Electrolytic sensor for trace level determination of moisture in gas streams

A thin film platinum electrode-based electrolytic moisture sensor for the measurement of lower concentrations of moisture in gas streams with flow rates lesser than 5 ml/min was designed. The thin film electrode was fabricated with pulsed laser ablation technique and screen printing. The PL-ablated electrode showed deterioration after 80 h of operation. The screen-printed thick film electrode sustained for more than 12 months. The response of the sensor was absolute and so the electrolytic and non-electrolytic currents were deduced. The sensor recovery time from either extreme dry or moist conditions was 70 s. The concentration of trace moisture in an argon cylinder was identified using the present design and the values were found to be 3.97 ± 0.07 ppm at cylinder pressure of 150 kg/cm2 and 37.41 ± 0.27 ppm at 30 kg/cm2. In addition to the sensitivity up to 1 ppm the present design could detect the sensor failure during operation.