Problems involved in the determination of endogenous acetaldehyde in human blood

Little is known about the possible existence of endogenous acetaldehyde in human blood. This has partly been due to analytical difficulties preventing accurate determination of blood acetaldehyde levels with and without the presence of ethanol. In the present study the possible existence of endogenous acetaldehyde in human blood was investigated with headspace gas chromatography using three different procedures for the treatment of samples: (1) no treatment of whole blood, cells, or plasma (direct headspace method), (2) hemolysation, and (3) perchloric acid (PCA) precipitation, prior to the headspace determinations. In in vitro experiments, with the direct headspace and the hemolysation methods, higher acetaldehyde peaks were obtained depending on the headspace incubation time, temperature and ethanol concentration. Both methods displayed about the same values of acetaldehyde in blood cells, ranging between 0 and 40 microM, at incubation times between 15 and 180 min, an incubation temperature of 65 degrees C, and ethanol concentrations less than 5 microM. Less acetaldehyde formation (0-15 microM) was obtained with PCA precipitates of whole blood and cell components. Very low acetaldehyde levels (0-1 microM) were obtained in the supernatants without precipitates from either whole blood or cells after headspace equilibration. Substantially less acetaldehyde was formed in plasma preparations than with whole blood and cell fractions. In human experiments, the disturbance of endogenous or exogenous ethanol was minimized by separating and washing the blood cells followed by PCA treatment. No differences in acetaldehyde concentrations were observed in blood samples taken before, during, or after ethanol intoxication (1.5 g/kg dose) of four healthy non-alcoholic volunteers.(ABSTRACT TRUNCATED AT 250 WORDS)