microbalances

Microbalances are highly sensitive instruments designed to measure very small masses, typically from the microgram to the nanogram range. They are employed in surface science, materials research, and biosensing to quantify adsorption, thin-film growth, and binding events on solid surfaces, as well as gas sorption and catalysis studies.

Most microbalances convert a mass change into a measurable signal. The quartz crystal microbalance (QCM) is common: a thin quartz plate is driven to resonance, and added mass lowers the frequency. For rigid, uniform films, the Sauerbrey equation relates mass change to frequency shift. Variants such as QCM-D also monitor energy dissipation to assess viscoelastic properties. MEMS-based microbalances use microfabricated cantilevers or resonators, enabling compact, real-time mass sensing in vacuum or liquid environments.

Applications span surface adsorption studies, thin-film deposition, corrosion monitoring, and real-time biosensing of biomolecular interactions. Advantages include high sensitivity and real-time data; limitations include assumptions about film rigidity and the influence of environmental damping, especially in liquids. Calibration and proper modeling are essential for quantitative results. Microbalances continue to play a key role in materials characterization, catalysis research, and biosensing platforms.