Quick determination of the content of alcohol in alcoholic beverages by ethanol-salt-water system

The effect of seven different inorganic salts on the phase separation in ethanol-water solution had been studied.The results showed that potassium hydrogen phosphate (K2HPO4) was the best salt to form aqueous two-phase system (ATPS) .Any volume fraction of ethanol-water system would be separated into ATPS when suitable amount of K2HPO4 was added into the system, according to the phase diagrams of K2HPO4 in ethanol-water system which was determined at 25℃ and normal atmospheric pressure.So the content of alcohol in alcoholic beverages can be determined by measuring the volume of the up-phase of ATPS which was formed by adding salt in the beverages.ADS-8 resin and hide power were added to eliminate the influence of anthocyanins and tannins on measures.The method had been successfully used to determine the content of alcohol in spirit, wine and brandy.The method was simple and quick.The accuracy of this method was evaluated by measuring the recovery from spiked samples.Total recoveries were 99.2% ～ 101.6% with relative standard deviation values less than 3.0%, which could meet the requirement for analysis in alcoholic beverages with the nominal content ± 1.0 degree.