Prototype and Graphical Interface for Selective Exhaled Air Acquisition

The recent advances in technology and detection methods, as well as its economic viability have pointed the analysis of exhaled breath as a promising tool for medical diagnosis or therapy monitoring. Since the concentration of the most Volatile Organic Compounds (VOCs) present in the exhaled breath is very low (ppbv – pptv range) it is important to have a selective sampling system for alveolar air. In this work we present the design and instrumentation of a prototype that allows real time monitoring of the breathing cycle and automatically decide the correct moment for acquisition and channel the acquired sample to the Ion Mobility Spectrometer with Multi-Capillary Column pre-separation (MCC-IMS). The prototype is composed by a flow meter, signal packaging circuits and a flow commuting circuit (three-way valve). Two graphical interfaces were also developed to help controlling the whole process of acquisition making it easy, quick and reliable.