Novel prototype for sampling of alveolar air

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. Acknowledgement: The authors would like to thank Portuguese Foundation for Science and Technology for grant PEst-OE/FIS/UI0068/2011 to CEFITEC