化学学报 ›› 2015, Vol. 73 ›› Issue (5): 409-415.DOI: 10.6023/A15010039 上一篇    下一篇

研究论文

基于荧光树状聚合物的高灵敏化学反应型汞离子传感器

张崇洋, 孟玉珠, 匡金志, 徐岚   

  1. 西南大学化学化工学院 重庆 400715
  • 收稿日期:2015-01-15 出版日期:2015-05-14 发布日期:2015-03-17
  • 通讯作者: 徐岚 E-mail:xulan@swu.edu.cn
  • 基金资助:

    项目受国家自然科学基金(No. 51103120)资助.

Highly Sensitive Detection of Hg2+ by a Reaction-Based Dendritic Fluorescent Polymer Chemosensor

Zhang Chongyang, Meng Yuzhu, Kuang Jinzhi, Xu Lan   

  1. School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
  • Received:2015-01-15 Online:2015-05-14 Published:2015-03-17
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 51103120).

以2,4-二氯苯硫酚为单体, 通过“一步法”合成了平均分子量为10.910 kD的荧光树状超支化聚苯硫醚(HPPS). 通过亲核取代和水解反应对HPPS进行了外围氨基修饰, 通过偶氮共价键使HPPS与氨基硫脲小分子相连, 制备出了高灵敏度树状聚合物基多位点反应型汞离子传感器. 基于汞离子与氨基硫脲脱硫关环反应和超支化聚苯硫醚对光信号的放大传递作用, 传感器对汞离子有灵敏的荧光响应信号, 线性范围为2.5~100 nmol/L, 检出限为0.46 nmol/L. 并利用分子模拟计算对反应识别机理进行了讨论.

关键词: 树状聚合物, 超支化聚苯硫醚, 汞离子, 荧光, 高灵敏传感器

In this work, spherical polymer-based fluorescent sensor with high sensitivity for Hg2+ was first designed and synthesized. Dendritic hyperbranched poly(phenylene sulfide) (HPPS) with an average molecular weight of 10.910 kD and spherical conformation was synthesized via one-pot reaction procedure with 2,4-dichlorothiophenol as monomer. Because of aryl groups conjugated with sulfur atoms and dendritic topology, HPPS displayed remarkable chemical stability, fluorescent and multiple reaction sites. It inspires us to employ it as a smart matrix to develop polymer fluorescent sensor. Through the nucleophilic substitution and hydrolysis reaction, peripheral Cl atoms of HPPS were modified by NH2 groups, and the resulted HPPS-NH2 was achieved. The fluorescent sensor (HPPSNT) was fabricated by HPPS-NH2 azo N=N covalently bonded to small probe molecule Benzamide, N-[[[2-(phenylamino)ethyl]amino]thioxomethyl], which can react with Hg2+sensitively and selectively, causing desulfurization and cyclization. The results showed that HPPSNT sensor exhibited excellent sensitivity towards Hg2+, and can selectively recognize Hg2+ over other metal ions, such as Al3+, Ba2+, Cd2+, Cu2+, Fe3+, Zn2+, Pb2+, Mg2+, K+, Ag+. It was found that the decreased absorption of fluorescent signal intensity was proportional to the mercury content concentration in a range of 2.5~100 nmol/L with a coefficient of correlation R of 0.9931, and a detection limit of 0.46 nmol/L. The mechanism of high sensitivity was discussed. HPPS was rich in sulfur atoms inside, which has a strong affinity for Hg2+, Cu2+, Fe3+, Ag+, consequently, fluorescence of HPPS-NH2 was quenched dramatically in the presence of these ions. As the peripheral small probe molecules preferentially reacted with Hg2+ via desulfurization and cyclization reaction, it is by such reactions instead of by quenching to cause fluorescence intensity of HPPSNT weakened. The decline of fluorescence intensity via desulfurization and cyclization reaction can be explained through the simulation calculation of bond length by Gaussian 09.

Key words: dendritic polymer, hyperbranched poly(phenylene sulfide), mercury ions, fluorescene, highly sensitive sensor