Quartz Crystal Microbalance with Dissipation Monitoring
The Quartz Crystal Microbalance (QCM) is a mass-type transducer, which uses acoustic transducers, i.e. piezoelectric crystals. The crystal has a characteristic resonance frequency that depends on its mass. Additional mass deposited on its surface will cause a change in the resonant frequency (F), and this change will be proportional to the mass accumulated. It obtains its chemical sensitivity and selectivity from a chemically active coating, which interacts with the surrounding environment. Analyte adsorption in the sensitive layer results in a change in the resonator's frequency.
In the JRC laboratory we have a Q-sense E4 system (Q-Sense, Sweden), which employs the QCM-D technique, measuring both the resonant frequency (F) and the dissipation energy (D) of the resonator. The simultaneous measurement of F and D allows to study of the viscoelastic properties of the added layer in detail, by means of a modelling software. We use this technique to study the interaction between biomolecules and functionalized surfaces.