Ke Jun, Li Xinyong, Zhao Qidong, Hou Yang, Chen Junhong
State Key Laboratory of Fine Chemicals, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
Sci Rep. 2014 Jul 9;4:5624. doi: 10.1038/srep05624.
Mercury is one of the most acutely toxic substances at trace level to human health and living thing. Developing a rapid, cheap and water soluble metal sensor for detecting mercury ions at ppb level remains a challenge. Herein, a metal sensor consisting of MPA coated Mn doped ZnSe/ZnS colloidal nanoparticles was utilized to ultrasensitively and selectively detect Hg(2+) ions with a low detection limit (0.1 nM) over a dynamic range from 0 to 20 nM. According to strong interaction between thiol(s) and mercury ions, mercaptopropionic acid (MPA) was used as a highly unique acceptor for mercury ions in the as-obtained ultrasensitive sensor. In the presence of mercury ions, colloidal nanoparticles rapidly agglomerated due to changes of surface chemical properties, which results in severe quenching of fluorescent intensity. Meanwhile, we find that the original ligands are separated from the surface of colloidal nanoparticles involving strongly chelation between mercury ion and thiol(s) proved by controlled IR analysis. The result shows that the QD-based metal ions sensor possesses satisfactory precision, high sensitivity and selectivity, and could be applied for the quantification analysis of real samples.
汞是痕量水平下对人类健康和生物毒性最强的物质之一。开发一种快速、廉价且水溶性的金属传感器来检测十亿分之一水平的汞离子仍然是一项挑战。在此，利用一种由巯基丙酸（MPA）包覆的锰掺杂硒化锌/硫化锌胶体纳米粒子组成的金属传感器，在0至20 nM的动态范围内以低检测限（0.1 nM）超灵敏且选择性地检测Hg(2+)离子。根据硫醇与汞离子之间的强相互作用，巯基丙酸（MPA）被用作所制备的超灵敏传感器中汞离子的高度独特受体。在汞离子存在的情况下，由于表面化学性质的变化，胶体纳米粒子迅速聚集，导致荧光强度严重猝灭。同时，我们发现通过可控红外分析证明，由于汞离子与硫醇之间的强螯合作用，原始配体从胶体纳米粒子表面分离。结果表明，基于量子点的金属离子传感器具有令人满意的精密度、高灵敏度和选择性，可用于实际样品的定量分析。
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