Ionic Liquid-Based Quartz Crystal Microbalance Sensors for Organic Vapors: A Tutorial Review

Abstract

Organic vapor sensors are used in diverse applications ranging from environmental monitoring to biomedical diagnostics. Among a number of these sensors, quartz crystal microbalance (QCM) sensors prepared by coating ionic liquids (ILs) or their composites are promising devices for the analysis of volatile organic compounds (VOCs) in complex chemical mixtures. Ionic liquids are remarkable materials, which exhibit tunable physico-chemical properties, chemical and thermal stability, multiple interactions with diverse group of molecules, and enormous structural variability. Moreover, ILs exhibit viscoelastic properties, and hence these materials are ideal for creation of QCM virtual sensor arrays. While the scientific literature on IL-coated QCM sensors is rapidly growing, there is still much to learn. This manuscript provides a comprehensive review on the development of IL-coated QCM sensors and multi-sensor arrays as well as their applications for the analysis of VOCs in complex mixtures. Furthermore, IL-coated QCM virtual sensor arrays and their applications are presented. A short overview of some of the QCM designs, future research areas, and recommendations are also discussed. This short review is a necessary first step towards standardization and further development of QCM for the analysis of VOCs.

On-Site Detection of Volatile Organic Compounds (VOCs)

“…Due to their viscoelastic nature ionic liquids have gained much interest as a coating for QCMs in recent years [ 60 , 61 ].…”

Overtone Mass Sensitivity of Quartz Crystal Microbalance Sensor with Asymmetric N-M Type Electrode Configuration

“…The quartz crystal microbalance (QCM) is a kind of sensor based on the piezoelectricity of a quartz crystal to detect a nanogram mass change and the thickness of a nano thin film. − The core part of a QCM sensor is the quartz resonator, which consists of a thin quartz wafer with two metal electrodes . Over the last several decades, the QCM sensor has been used widely in gas phase − and liquid phase − research due to its superior performance. It is highly sensitive and has a low cost and real-time detection .…”