Gas-liquid chromatographic analysis of ethanol and acetaldehyde in blood with minimal artifactual acetaldehyde formation.

A gas-liquid chromatographic procedure utilizing headspace gas analysis is described for the determination of ethanol and its metabolite, acetaldehyde, in a 100-microliters sample of blood from the rat, guinea pig, sheep, or human. Artifactual formation of ethanol-derived acetaldehyde is minimized during sample preparation by using a chemical solution containing perchloric acid and sodium azide in saline, and thiourea. Aqueous standards of ethanol and acetaldehyde are used to calibrate the procedure, and 1-propanol is used as the internal standard of the method. The recovery of ethanol and acetaldehyde from spiked blood samples is quantitative and reproducible, with a within-day coefficient of variation of less than 7% for ethanol and less than 9% for acetaldehyde. The lower limit of quantitative sensitivity is 0.006 mg/ml ethanol and 0.10 microgram/ml acetaldehyde. The instrumental analysis time is less than 3 min, which enables high sample throughput.