Quartz microbalances (piezoelectric microweighting, English quartz crystal microbalance, quartz crystal nanobalance, QCM, QCN ) is a mass measurement tool whose principle of operation is based on the dependence of the oscillation frequency of a quartz resonator (microbalance sensor) on the mass of a substance deposited on its surface.
Description
The basis of the quartz microbalance is a quartz plate, cut from a single crystal of quartz at a certain angle. Gold electrodes are applied above and below this plate. When an alternating voltage is connected to these electrodes, the plate begins to oscillate due to the phenomenon of the inverse piezoelectric effect. At a certain frequency of an alternating voltage in such an oscillatory system, resonance occurs. When a substance is deposited on the surface of this device, the resonant frequency of the plate changes, on the basis of which the mass of the deposited substance is calculated.
Application
Due to the fact that quartz microbalances can work not only in vacuum and in air, but also in liquids, they are widely used in biochemistry . For example, by immobilizing on the surface of the weights recognizing biomolecules that specifically capture the detected substance from the solution, one of the biosensor variants is obtained. The most common immunobiosensors that recognize antibodies , and DNA biosensors that recognize short fragments of DNA or RNA.