A quartz crystal microbalance modified with carbon nanotubes as a sensor for volatile organic compounds

A piezoelectric quartz crystal microbalance (PQCM) was modified with multi-walled carbon nanotubes (MWCNTs) to develop a chemically based sensor for measurements other than the typical mass change in the quartz crystal. Slight conductivity changes in the carbon nanotubes are amplified to obtain a vibrational frequency signal in the crystal. A commercially available quartz crystal microbalance was modified by replacing its electrode with MWCNTs to obtain a sensor with high sensitivity, selectivity, robustness and stability over time. The modified microbalance was successfully used to determine various types of analytes including volatile organic compounds (VOCs), aldehydes and amines.