This definition appears very rarely
Samples in periodicals archive:
Quartz Crystal Microbalance for thin film deposition, Quarz Mikrowaage
Quartz Crystal Microbalance: Gamry eQCM 10M: QCM/Electrochemical Quartz Crystal Microbalance-Corrosion Studies,Electroactive Polymers.
The Model 400 series is a combination between quartz crystal microbalance (QCM) and electrochemistry (EQCM). The quartz crystal microbalance is a variant of acoustic wave microsensors that are capable of ultrasensitive mass measurements. Under favorable conditions, a typical QCM can measure a mass change of 0.1-1 ng/cm2.