表面增强拉曼光谱技术快速检测神经性化学毒剂模拟剂

神经性化学毒剂具有毒性高、挥发性好和作用快等特点，在浓度很低的情况下就可以造成很大的伤亡，因此成为现场快速检测的难点。而化学毒剂沙林（甲氟膦酸异丙酯，GB）是一种经常用的军事神经性毒剂，该毒剂可通过抑制乙酰胆碱酯酶来破坏神经系统的功能，同时该毒剂被吸入后在人体内的降解速度很慢。为了避免和降低该类毒剂的污染和对人员伤害，迫切需要发展一种灵敏度高、准确性好、响应时间短和可便携化的检测技术检测GB。表面增强拉曼光谱(SERS)检测方法具有灵敏度高、操作简单和响应速度快的特点，成为检测水中痕量化学毒剂的有效方法之一。将购买的Ag纳米溶胶进行离心，然后将其组装固定在硅基Au膜表面从而制备高SERS增强的基底来对化学毒剂模拟剂甲基磷酸二甲酯（DMMP）的快速检测方法进行研究。在实验中，通过优化团聚剂的离子强度、测试方法等来对检测条件进行优化筛选。通过对比不同的团聚剂HCl，KI，MgSO₄，NaCl和NaOH，最终得到最优的离子强度，从而确定1 mol·L-1的KI为团聚剂时具有最好的效果。分别对不同的检测方法来进行了相应的优化，通过对比芯片法和液态溶胶法，最终发现改进后的芯片法能够获得较好的检测效果。最终确定的检测方法为将1 mol·L-1的KI和待测溶液（DMMP）混匀，然后滴在事先准备的以Ag纳米溶胶为基质制得的SERS芯片上，用波长为785 nm激光的便携式拉曼光谱仪直接进行检测，最低可以测至10 μg·L-1。而在文献资料中报道美军短期（＜7 d）饮用水最大暴露安全指南规定对神经性化学毒剂最低检出限是10 μg·L-1，因此采用该SERS检测方法，满足了军队应对化学战或者恐怖袭击的行动的需要。实验结果表明该方法突破了便携拉曼光谱仪灵敏度低的局限，解决了痕量神经性毒剂现场快速检测难题，拓展了SERS技术在化学侦察领域的应用。

Rapidly Detection of Chemical Warfare Agent Simulants by Surface Enhanced Raman Spectroscopy

Nerve chemical agents have the characteristics of high toxicity,good volatility and fast action,which can cause great casualties in the case of low concentration,so it becomes difficulty to rapid detection in the field.The chemical poison Sarin(Isopropyl Mefluronate,GB)is a commonly used military neurotoxic agent,which can destroy the function of the nervous system by inhibiting acetylcholinesterase,and the degradation rate in the human body is very slow.Based on this,to avoid and reduce the pollution of such poisons and harm to personnel,it is urgent to develop a detection technology with high sensitivity,good accuracy,short response time and portability to detect GB.There are many methods for detecting chemical poisons and their simulants,including spectroscopy,chromatography,surface acoustic wave(SAW)sensors and so on.However,the above methods generally have long response time,poor accuracy,and low detection sensitivity.Therefore,the development of a highly sensitive,simple and fast spectroscopic technique to detect GB has become an important task in chemical weapons detection.Surface-enhanced Raman spectroscopy(SERS)is one of the effective methods to detect trace chemical agents in water due to its high sensitivity,simple operation and fast response time.In this paper,the purchased Ag nano-sol is centrifuged and then assembled on the surface of the silicon-based Au film to prepare a high SERS enhanced substrate to quickly detect the chemical toxicant simulant dimethyl methyl phosphate(DMMP).In the experiment,the detection conditions were optimized and screened by optimizing the ionic strength of the agglomerating agent,test methods and other conditions.By comparing different agglomerating agents HCl,KI,MgSO₄,NaCl and NaOH,the optimal ionic strength is finally obtained,and it is determined that 1 mol·L^-1 KI has the best effect as the agglomerating agent.In addition,different detection methods were optimized accordingly.By comparing the solid substrate method and the liquid sol method,it was finally found that the improved chip method can obtain better detection results.The final detection method is to mix 1 mol·L^-1 of KI with the solution to be measured(DMMP),and then drop it on a pre-prepared SERS chip made of Ag nano-sol as a matrix,using a portable laser with a wavelength of 785 nm Raman directly performs detection,and it can measure as low as 10μg·L^-1.However,it is reported in the literature that the US military’s short-term(less than 7 days)drinking water maximum exposure safety guidelines stipulate that the limit of detection for neurochemical poisons is 10μg·L^-1.Therefore,using this SERS detection method meets the military’s response to chemical warfare or The need for terrorist attacks.The experimental results show that this method breaks through the limitation of the low sensitivity of portable Raman spectrometer,solves the problem of rapid detection of trace nerve agents on-site,and expands the application of SERS technology in the field of chemical reconnaissance.