An Electrochemical Ammonia Sensor on Paper Substrate

In this article, a room temperature ammonia sensor on a paper substrate is reported. The electrochemical sensor is constructed using platinum electrodes and ionic liquid electrolyte. The amperometric staircase response shows discernible signal differentiation between each concentration of NH 3 (5–25 ppm). The rise time and fall time for the NH 3 sensor were found to be 8 s and 7 s respectively. The authors believe such a fast responding NH 3 sensor on a paper substrate has never been reported. The detection limit was deduced to be 1 ppm based on the sensitivity versus concentration plot. A 17% decrease in sensor response was observed over 30 days of testing. Implementing an antenna on the paper substrate co-located with the sensor for wireless operation is envisioned in future.