Evaluation of the SERS performances of Tabun and VX label-free detection in complex and multicomponent fluids

Nerve agents represent a serious threat to security worldwide. Chemical terrorism has become an alarming danger since the technological progresses have simplified the production of nerve agents. Therefore, there is an immediate demand for a fast and precise detection of these compounds on-site and real-time. In this perspective, Surface-Enhanced Raman Scattering (SERS) has emerged as a well-suited alternative for on-field detection.SERS performances of unfunctionalized SERS substrates were evaluated in realistic samples. Two nerve agents, Tabun and VX, were diluted in two matrix models: a contact lens solution, and a caffeine-based eye serum. The performance two research-grade instruments and two portable devices were compared. Despite the use of a small sampling volume of complex matrices without any sample pre-treatment, we achieved Tabun detection in both media, with a practical limit of detection (LOD) in the range of 7–9 ppm in contact lens liquid, and of 10.2 ppm in eye serum. VX detection turned out to be more challenging and was achieved only in contact lens solution, with a practical LOD in the range of 0.6–5 ppm.These results demonstrate the feasibility of on-field detection of nerve agents with SERS, that could be implemented when there is suspicion of chemical threat.