论文期刊

A colorimetric/SERS dual-mode sensing method for the detection of mercury(II) based on rhodanine-stabilized gold nanobipyramids




作者: Ying Qi, Jing Zhao, Guo-jun Weng, Jian-jun Li, Xin Li, Jian Zhu * , Jun-wu Zhao*
发表/完成日期: 2018-11-01
期刊名称: Journal of Materials Chemistry C
期卷:
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论文简介
This study demonstrates a novel strategy for colorimetric and surface enhanced Raman scattering (SERS)
dual-mode sensing of mercury (Hg2+) based on rhodanine-stabilized gold nanobipyramids (Au NBs). The
Au NBs are first modified by rhodanine through gold–thiol (Au–S) affinity interactions. Next, the addition
of Hg2+ into the rhodanine-stabilized Au NBs induces the formation of a partition layer with tunable
thickness on the surface of the Au NBs, resulting in the redshift of the longitudinal localized surface
plasmonic resonance (LSPR) wavelength of the Au NBs, which further leads to the colloidal color
changing from blue grey to red. The sensing based on the partition layer-induced absorption spectrum
redshift of the longitudinal LSPR has a linear response for the concentration of Hg2+ from 5.0  107 to
6.0  105 M with a limit of detection (LOD) of 2.0  107 M measured by an absorption spectrometer.
The LOD for Hg2+ is 2.0  106 M by the naked eye. Meanwhile, the partition layer on the surface of the
Au NBs draws the Raman reporter molecule (4-mercaptobenzoic acid (4-MBA)) away from the surface
of the Au NBs and decreases the LSPR phenomenon of the Au NBs, which leads to the SERS intensity of
4-MBA decreasing with the addition of Hg2+. The sensing based on the partition layer-induced SERS
intensity decrease of 4-MBA has a linear response for the logarithm of Hg2+ concentration from
1.0  1010 to 1.0  105 M with a LOD of 5.0  1011 M. Therefore, the rhodanine-stabilized Au NBs can
be used not only as a naked-eye sensor of Hg2+, but also as a highly selective SERS probe. Furthermore,
other cations do not interfere with this dual-mode sensor, and the applicability of the sensor is well
demonstrated in real samples with satisfactory results. Compared with the methods in the literature, which
generally exploit the aggregation or etching of nanoparticles, this method depends on the formation of a
partition layer on the surface of the nanoparticles and provides a new strategy for optical sensing that relies
on the change in dielectric environment near the surface of the nanoparticles.