A study of quartz crystal microbalance modified with polyvinyl acetate nanofiber to differentiate short-chain alcohol isomers

The detection of short-chain alcohols and their isomers in the atmosphere remains a challenge in solving environmental, occupational safety, and health issues. We report on the sensing of isomers of butanol by quartz crystal microbalance (QCM). QCM chips were coated with polyvinyl acetate (PVAc) nanofibers through the electrospinning technique. The produced PVAc nanofibers were confirmed using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Four isomers of butanol, i.e., butan-1-ol, 2-methylpropan-1-ol, butan-2-ol, and 2-methylpropan-2-ol, were used in this study. The results indicate that the structures of the isomers of butanol affect the sensitivity of the QCM PVAc nanofiber sensor. Butan-1-ol that has the lowest vapor pressure exhibits the highest frequency shift. Linear butanol molecules exhibit a higher sensitivity than that of branched butanol molecules because of the ease of intermolecular interaction with nanofibers. These findings provide additional information on the interaction between the analyte and the active layer in QCM-based gas sensing. Notably, the QCM PVAc nanofiber sensor is clearly able to differentiate four isomers of butanol, which may be used in developing a promising new method for structural isomer identification.