Colorimetric/SERS dual-mode detection of mercury ion via SERS-Active peroxidase-like Au@AgPt NPs

The development of mercury ion (Hg2+) probes integrating the ability of facile preliminary evaluation and high-sensitive accurate assay with wide detection range is very important for water pollution prevention and human health. Herein, a novel colorimetric/SERS dual-mode detection of Hg2+ was proposed by using the SERS-active peroxidase-like Au@AgPt NPs. The Au@AgPt NP has hexoctahedral Au nanoparticle core with edges coating by Pt, which shows good SERS activity of Au and enhanced catalyst activity of Pt for designing colorimetric/SERS dual-mode probes. Basing on the colorimetric assay, 5 mu M-1 mM Hg2+ can be facile observed by naked eye and a linear sensing (1 mu M-100 mu M) with limit of detection (LOD) of 0.52 mu M was obtained by absorption analysis. Besides, a linear calibration curve from 1 mu M to 10 mu M was achieved by SERS with LOD of 0.28 nM. The proposed dual-mode probes with good selectivity and reliability integrate the advantages of facile detection by colorimetric analysis and high-sensitive trace assay by SERS, and possess relatively better performance on sensitivity and detection range in comparison to the previous probes/methods, which can be served as efficient probes for monitoring water quality.