乙醇盐水双水相体系快速测定含酒饮料的酒精度
Quick determination of the content of alcohol in alcoholic beverages by ethanol-salt-water system
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摘要: 考察了7种常见的无机盐对乙醇-水溶液产生相分离的影响,实验结果表明,K2HPO4分相能力最强。通过研究常压、25℃条件下乙醇-K2HPO4-水体系的相图得知,任意体积分数的乙醇-水溶液均可在加入适量的K2HPO4后形成双水相。因此,可在酒类饮料中加入K2HPO4使其形成双水相后,通过测量上相体积来分析饮料中的酒精含量。葡萄酒中的色素、单宁对测定有影响,可以通过加入ADS-8吸附树脂和铬皮粉消除。应用本方法成功测定了白酒、葡萄酒、白兰地酒的酒精度,方法简单、快捷,样品测定标准偏差小于3.0%,回收率为99.2%~101.6%,可以满足酒类饮料酒精度标称含量偏差小于±1.0度的分析要求。Abstract: 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.