Detecting mustard gas using high Q-value SAW resonator gas sensors

Surface acoustic wave (SAW) resonator gas sensors have been applied in many fields for the advantages of high Q-value and low insertion loss, but seldom used in chemical warfare agents detection. In this paper, a novel SAW gas sensor with high Q-value for mustard gas (HD, a blister agent) detection was developed. The sensor was a two-port SAW resonator device using polished ST-quartz substrates with a fundamental frequency of 200 MHz. The sensors with polyepichlorohydrin (PECH) as the sensitive coating of HD were prepared by spin-coating method. Such sensor kept the high Q-value, low insertion loss and showed very high stability in air stream. Based on such sensors and a gas generation system, the flowing detection method of HD was built. The results showed that such sensor could be used repeatedly, the sensitivity was 106 Hz/(mg/m³), the linear relationship ranged from 1.2-61.6 mgmiddotm^-3(r=0.9977) and the detection limit reached 0.3mgmiddotm^-3(S/N=3). In the sampling and purging period, the rate of recovery was up to 90%, the RSD of the responses was less than 5% in more than ten detection cycles. Moreover, the components of the air and other organophosphate nerve agents had no obvious effect on the response. Such performances showed the SAW sensors could be beneficial for chemical warfare agents detection.