Quartz Crystal Microbalance
The Quartz Crystal Microbalance (QCM) is a highly sensitive mass measuring system based ond the principles of piezoelectricity. The sensor quartz crystal, with gold electrodes on both sides, is brought into high frequency oscillation by applying alternating current. The frequency of this oscillation is perturbed if there is a mass change on the surface of the crystal. If mass is deposited on the crystal, the thickness increases, resulting in a decrease in resonant frequency. The mass changes can be determined from the measured frequency changes with a resolution of less than 0.1 ng/cm2. This high sensitivity makes the QCM a suitable method for the studying of adsorption kinetics, thin film deposition, surface -, electrochemical -, biochemical reactions.
