A coordinated study of the dispersal of water between the various body compartments (stomach and gut, blood stream and tissue) and the similar dispersal kinetics of
ethanol and its metabolism has been carried out involving two healthy volunteers using flowing afterglow mass spectrometry, FA-MS, and selected ion flow tube mass spectrometry, SIFT-MS. Thus, using these techniques, the variations of HDO and
ethanol in breath, measured in successive single exhalations, were followed in real time after the ingestion of measured quantities of D2O and
ethanol in proportion to the
body weights of the subjects at the dose rates D2O approximately 0.283 g kg-1,
ethanol approximately 0.067 g kg-1. During the FA-MS experimental periods (about 2 h), the dispersion of HDO into the body water and finally its equilibration in the total body water is observed from which total body water for each subject was determined. In the SIFT-MS measurements, the dispersion of
ethanol into the body water and its loss via metabolism was observed until the physiological (pre-dose) breath level of
ethanol for each individual was restored. A simple linear transformation is used to derive the time variations of the blood levels of HDO and
ethanol. This has allowed a comparison of the fractions of the ingested
ethanol that are metabolized during first-pass metabolism for the two subjects. Thus, in one subject 30% and in the other subject 40% of the ingested alcohol is metabolized in the first 20 min following ingestion. The good time resolution allowed by non-invasive breath analysis ensures that the rates of processes such as
ethanol metabolism can be accurately measured. Simultaneous measurements of breath
acetaldehyde (largely formed via the
ethanol metabolism) and
acetone were also performed during the SIFT-MS single breath exhalations.