Portable Device for Measuring Breath Acetone Based on Sample Preconcentration and Cavity Enhanced Spectroscopy

A portable and compact device is demonstrated for measuring acetone in breath samples. The device features a 7 cm long high finesse optical cavity as an optical sensor that is coupled to a miniature adsorption preconcentrator containing 0.5 g of polymer material. Acetone is trapped out of breath and released into the optical cavity where it is probed by a near-infrared diode laser operating at ∼1670 nm. With an optical cavity mirror reflectivity of 99.994%, a limit of detection of 159 ppbv (1σ) is demonstrated on samples from breath bags. Initial results on direct breath sampling are presented with a precision of 100 ppbv. The method is validated with measurements made using an ion–molecule reaction mass spectrometer. Data are presented on elevated breath acetone from two individuals following an overnight fast and exercise, and from a third individual during several days of routine behavior.