Colorimetric and SERS dual-mode sensing of mercury (II) based on controllable etching of Au@Ag core/shell nanoparticles

• Published in: Sensors and actuators. B, Chemical Vol. 330; p. 129364
• Main Authors: Wang, Jinhua, Wu, Jiamin, Zhang, Yuping, Zhou, Xia, Hu, Ziwei, Liao, Xiaojian, Sheng, Bingbing, Yuan, Kaisong, Wu, Xueqiang, Cai, Huaihong, Zhou, Haibo, Sun, Pinghua
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-03-2021; Elsevier Science Ltd
• Subjects: Colorimetry; Core-shell nanoparticles; Core-shell particles; Damage accumulation; Dual-mode; Etching; Gold; Heavy metals; Mercury (metal); Mercury ions; Nanoparticles; Raman spectroscopy; Selectivity; SERS; Silver; Traditional Chinese medicine; Water sampling; Dual-mode; Core-shell nanoparticles; Colorimetry; Mercury ions; SERS
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2020.129364

A colorimetric and SERS dual-mode method based on the controllable etching of Au@Ag core/shell nanoparticles was proposed for the selective and sensitive detection of Hg2+.
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•Colorimetric and SERS dual-mode sensing of mercury (II) was established.•Au@Ag core/shell nanoparticles were used as the dual-mode detection probe without modification.•The mechanism was based on the suppression of S2O32− etching Au@Ag NPs.•As low as 0.1 nM of Hg2+ could be quantified by UV–vis and Raman spectroscopy.•The dual-mode detection strategy provides a good route for on-site rapid and accurate detection of trace Hg2+.
Mercury ion (Hg2+) is a bio-accumulative and toxic heavy metal, which has caused significant damage to our health. It is vital to establish a method for the determination of Hg2+. Here, a new strategy for colorimetric/SERS dual-mode determination of Hg2+ was proposed based on controllable etching Au@Ag NPs. The silver shells could be etched by S2O32− causing the orange colloidal solution to turn into brick red. However, after Hg2+ is added, the etching effect is suppressed due to the reaction between Hg2+ and S2O32− to form an insoluble substance HgS. As a result, the UV–vis absorption at 394 nm and Raman intensity of R6 G increase with a silver shell-less etched by S2O32−. About the colorimetric method, the limit of detection was 2 μM and 0.2 μM through the naked eye and UV–vis spectroscopy, respectively. Moreover, the SERS method possesses a linear regression for the concentration of Hg2+ (0.1 nM-1 μM), and the LOD was 0.1 nM. Furthermore, the sensing strategy has been used to determine Hg2+ in traditional Chinese medicine and real water samples. The selectivity and practicability studies indicate that our method has excellent specificity and sensitivity. Thus, this strategy is suitable for on-site fast detecting of Hg2+.