Most techniques for ammonia detection, such as infrared analysis or optical gas sensors require sophisticated expensive instrumentation and are not suitable for on-site measurement [7–9]. On the contrary, electrochemical gas sensors operate with minimal instrumentation, are economical and yet have high precision levels [28]. Also the majority of studies carried out so far have been focused on the development of either potentiometric or amperometric based sensors [29]. Electrical impedance spectroscopy (EIS), has hitherto been explored only to a very limited extent. There have been some EIS studies on the inductive behavior of PANI owing to degradation during its polymerization [30] and on the corrosion resistance of PANI as a protective coating layer [31]. Application of EIS as a sensor tool using PANI as the base polymer has been carried out in dodecatungstophosphoric acid doped and undoped PANI intercalated polyoxomolybdate matrices for sensing of acetone vapor [32,33]. There has been some other works using AC impedance analysis for antibody detection in competitive electroimmunoassay [34]. A notable EIS study was carried out in 1996 using PANI as the sensing material for methanol and acetone. The impedance loci were used to extract the resistive and reactance components and a circuit modeling study was carried out on the impedance data [35]