Quartz crystal microbalance coated with poly-L-proline self assembly layer to detect organic gases

A gas sensor system using the assembled molecular layer of poly amino acid derivative, poly-L-proline has been developed. The thin layer was prepared using self assembly technique which was deposited onto a quartz crystal microbalance (QCM) substrate. The QCM coated self-assembly monolayer (SAM) was used to detect the presence of two vapor samples; saturated vapor of acetone and 2-propanol. The sensing sensitivity was based on the change in the fundamental frequency of the QCM upon exposure towards gas sample. It was found that the SAM-coated QCM sensor system was sensitive towards the vapor samples by reducing its fundamental frequency. It was also found that the SAM exhibited a good stability and reproducibility behaviors.