SERS-based ultrasensitive detection of organophosphorus nerve agents via substrate's surface modification.
Highly efficient detection of the organicphosphor nerve agents such as sarin and soman, based on surface enhanced Raman scattering (SERS) effect, has been in challenge due to their weak adsorption property on coin metals. In this paper, a new strategy is presented to achieve the SERS-based ultrasensitive detection of sarin-simulated agent methanephosphonic acid (MPA) via the surface modification of SERS-substrates. The Au-coated Si nanocone array is surface-modified with 2-aminoethanethiol and used as SERS-substrate for detection of MPA. It has been shown that the modified substrate could preferentially capture MPA molecules in the solution with coupling agent and induce amidation reaction. The reaction products are still bound or anchor on the substrate's surface. The MPA molecules can thus be detected by Raman spectral measurement of the solution-soaked SERS-substrate. The minimum detection level is down to ∼1ppb. The Raman peak intensity versus the MPA concentration is subject to a linear double logarithmic relation from ∼1ppb to ∼1000ppm, which is attributed to Freundlich adsorption of MPA on the surface-modified SERS substrate. This study provides a new way for the highly efficient SERS-based detection of the organophosphorus nerve agents and some other target molecules weakly interacted with metal substrates.
Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China; University of Science and Technology of China, Hefei 230026, PR China.
Qian
Q
Zhao
Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China. Electronic address: liugq@issp.ac.cn.
Guangqiang
G
Liu
Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China.
Hongwen
H
Zhang
Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China.
Fei
F
Zhou
Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China.
Yue
Y
Li
Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China; University of Science and Technology of China, Hefei 230026, PR China. Electronic address: wpcai@issp.ac.cn.
Weiping
W
Cai
D000327:Adsorption; D003543:Cysteamine / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D000067397:Nerve Agents / Q000032:analysis* / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000032:analysis* / Q000737:chemistry; D012825:Silicon / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
D000067397:Nerve Agents; D009943:Organophosphorus Compounds; D003543:Cysteamine; D006046:Gold; D012825:Silicon
Amidation reaction; Metal- weakly interacted molecules; Nerve agents; SERS-based detection; Surface modification