Monitoring Lipolysis by Sensing Breath Acetone down to ppb

Abstract

Mobile health technologies can provide routinely and on‐demand information to manage metabolic diseases (e.g., diabetes, obesity) and optimize their treatment (e.g., exercise or dieting). Most promising is breath acetone monitoring to track lipolysis and complement standard glucose monitoring. Yet, accurate quantification of acetone down to parts‐per‐billion (ppb) is difficult with compact and mobile devices in the presence of interferants at comparable or higher concentrations. Here, a low‐cost detector that quantifies end‐tidal acetone during exercise and rest (challenging since fine alterations need to be resolved) is presented with excellent bias (25 ppb) and unprecedented precision (169 ppb) in 146 breath samples. It combines a flame‐made Pt/Al2O3 catalyst with a chemoresistive Si/WO3 sensor. The detector is robust against order of magnitude higher ethanol concentrations from disinfection and exercise‐driven endogenous breath isoprene ones, as validated by mass spectrometry. This detector accurately tracked the individual lipolysis dynamics in all volunteers, as confirmed by blood ketone measurements. It can be integrated readily into handheld devices for personalized metabolic assessment at home, in gyms and clinics.