Colorimetric detection of Cr 6+ ions based on surface plasma resonance using the catalytic etching of gold nano-double cone @ silver nanorods

• Published in: Analytica chimica acta 2021-03, Vol.1149, p.238141
• Main Authors: Liu, Shasha, Wang, Xianfeng, Zou, Chengyue, Zhou, Jun, Yang, Mei, Zhang, Suyi, Huo, Danqun, Hou, Changjun
• Format: Article
• Language: English
• ISSN: 1873-4324
• DOI: 10.1016/j.aca.2020.12.016

Hexavalent chromium ion (Cr ) is highly toxic to human health and environment. Herein, high-performance detection of Cr is of great import. In this study, a rapid and sensitive multicolor colorimetric method for detection of Cr in aqueous solution was established on the basis of Cr etching of gold nano-double cone@silver nanorods (Au NDC@Ag NRs). Au NDC@Ag NRs was synthesized by a modified seed-mediated growth method. The catalytic etching induced by Cr changed the morphology of Au NDC@Ag NRs, leading to the attenuation of surface plasma resonance (SPR) and the redshift of absorption spectra. Meanwhile, Au NDC@Ag NRs exhibits obvious color changes from orange to pink, to purple, and finally becomes colorless with the increasing concentrations of Cr . With such a design, naked-eye detection of Cr was realized with high sensitivity. The proposed multicolor sensing method showed a good linearity between the redshift change of absorption peak (△λ) and the concentrations of Cr in the range from 2.5 to 40 μM. The limit of detection (LOD) was calculated as 1.69 μM in aqueous solution. In addition, successful detection of Cr in tap water and Yangtze River water, indicating the real applications of Au NDC@Ag NRs probe in monitoring Cr in environment.