Comparison of Two Methods to Reduce Time Measurement of Quartz Crystal Microbalance Gas Sensors

The present work involves a comparison of two methods for the reduction of the measurement time of the response of gas sensors based on quartz crystal microbalance. The measurement time reduction was achieved by the prediction of the steady-state response. The successive fittings method was used to predict the steady-state sensor response based on an analysis of the transient response using a bi-exponential model. On the other hand, The Exponential Moving Average (EMA) method was used to obtain a characteristic at a time instant in the early transient response, before the steady-state magnitude of the sensor was reached. A comparison between the results obtained from the two methods was performed. Although the EMA method predicts the sensor response in a lesser time than the successive fittings one, the latter allows to obtain other parameters such as the sensor steady-state magnitude and the time constants. The results obtained showed that both methods are suitable to reduce the measurement time and can be combined to generate a most effective prediction of the gas sensor response.