Comparison of rat blood preparation methods for acetaldehyde assay

A comparison is made of four previously described methods for the preparation of blood for acetaldehyde (AcH) assay in the rat. The spontaneous formation of AcH which occurs during the treatment of blood containing ethanol and the recovery of known amounts of AcH added to the blood were studied. The methods using sodium nitrite-sulfosalicylic acid or perchloric acid (PCA) in saline gave low levels of spontaneous formation (1 to 2 microM AcH for 48 mM ethanol). In the recovery studies it was seen that semicarbazide does not allow displacement of all the AcH; treatment of the blood with the reactant sodium nitrite-sulfosalycilic acid and use of the hemolysis method gave levels of recovery lower than 50%. Only treatment of the blood with perchloric acid in NaCl allowed all the AcH added to the blood to be recovered. In vivo, PCA in saline releases the AcH which was seen to remain bound in the red blood cells with the semicarbazide method. So the recommended procedure for accurate assay of blood AcH in the rat is cold deproteinization in PCA/saline before head-space gas chromatography. The levels of in vivo blood AcH (4.1 +/- 0.33 microM) obtained in the rat using this method for a blood alcohol concentration of 52 mM are lower than those previously described in the literature.