Investigation of ITO based liquid sensor for ammonia hydroxide detection
  We proposed an Indium Tin Oxide (ITO) sensor for detecting the NH4OH in seawater and carried out a series of experiments to investigate the feasibility of it as a hazardous and noxious substance (HNS) sensor. The ITO layer revealed a distinct resistance change ({\delta}R) which is linearly correlated with the NH4OH concentration. Sensing mechanism of the porous ITO layer has been explained in terms of reduction and electrical double layer (EDL) formation. Also, the chemical stability of ITO as a HNS sensor has verified. 
Seok-hwan Lee, Jung-Yeul Jung, Moonjin Lee and Jiho Chang
cond-mat.mtrl-sci