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 10 mu g . 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 10 mu g . 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.
