A convenient colorimetric method for sensitive and specific detection of cyanide using Ag@Au core–shell nanoparticles

• Published in: Sensors and actuators. B, Chemical Vol. 228; pp. 366 - 372
• Main Authors: Li, Yiran, Wang, Qianru, Zhou, Xiaomeng, Wen, Cong-ying, Yu, Jianfeng, Han, Xiguang, Li, Xiyou, Yan, Zi-feng, Zeng, Jingbin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 02.06.2016
• Subjects: Ag@Au core–shell nanoparticles; Colorimetric; Cyanide detection; PS 40; PS 40; Cyanide detection; Ag@Au core–shell nanoparticles; Colorimetric
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2016.01.022

Ag@Au core–shell nanoparticles are synthesized and used as probes for the colorimetric detection of cyanide withultra-high sensitivity and selectivity. [Display omitted] •Ag@Au core–shell NPs are synthesized and used as probes for cyanide sensing.•This assay is very convenient, highly sensitive and specific.•PS 40-Ag@Au core–shell NPs are stable in the presence of high salt.•The proposed method can be used for the analysis of cyanide in sewage water. In this work, we synthesize Ag@Au core–shell nanoparticles (NPs) and use them as probes for the colorimetric detection of cyanide in aqueous solution. Ag@Au core–shell NPs before and after cyanide treatment are characterized with UV–vis spectroscopy, transmission electron microscopy and electrospray ionization time-of-flight mass spectrometry. The sensing mechanism is based on the fact that cyanide can successively etch gold shells and silver cores of the bimetallic NPs, leading to color changes from purple to orange, yellow and finally colorless. The decreased absorbance intensity at 520nm is linear with the concentration of cyanide in the range of 0.4–32μM with a correlation coefficient of 0.995. The limit of detection is 0.16μM, which is, to our best knowledge, the lowest among the colorimetric methods. The colorimetric assay exhibits excellent selectivity for cyanide over the other 16 anions tested. The proposed method is used for the analysis of cyanide in drinking water, and the recoveries are in the range of 90.0–116.4% with the relative standard deviations lower than 6.7%. Furthermore, the Ag@Au core–shell NPs are functionalized with polysorbate 40 (PS 40), and the PS 40-Ag@Au core–shell NPs remain stable in the presence of high salt, which makes them feasible for the determination of cyanide in sewage samples with complex matrices.