Estimation of blood acetaldehyde during ethanol metabolism: a sensitive HPLC/fluorescence microassay with negligible artifactual interference.

A novel high performance liquid chromatographic (HPLC) procedure has been developed for the quantitation of acetaldehyde in 50 microliter samples of primate whole blood during ethanol metabolism. This microassay has a minimum detectable concentration of about 0.1 microM, displays an intra-assay precision under 10%, and is linear over a reasonable concentration range. Of importance is that negligible acetaldehyde is generated artifactually from ethanol during blood analysis. The assay is based on the reaction of acetaldehyde with 1,3-cyclohexanedione and ammonium ion to form a water-soluble fluorogenic adduct, which is separated by reversed phase HPLC and quantitated fluorometrically. Propionaldehyde, added as an internal standard, forms an analogous separable adduct. Blood acetaldehyde concentrations in Rhesus monkeys were between 1-2 microM 150 min after acute administration of ethanol (1.5 g/kg). Traces of endogenous components which are chromatographically identical with cyclohexanedione adducts of acetaldehyde and formaldehyde also were apparent in blood from monkeys and humans not given ethanol.