Assessment of an automated enzymatic method for ethanol determination in microsamples of saliva

An automated enzymatic (ADH) method is described for ethanol determination in saliva. A 10 microliter sample volume is sufficient for analysis and by means of a Technicon Auto-Analyzer, sixty samples per hour may be run. It has been shown that ethanol is stable in saliva for at least 21 days when the samples are stored in a refrigerator at +4 degrees C, chemical preservatives were not required. The standard deviation of a single determination increased with increase in ethanol concentration in the sample. At a mean saliva ethanol concentration of 11.96 mmol/l, the standard deviation was +/- 0.169 mmol/l, corresponding to a coefficient of variation of 1.4%, implying a high precision. The recovery of alcohol added to saliva was 100.1% of the attributed concentration. Aliquots of the same saliva specimens were analysed using the enzymatic method (y) and by a head-space technique (x) for comparison. The regression equation was y = -0.067 + 1.002x (r = 0.993) inferring no systematic differences. The ADH method introduced has been used to determine the saliva ethanol concentration time course in man after alcohol ingestion.