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Terahertz (THz) spectroscopy is a rapidly emerging technology in the field of analytical chemistry. THz spectroscopy shows substantial scientific potential given that numerous absorption and emission molecular lines of interest in the chemical sciences belong to this spectral region. This article focuses on the current research progress on the detection of harmful gases, pesticides, antibiotics, toxic chemical compounds, and drugs of abuse by THz spectroscopy. The article also analyzes the key factors used for the detection of toxic chemical compounds by THz spectroscopy.

Purpose This paper aims to give an overview about the state of wireless passive surface acoustic wave (SAW) gas sensor used in the detection of chemical vapor. It also discusses a variety of different architectures including delay line and array sensor for gas detection, and it is considered that this technology has a good application prospect. Design/methodology/approach The authors state the most of the wireless passive SAW methods used in gas sensing, such as CO2, CO, CH4, C2H4, NH3, NO2, et al., the sensor principles, design procedures and technological issues are discussed in detail; their advantages and disadvantages are also summarized. In conclusion, it gives a prospect of wireless passive SAW sensor applications and proposes the future research field might lie in the studying of many kinds of harmful gases. Findings In this paper, the authors will try to cover most of the important methods used in gas sensing and their recent developments. Although wireless passive SAW sensors have been used successfully in harsh environments for the monitoring of temperature or pressure, the using in chemical gases are seldom reported. This review paper gives a survey of the present state of wireless passive SAW sensor in gas detection and suggests new and exciting perspectives of wireless passive SAW gas sensor technology. Research limitations/implications The authors will review most of the methods used in wireless passive SAW sensor and discuss the current research status and development trend; the potential application in future is also forecasted. Originality/value The authors will review most of the methods used in wireless passive SAW sensor and discuss the current research status and development trend; the potential application in future is also forecasted.

In this study, diisopropyl methylphosphonate (DIMP), tributyl phosphate (TBP), and dimethyl methylphosphonate (DMMP) were selected as organophosphorus chemical warfare agent (CWA) simulants.

The uniformity and compactness of the surface of a viscoelastic sensitive film are among the most important factors that influence the characteristics of a surface acoustic wave (SAW) gas sensor....