Laser-based human breath analysis: D/H isotope ratio increase following heavy water intake

Abstract

Following the ingestion of only 5.1 mL of D2O, a mid-infrared laser spectrometer determines the D/H isotope ratio increase in exhaled water vapor for the first time, to the best of our knowledge. This increase is still detectable several weeks after the heavy water intake. Collected breath samples are directly transferred into a high-temperature multipass cell operated at 373 K. No breath sample preparation is required. Aside from the capability to hinder unwanted condensation, measurements at elevated temperatures offer other advantages such as a lower temperature dependence of the delta value or the possibility to vary the intensity of absorption lines. We lay the foundation for many laser-based clinical applications. As an example, we measure a total body water weight of 55.2%+/-1.8% with respect to the total body weight, in agreement with the normal value of the male population.

Infrared Spectroscopy on Smoke Produced by Cauterization of Animal Tissue

“…It has been used for several studies [16–18] but since some modifications were made it is briefly described here.…”

Laser spectroscopy for breath analysis: towards clinical implementation

“…Another approach is to use external-cavity diode lasers (ECDLs) and external-cavity quantum cascade lasers (EC-QCLs), where the laser is mounted in an optical cavity comprising a wavelength selective device, which provides a narrow linewidth and broadband wavelength tuning range (up to 100 cm −1 ) [36]. Setups based on direct absorption spectroscopy, which can only be used to detect the highly abundant species in breath carbon dioxide (CO 2 ) and water vapor (H 2 O) [35][36][37], usually achieve a Noise Equivalent Absorption Sensitivity (NEAS) of 10 −3 -10 −5 cm −1 Hz −1/2 . The online, real-time measurement and analysis of CO 2 exhalation profiles (capnography) with NDIR spectroscopy is by far the most widely used application of breath analysis in clinical practice.…”

Breath Analysis Using Laser Spectroscopic Techniques: Breath Biomarkers, Spectral Fingerprints, and Detection Limits

“…Measurements of dilutions of D 2 O can be used to determine the total body water (H 2 O) [152]. Recently, Bartlome et al have demonstrated breath analysis of the D/H isotope ratios using a home-built tunable, pulsed DFG laser source operating in the wavelength range of 3.5–3.65 μm (2,740–2,857 cm −1 ) combined with a high temperature multipass gas cell [91]. The minimum detectable absorption coefficient of the system was 2.6 × 10 −6 (3σ).…”