QUARTZ CRYSTAL MICROBALANCE (QCM) & EQCM

A quartz crystal microbalance (QCM) measures a mass variation per unit area by measuring the change in frequency of a quartz crystal resonator. The resonance is disturbed by the addition or removal of a small mass due to oxide growth/decay or film deposition at the surface of the acoustic resonator. The QCM can be used under vacuum, in gas phase and liquid environments. It is useful for monitoring the rate of deposition in thin film deposition systems under vacuum. In liquid, it is highly effective at determining the affinity of molecules (proteins in particular) to surfaces functionalized with recognition sites. Larger entities such as viruses or polymers are investigated as well. QCM has also been used to investigate interactions between biomolecules.

The QCM can be combined with other surface-analytical instruments. The electrochemical QCM (EQCM) is particularly advanced. Using the EQCM, one determines the ratio of mass deposited at the electrode surface during an electrochemical reaction to the total charge passed through the electrode. This ratio is called the current efficiency.

RotaLab provides state-of-the-art QCM system to determine a small mass change by measuring resonance frequency, while simultaneously determining viscoelastic change by measuring resonance resistance. Our QCM monitors the resonant frequency of a Pt or Au coated AT-cut quartz crystal. It can also be used in conjunction with our potentiostats from Princeton Applied Research for EQCM applications.