Laser-based method and sample handling protocol for measuring breath acetone.
A robust method is demonstrated to measure acetone in human breath at sub parts-per-million by volume (ppmv) concentrations using diode laser cavity enhanced absorption spectroscopy. The laser operates in the near-infrared at about 1690 nm probing overtone transitions in acetone in a spectral region relatively free from interference from common breath species such as CO2, water, and methane. Using an optical cavity with a length of 45 cm, bound by mirrors of 99.997% reflectivity, a limit of detection of ∼180 parts-per-billion by volume (ppbv) (1σ) of breath acetone is achieved. The method is validated with measurements made with an ion-molecule reaction mass spectrometer. A technique to calibrate the optical cavity mirror reflectivity using a temperature dependent water vapor source is also described.
Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford, OX1 3QZ, United Kingdom.
Gus
G
Hancock
Cathryn E
CE
Langley
Robert
R
Peverall
Grant A D
GA
Ritchie
David
D
Taylor
D000096:Acetone / Q000032:analysis*; D001944:Breath Tests; D006801:Humans; D007834:Lasers; D057230:Limit of Detection; D013048:Specimen Handling; D019265:Spectroscopy, Near-Infrared / Q000379:methods
D000096:Acetone