Advances in colorimetric and optical sensing for gaseous volatile organic compounds

Abstract

Exposure to volatile organic compounds (VOCs) can exert serious impacts on human health. The detection and identification of VOCs are, therefore, important both in outdoor and indoor (whether workplace or residential) environments. The use of colorimetric and optical sensing techniques for VOCs is expected to offer new ways to overcome many limitations in traditional gas sensing systems. In this work, a classification of colorimetric and optical sensing devices was made and discussed with respect to the sensing mechanisms, principles, and sensing materials for common VOCs (e.g., alcohols, aldehydes, alkenes, aromatic compounds, halogenated VOCs, ketones, and polycyclic aromatic hydrocarbons). The performances of these sensing approaches were also evaluated in terms of sensitivity relative to other available detection methods. Furthermore, this paper offers an extensive review of recent progresses in this area with a discussion on the future challenges associated with the expansion of colorimetric/optical sensing techniques.