The detection properties of ammonia SAW gas sensors based on L-glutamic acid hydrochloride

This study has investigated an improved surface acoustic wave (SAW) ammonia gas sensor based on L-glutamic acid hydrochloride. It presents an excellent reversibility, sensitivity, and repeatability to ammonia. The frequency shift versus ammonia concentration above 40/spl deg/C was a monotonic function, and the limit of detection of the sensor at 50/spl deg/C was 80 ppb.