Trends in microwave spectroscopy for the detection of chemical agents

Recent developments in microwave spectroscopy have encouraged researchers to develop this technique for analytical applications such as environmental monitoring, industrial process control, and homeland defense. This paper presents a general overview of microwave spectroscopy with a focus on aspects relevant for detecting chemical warfare agents (CWAs) and their surrogates. In particular, the high spectral resolution of microwave methods provides exceptional selectivity which is critical for detecting and identifying CWAs given the complex environments and numerous interferents that may obscure measurements by instruments with poor specificity. Ongoing efforts to develop a microwave spectral database of CWAs and improve the quantitative capabilities of Fourier transform microwave spectrometers are discussed. Additionally, future improvements to achieve a field-deployable sensor are presented.