To be able to detect carbon dioxide (CO2) with high accuracy and fast response time is critical for many health and environmental applications. We report on a pocket-sized CO2 sensor for real-time analysis of end-tidal CO2, and environmental CO2. The sensor shows fast and reversible response to CO2 over a wide concentration range, covering the needs of both environmental and health applications. It is also immune to the presence of various interfering gases in ambient or expired air. Furthermore, the sensor has been used for real-time breath analysis, and the results are in good agreement with those from a commercial CO2 detector.
Keywords: breath-by-breath analysis; capnography; carbon dioxide environmental analysis; colorimetric sensor; end-tidal CO2; respiratory diseases.