Design and development of an electronic interface for gas detection and exhaled breath analysis in liquids

Among gas sensors, the ones measuring carbon dioxide and oxygen are crucial for many application fields: the monitoring of air quality, the control of food packaging processes, the study of biochemical mechanisms, and specific reactions related to many different studies in the biomedical context. Many of the sensors used for the measure of carbon dioxide (CO2) and oxygen (O2) are based on electrochemical, optical, and conductometric working principles, which allow to cover the very different ranges of concentration which represent the target of each different field or specific application with good reproducibility and sensitivity. This paper presents a voltammetric sensor showing an innovative approach for the measure of gas and vapors by the interaction of a screen-printed electrode system with the liquid solution, where the gases are conveyed. The design and realization of this sensor system are reported. Calibration tests with CO2 and O2 have given acceptable reproducibility and sensitivity. Besides, this paper shows that new results have been obtained by analyzing exhaled breath collected by control individuals.