Thermal desorption from zeolite layer for VOC detection

Abstract

Volatile organic compounds (VOCs) are being considered for a wide range of applications, since they provide information on specific processes (e.g., metabolic processes in humans and plants). To date, environmental VOCs detection can be accomplished with low selectivity using both portable photoionization techniques or using gold standard laboratory techniques (e.g., gas and liquid chromatography, mass spectrometry), getting higher performances and limitations in terms of portability, availability of equipment and of consumption of time. Hereafter, a modified photoionization technique based on a thin zeolite layer for the selective adsorption of VOCs was investigated, exploiting the processes of thermal adsorption and desorption. Zeolite through the inherent nanoporous structure possesses specific electrical characteristics, strongly influenced by the adsorption of the molecules within the framework. Experimental analysis of its electrical and adsorption/desorption properties of propionic and succinic acids was performed. Results demonstrated how the use of a thin nanoporous layer allows to increase the selectivity of commercial photoionization detector during VOC detection, evidencing the potentiality of this technique for the development of low-cost and high-performance sensors in various applications.