QCM Measurements in Newtonian Liquids: Problems and Performance Analysis

The article provides an overview of the measurement issues affecting sensing systems based on quartz crystal microbalances (QCM), operating in liquids. The article analyzes the effect of the presence of a viscous liquid at the interface with the QCM sensors by analytical models and experimental tests based on impedance measurements in reference conditions. The study takes also into account the parasitic effects due to the measurement setup and provides results, which can be applied to a wide range of scenarios also in the presence of highly viscous media. The article also presents a model-fitting procedure for QCM impedance spectra, which provides accurate estimations of the electromechanical parameters.