Four-Channel Monitoring System with Surface Acoustic Wave Sensors for Detection of Chemical Warfare Agents.

Recently, efforts have been made to adapt surface acoustic waves (SAWs) for use in chemical sensors for detection of chemical warfare agents (CWAs). In this study, a four-channel real-time CWA detection system was constructed using four 250-MHz SAW sensors. Each system consists of three different chemical sensors and one reference sensor.

Improved Performance of Surface Acoustic Wave Sensors by Plasma Treatments for Chemical Warfare Agents Monitoring.

The effects of a plasma treatment on the sensing performance of surface acoustic wave (SAW) sensors to detect chemical warfare agents (CWAs) were investigated. SAW sensors designed for an operating frequency of 250 MHz were fabricated using lift-off techniques followed by the deposition of a very thin thiourea (TU) layer as a sensing film on the sensing area of the SAW sensor. To achieve some advantages from the plasma treatment on the surface, such as cleaning, surface activation and modification, a post-plasma treatment was performed on the sensing layer and the sensing performance of the SAW sensor was measured by a comparison with the measured responses, providing different simulant gases through the gas feeding system.

Binding thiourea derivatives with dimethyl methylphosphonate for sensing nerve agents.

In an effort to develop efficient substrates to sense organophosphonate nerve agents, we used the density-functional theory calculations to determine binding energies and geometries of 1 : 1 complexes formed between dimethyl methylphosphonate (DMMP) and 13 thiourea derivatives (TUn), including four newly-synthesized ones (n = 10-13). The four new thiourea derivatives have a 3,5-bis-(trifluoromethyl)phenyl group as one -substituent and an alkylphenyl group with zero to three methylene linkages as the other -substituent. The calculated geometries show that intermolecular double H-bonding is the most important factor influencing the formation of stable complexes at the molecular level.

Structural Effect of Thioureas on the Detection of Chemical Warfare Agent Simulants.

The ability to rapidly detect, identify, and monitor chemical warfare agents (CWAs) is imperative for both military and civilian defense. Since most CWAs and their simulants have an organophosphonate group, which is a hydrogen (H)-bond acceptor, many H-bond donors have been developed to effectively bind to the organophosphonate group. Although thioureas have been actively studied as an organocatalyst, they are relatively less investigated in CWA detection.