Abstract: A compact, portable or handheld device for measurement of breath VOCs such as acetone is described, which incorporates a flow measurement sensor, a mini preconcentrator unit and an spectroscopy unit, such as a cavity-enhanced absorption spectrometer. The preconcentrator includes a chemically selective material to trap VOCs, which is supported on a metal foam. The apparatus is suitable for measuring sub ppm levels of breath VOCs such as acetone and for tracking blood ketone levels.

Abstract: A device for measuring oxygen uptake and carbon dioxide production by a respiring subject based on the use of absorption spectroscopy. An absorption spectrometer using cavity enhanced absorption spectroscopy at 763 nm to measure oxygen concentration and direct absorption or wavelength modulation spectroscopy at 2.0035 ?m for carbon dioxide concentration is incorporated into a breathing tube in proximity to the respiring subject. This provides measurements of oxygen and carbon dioxide concentration with a good temporal resolution which can be combined with measurements of flow rate as a function of time to obtain oxygen uptake and carbon dioxide production on a breath-by-breath basis. The device can also measure the concentration of water vapor and of anaesthetic gases in exhaled breath.

Abstract: A device for measuring oxygen uptake and carbon dioxide production by a respiring subject based on the use of absorption spectroscopy. An absorption spectrometer using cavity enhanced absorption spectroscopy at 763 nm to measure oxygen concentration and direct absorption or wavelength modulation spectroscopy at 2.0035 ?m for carbon dioxide concentration is incorporated into a breathing tube in proximity to the respiring subject. This provides measurements of oxygen and carbon dioxide concentration with a good temporal resolution which can be combined with measurements of flow rate as a function of time to obtain oxygen uptake and carbon dioxide production on a breath-by-breath basis. The device can also measure the concentration of water vapour and of anaesthetic gases in exhaled breath.

Abstract: Methods and apparatus for the analysis of exhaled breath by spectroscopy are disclosed. An optical cavity containing the exhaled breath, typically comprising a pair of opposing high reflectivity mirror, is used to implement a cavity enhanced absorption technique. Pairs of 12CO2 and 13CO2 absorption lines suitable for use in spectroscopic breath analysis are also disclosed.

Abstract: Methods and apparatus for the analysis of exhaled breath by spectroscopy are disclosed. An optical cavity containing the exhaled breath, typically comprising a pair of opposing high reflectivity mirrors, is used to implement a cavity enhanced absorbtion technique. Pairs of 12CO2 and 13CO2 absorbtion lines suitable for use in spectroscopic breath analysis are also disclosed.

Abstract: Methods and apparatus for the analysis of exhaled breath by spectroscopy are disclosed. An optical cavity containing the exhaled breath, typically comprising a pair of opposing high reflectivity mirrors, is used to implement a cavity enhanced absorbtion technique. Pairs of 12CO2 and 13CO2 absorbtion lines suitable for use in spectroscopic breath analysis are also disclosed.