Optimization of QCM sensor for BTX detection

Developing a sensitive, low-cost sensor for detecting hazardous volatile organic compounds in an indoor and outdoor environment for industrial application is an important area of research. Increased Oil and Gas industrial activities have resulted in abundant harmful volatile organic compounds in the atmosphere, such as Benzene, Toluene, and Xylene (BTX). The study aims to optimize polyvinyl acetate (PVAc) coating onto the Quartz Crystal Microbalance (QCM) sensor surface for BTX detection. The thickness of the PVAc film was altered with different spin-coating speeds. The effect of different film thicknesses on the QCM response is examined through various characterization techniques and experimental approaches (sensitivity, repeatability, and reproducibility). Principal Component Analysis (PCA) and K-means clustering were applied for data analysis. The rough surface morphology of PVAc in the SEM micrograph provides abundant active sites for stronger interactions with nonpolar BTX gases. The fabricated QCM sensor showed good sensitivity of 0.109 Hz/ppm for Benzene, 0.175 Hz/ppm for Toluene, and 0.23 Hz/ppm for Xylene for QP1500 spin-coated thickness. Clustering analysis revealed distinct BTX concentration clusters, supported by a silhouette score of 0.57, indicating successful discrimination. Also, the QCM sensor with PVAc coating presented in this study had decreased fabrication complexity.