Mechanistic model of diffusion and reaction in thin sensor layers—the DIRMAS model

For a better understanding and prediction of the sensor behaviour the mechanistic model DIRMAS (Diffusion and Reaction Model of Analytes in Sensor) layers was developed. Quartz microbalance sensors measure the mass increase of a sensitive layer caused by the absorption of analytes. In order to detect analytes which are minor components of a complex gas mixture the sensitive layers should be highly selective to these analytes. However, a high selectivity often results in slow kinetics of the absorption/desorption process. A better understanding of the kinetic reaction can help to design optimised layers and to decrease analysis time.