The improved ammonia gas sensors constructed by l-glutamic acid hydrochloride on surface acoustic wave devices

The gas sensing properties of l-glutamic acid hydrochloride deposited onto 128° YX-LiNbO3 surface acoustic wave (SAW) delay line are monitored in this study. The sensitivity, response time, reversibility, repeatability, selectivity, and long-term stability of l-glutamic acid hydrochloride are also investigated. The SAW gas sensors based on l-glutamic acid hydrochloride exhibit good sensitivity and reversibility towards ammonia gas, and the results are highly repeatable. The detection limit of l-glutamic acid hydrochloride has been found to be less than 0.90 ppm ammonia in air. l-Glutamic acid hydrochloride has been observed to have an excellent transient response. Moreover, the selectivity of l-glutamic acid hydrochloride to ammonia is good. The long-term stability of l-glutamic acid hydrochloride is also stable. The response degrades at a rate of 0.01 ppm per day.