气相色谱法测定低酒精度饮料中乙醇的含量

分别采用静态顶空气相色谱法与传统蒸馏后进样的气相色谱法测定低酒精度饮料中乙醇含量。选用TGWAXMS色谱柱。2种方法在乙醇体积分数为0.01%~5.00%时均具有良好的线性关系。传统蒸馏法乙醇的体积分数检出限为0.003%,静态顶空法检出限为0.001%。试验结果表明传统蒸馏后进样的气相色谱法由于前处理步骤繁琐,导致回收率相对较低(83%~91%)。而静态顶空法直接测定饮料中乙醇的方法具有前处理简单,待测物质乙醇不易损失等优点,回收率为97%~100%。

Determination the content of ethanol in low alcohol beverages by gas chromatography

The ethanol content of beverages was measured by two methods, the static headspace gas chromatography and the traditional method of gas chromatography after distillation, using TG-WAXMS chromatographic column. The two methods had good linear relationship in the volume fraction of ethanol ranging from 0.01% to 5.00%. In traditional distillation method, the detection limit of volume fraction of ethanol was 0.003%, and the detection limit of static headspace was 0.001%. The results showed that due to the complicated pre-treatment processes, the recovery rate of the gas chromatography after traditional distillation was relatively low (83%~91%). While the method of direct determination of ethanol in the beverage by static headspace method was simple, and kept the ethanol stable during the detection. The recovery rate was between 97% and 100%.