HF-QCM combines QCM technology with plasma etching, chemical coatings, micromechanics, and digital data processing. Chemical coatings are designed to react with chemicals of interest, and coated onto the sensors. Based on piezoelectric theory, when a chemical reacts, or is absorbed by the coating, it changes the mass of that coating, and in turn affects the resonating frequency. The change in frequency is dependent on mass of the chemical that interacts with the coating. It is this change in frequency that is detected. Multiple sensors are placed into an array to allow for higher selectivity, and to allow for the detection of multiple target chemicals.
Advantages: Small size, easy to train and operate.
Limitations: Only detect materials in library, new technology with limited library, after continual use HF-QCM array replacement is necessary.