Chitosan-Based Quartz Crystal Microbalance for Alcohol Sensing

Abstract

Short-chain alcohols are a group of volatile organic compounds (VOCs) that are often found in workplaces and laboratories, as well as medical, pharmaceutical, and food industries. Real-time monitoring of alcohol vapors is essential because exposure to alcohol vapors with concentrations of 0.15–0.30 mg·L−1 may be harmful to human health. This study aims to improve the detection capabilities of quartz crystal microbalance (QCM)-based sensors for the analysis of alcohol vapors. The active layer of chitosan was immobilized onto the QCM substrate through a self-assembled monolayer of L-cysteine using glutaraldehyde as a cross-linking agent. Before alcohol analysis, the QCM sensing chip was exposed to humidity because water vapor significantly interferes with QCM gas sensing. The prepared QCM sensor chip was tested for the detection of four different alcohols: n-propanol, ethanol, isoamyl alcohol, and n-amyl alcohol. For comparison, a non-alcohol of acetone was also tested. The prepared QCM sensing chip is selective to alcohols because of hydrogen bond formation between the hydroxyl groups of chitosan and the analyte. The highest response was achieved when the QCM sensing chip was exposed to n-amyl alcohol vapor, with a sensitivity of about 4.4 Hz·mg−1·L. Generally, the sensitivity of the QCM sensing chip is dependent on the molecular weight of alcohol. Moreover, the developed QCM sensing chips are stable after 10 days of repeated measurements, with a rapid response time of only 26 s. The QCM sensing chip provides an alternative method to established analytical methods such as gas chromatography for the detection of short-chain alcohol vapors.

Quartz crystal microbalance coated with PEDOT–PSS/PVA nanofiber for a high-performance humidity sensor

“…Other works also noted that the sensitivity of the QCM humidity sensor was proportional to the loading mass of its active layer (Wang et al, 2010). However, this result is different from ours, as the highest sensitivity was exhibited by the QCM NF 2, which has medium loading mass.…”

Polyvinyl Acetate Film-Based Quartz Crystal Microbalance for the Detection of Benzene, Toluene, and Xylene Vapors in Air

“…The film mass deposited on the QCM surface was calculated using the Sauerbrey equation [14] and was found to be 20.4 µ g. Figure 4a shows the frequency shift of the QCM exposed to the BTX vapors at a concentration of 622 ppm. Soon after analyte injection into the chamber, the QCM resonant frequency decreased For investigation of the sensing performance of the proposed system, we used the static batch system as reported in the previous works [20,21]. The concentration of the injected analyte in the chamber is expressed in ppm and calculated using the equation available in the previous works [22,23].…”

“…The chemical structures of the compounds used in this study are shown in Figure 1. For investigation of the sensing performance of the proposed system, we used the static batch system as reported in the previous works [20,21]. The concentration of the injected analyte in the chamber is expressed in ppm and calculated using the equation available in the previous works [22,23].…”

An Enhanced Safrole Sensing Performance of a Polyacrylonitrile Nanofiber- Based-QCM Sensor by Overlaying with Chitosan

“…The schematic diagram for safrole vapor analysis by the batch system is available in our previous work (Rianjanu et al 2018a;Triyana et al 2018). The QCM sensor was installed in the testing chamber with a volume of 1.25 L.…”

“…Chitosan (Cs) is a natural polymer which consists of a polysaccharide containing the functional groups −OH and −NH 2 and possesses many promising properties such as excellent filmforming ability, high mechanical strength, biodegradability, biocompatibility and antibacterial properties (Ayad et al 2014). Considerable efforts have been devoted to devising gas/vapor sensors using chitosan and its composites as active layers (Ayad & Minisy 2016;Triyana et al 2018;Zhang et al 2017). However, to the best of our knowledge, there has been no effort to develop a promising strategy to modify PAN nanofibers with chitosan and combine these with QCM to construct sensitive safrole sensors.…”