In this work the authors propose the development and the characterization of two NO2 amperometric detection systems, based on two different solid state electrochemical sensors. Both sensors have a Nickel Oxide counter electrode, a Graphite working electrode, and Nafion as protonic conductor. The first detection system exploits a two-electrode sensor that presents a satisfactory sensitivity to NO2, a very low cross-response to interfering gases (CO, O2), a short response time, and that requires simple front-end electronics. Nevertheless, the usage of this sensor is limited to the detection of low NO2 concentrations (below 10 ppm). A similar performance can be obtained by a system based on a three-electrode version of the sensor which can be used in a wider NO2 concentration range, but requires a more complex front end electronics
