Detection of Volatile Organic Compounds Adsorbed Onto Zeolite Layers

Volatile organic compounds (VOCs) are potential biomarkers for different diseases, such as cancer since they are differently expressed already in the early stage of the disease. The development of a reliable, non-invasive device for the rapid quantification of VOCs is a topic of interest, especially for the non-invasive screening of large populations. Among VOCs, butyric, propionic, and succinic acids are involved in the metabolic processes of several cancers, and thus they are considered promising candidate biomarkers. These would be useful for non-invasive diagnostic strategies, improving disease detection even at early stages. This work is focused on the design and fabrication of a sensor to detect alterations of specific metabolites in human saliva, a rich source of VOCs. The sensor is based on a thin layer of nanoporous material (zeolite), which act as a VOC adsorber. The detection is based on the evaluation of emission profiles by using a photoionization detector. The VOC quantification is evaluated through the analysis of the emission profiles of the molecules adsorbed in the nanoporous layer, which are affected by the morphologic characteristics of the layer and by the environmental temperature and relative humidity. Results are promising for the development of a system for VOC detection and non-invasive diagnosis.