Acetaldehyde from breath

One example of autooxidation you have experienced is the room-temperature oxidation of alcohol in wine. Within days and sometimes within minutes of opening a bottle of wine, the taste begins to deteriorate because of autooxidation. This converts the ethanol into acetaldehyde and to acetic acid, both of which taste bad. Wine lovers talk about letting the wine breathe after opening so apparently some oxidation actually helps the taste. Distilled vinegar is made by the intentional oxidation of the alcohol in fermented apple juice into acetic acid, which can then be distilled from the juice and pulp. 

Jones et al. (1985) estimated the concentration of acetaldehyde in blood from analysis in breath. The method is based on liquid-air partition coefficients of acetaldehyde determined by GC-FID. Jones et al. (1986) reported a GC-headspace method for its analysis in wine. Habboush et al. (1988) have reported the analysis of acetaldehyde and other low-molecular-weight aldehydes in automobile exhaust gases by GC-FlD. 

Jones, A. W., A. Sato, and O. A. Forsander. 1985. Liquid/air partition coefficients of acetaldehyde values and limitations in estimating blood concentrations from analysis in breath. Alcohol Clin. Exp. Res. 9(5) 461-64 cited in Chem. Abstr. CA 104(3) 17224q. 

---