Carbonate based CO2 sensors with high performance

Comparison of three different sodium carbonate based sensor types shows that sensors with solid state references have a nearly drift-free response to CO 2 changes (drift <0.5 mV/24 h). Gases as H 2 O (max. 50% r.h.), CO (max. 30 ppm), CH 4 (max. 200 ppm) had no significant influence on the performance of all sensor types. Small amounts of NO 2 (100 ppm) led to a (reversible) disturbance of the sensor signal only if the reference electrode is not sealed. It is shown that sensors with encapsulated solid state references resist to SO 2 concentrations lower than 500 ppb because the formation of stable sodium sulfate is kinetically hindered.