Stability of polymer films. Resonant frequency changes for the binding of BtOMe to the MIP film after prolonged storage in the dry state. Analyte concentrations used were 10 mM (red), 7.5 mM (green), 5 mM (black), 4 mM (yellow) and 2 mM (pink). Calibration was carried out on one MIP film at specified time intervals after fabrication (6 injections for one surface). Inset shows the sensor response for BtOMe (5 mM) injections under continuous flow (20 μL/min) after 0, 24, and 48 h.