A Preliminary Study On The Application Of Surface-enhanced Raman Spectroscopy In The Field Of National Defense Security

Chemical Warfare Agents(Chemical Warfare Agents,CWAs)are a kind of highly toxic and dangerous chemicals,which are often used in the military field as chemical weapons to kill the enemy’s active forces.However,incidents of chemical warfare agents poisoning have occurred frequently in partial wars and terrorist attacks.Therefore,it is of great practical significance to develop and establish a highly sensitive,rapid,and accurate real-time detection technology for chemical warfare agents.Considering the extremely strong toxicity of chemical warfare agents and the need to achieve rapid qualitative and highly sensitive detection of chemical warfare agents,this study uses mustard gas and neurotoxic simulants as the target molecules,based on surface-enhanced Raman spectroscopy(Surface-enhanced Raman spectroscopy,SERS)technology,try to establish a simple and rapid analysis and detection method in the sol and solid substrate systems respectively.The main work includes the following three parts:(1)Preliminary study on SERS detection in sol system.The effects of the competition and co-adsorption behavior of the agglomerates anion and the target molecules on the surface of the SERS substrate on the SERS detection sensitivity of the target molecules were investigated systematically.By regulating the intermolecular interaction,the μg/L level mustard gas simulant 2-chloroethyl ethyl sulfide(2-CEES)and the mg/L level tabun(GA)simulant diethyl cyanophosphate are realized(DECP)Highly sensitive detection.(2)Preparation and SERS detection of solid substrate with micro-nano structure.In response to the fool’s rapid detection requirements for chemical warfare agents in modern warfare,the development of a highly sensitive and stable SERS solid substrate was carried out,and its detection sensitivity to chemical warfare agent simulants was preliminarily investigated.In order to construct a three-dimensional ordered SERS "hot spot",we used a combination of laser etching and nano-particle multilayer self-assembly to prepare a three-dimensional solid-state SRES substrate with high assembly density and regularity.By adding low-concentration halogen salts to effectively remove citrate and other impurities existed in the substrate preparation process,the effective detection of mg/L sarin(GB)simulant dimethyl methyl phosphate(DMMP)and soman(GD)diethyl chloromethyl phosphate(DECMP)has been achieved.(3)From the laboratory to the scene to the vehicle to the individual.In response to the urgent requirements of modern warfare for the portability of detection equipment and rapid on-site operation,the vehicle-mounted portable and individual hand-held Raman spectrometer was used as the hardware carrier to investigate its detectability level for four simulant molecules.The results show that the SERS spectrum results obtained on the large-scale and portable Raman spectrometers maintain a high degree of consistency,and the characteristic peaks are not significantly shifted,which verifies the accurate recognition ability of the vehicle-mounted Raman instrument.However,with the miniaturization of Raman instruments,the minimum detectable concentration of the simulant standard solution gradually increases,and the sensitivity loss caused by the miniaturization of the instrument cannot be ignored.Nevertheless,the detection sensitivity of the SERS method established in this paper still basically meets the actual field requirements.