Evaluation of ethanol analysis on brain and liver by head-space gas chromatography

An evaluation of the reliability of ethanol analysis in brain by the head-space gas chromatographic method has shown the following. (a) This method may be used directly, without prior distillation, with homogenized brain tissue; (b) a good correlation exists with values obtained on blood (blood/brain ratio of 0.97 and 1.32 for blood ethanol concentrations of 0.1 and 0.2 g/dl respectively); (c) in non-preserved blood, there is a 15% deviance in the correlation resulting from changes in ethanol concentration; (d) the same evaluation applied to ethanol analysis in liver reveals a poor correlation between the results in liver and blood; this is believed to result mainly from natural oxidative losses of ethanol in liver, and also from the variable fat content of the liver samples analyzed. Caution is emphasized with regard to interpretations of blood/brain and blood/liver ethanol concentration ratios for the purpose of determining pre- and post absorption stages of intoxication where samples involved are not properly preserved.