A new photometric assay for blood alcohol

The proposed method for ethanol determination is based on the simultaneous oxidation of ethanol and reduction of nitrosodimethylaniline to a quinonediimine derivative in the presence of NAD and horse liver alcohol dehydrogenase. Quinonediimine formed in this reaction is coupled with salicylamide and the absorbance of the resulting blue indaniline dye is measured. The new method yields identical results when compared with the currently used methods for the determination of blood alcohol (i.e., with the conventional enzymatic method, Widmark's method, and gas chromatography). Its main advantage is high sensitivity, little consumption of both enzyme and coenzyme, and the measurement in the visible range of the spectrum.