photos indicated that the stable and monodisperse AgNPs was prepared and the aggregation of AgNPs was occurred after the addition of Hg2+. The tolerance of coexisting foreign substances in system was also studied and the experimental results indicated that the interferences of other common metal ions were small. The experimental condition optimization results show that when the NaOH concentration is 1.75 mmol/L and dopamine concentration is 40 μmol/L, the system has a good response for Hg2+. The proposed method was successfully used to detection of Hg2+ in tap water with a recovery range of 93.0% to 105.5% and RSD≤4.4%. This method show some advantages including low-cost, rapidity, simplicity and selectivity. Moreover, it can achieve a visual sensing of Hg2+.

Key words: dopamine, nanoparticles, mercury, colorimetric method, UV/Vis spectroscopy