9.2.1.   Single Analytes

The sensor responses for the measurements of different concentrations of the 3 analytes are plotted in figure 16 (section 4.5.2.2) during 600 seconds of sorption and a subsequent desorption. The sensor reacts spontaneously to the presence and absence of methanol vapors resulting in a rectangular shape along the time axis. The sensor response for ethanol is slower resulting in shapes, which are more curved, whereas the sorption of 1-propanol into the sensitive polymer layer is very slow not reaching equilibrium between the vapors of 1-propanol and the 1-propanol sorbed into the polymer layer. Therefore, the shape of the sensor response for 1-propanol does not reach a plateau during sorption and the signals need a long time to come down to the baseline during desorption.