Compensation of Temperature Variations in Chemcapacitive Gas Sensing Systems

Laboratory evaluation of gas sensing systems is usually performed under well-controlled experimental conditions. However, in real applications, environmental parameters, such as temperature and humidity, are likely to be unstable. In this work, the effect of temperature variations ranging from 0.5-3 degrees C, on the signal of a chemocapacitor sensor array, equilibrated at different levels of relative humidity is studied. Accurate recording of temperature concurrently to the capacitance signal of the sensors enabled us to develop a temperature (Delta T)-capacitance (Delta C) calibration curve for each sensor. The linear Delta C-Delta T relations were found to depend on the specific polymeric sensing layer, and were then used to demonstrate the importance of the said correction in Volatile Organic Compounds (VOCs) sensing in humid environment and under relatively unstable temperature conditions. Additionally, the sensors response under static and under dynamic headspace conditions was compared.