Design and Analysis of Exhaled Breath Condenser System for Rapid Collection of Breath Condensate

Breath analysis has attracted a lot of interest for noninvasive health diagnostics method by detecting disease biomarkers. However, the exhaled breath collection process remains a challenge. Specifically, the effective separation of the water vapor from the breath sample, which is necessary to avoid humidity interference in gas detection system and to preserve the liquid condensate for other analysis. In this paper, an analytical model is developed to obtain the optimized condenser for portable breath collection system to effectively provide both dry gas phase sample and exhaled breath condensate. The mathematical model is verified by using a heated water bubbler as warm and humid air generator (in vitro). Furthermore, the performance of the device is tested by using actual human breath (in vivo). The in vitro test result shows the temperature and moisture concentration values have a good agreement with the measured values with margin of error ±15%, and ±30% for amount of collected condensate. The in vivo result shows, with the thermoelectric element cooled up to 8.5 °C, a moisture removal efficiency of 62.4% is achieved. In this case, the system can collect exhaled breath condensate of 0.457 ± 0.092 ml and dry gas (RH 47.8% at 27 °C) for 10 exhalations.