The enzymatic assay of ethanol in beverages is based on the conversion of ethanol to acetaldehyde by alcohol dehydrogenase, using spectrophotometric detection with NAD+ / NADH reaction monitored at 340 nm.
Two approaches were used to monitor the course of reaction : stop flow reaction rate measurement (A) and kinetic, flow through technique whereby the raction mixture moved continuously through the flow cell (B). A linear dynamic application range up to 0.040% (v/v)was achieved for both initial rate and for the kinetic peak height measurement, with good repeatability (R.S.D. < 5.0% and <1.0%, respectively)’
A variety of alcoholic beverages was successfully analyzed, including red and white wine, beers and various spirits.
2.4.3.
