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实验以含醇饮料中所含的乙醇为萃取剂,通过乙醇-K2HPO4-H2O双水相体系萃取结合气相色谱-质谱法,建立了一种检测含醇饮料中氨基甲酸乙酯的方法。考察了双水相体系的形成条件,探讨了双水相体系对氨基甲酸乙酯的萃取效率。实验结果表明:乙醇-K2HPO4-H2O双水相体系对氨基甲酸乙酯具有较高的萃取效率。含醇饮料中加入无机盐形成双水相时,饮料中的糖、蛋白质、单宁等大量极性杂质保留在双水相下相,氨基甲酸乙酯进入双水相上相。由于上相萃取液乙醇极性较强,因此上相中的杂质含量较低,萃取液净化步骤大大简化。在上相萃取液中加入无水MgSO4、PSA(primary secondary amine)去除水分与杂质后直接进样进行GC-MS检测。本文以氨基甲酸叔丁酯为内标准物质,用内标准曲线法定量检测了白酒、白兰地酒、杜松子酒、葡萄酒与黄酒中的氨基甲酸乙酯含量。方法回收率为91.6%~113.9%,RSD为0.70%~5.9%,检出限为1.3μg/L。
In the experiment, ethanol contained in alcoholic beverages was used as extractant to establish a method for the determination of urethane in alcoholic beverages by ethanol-K2HPO4-H2O aqueous two-phase extraction combined with gas chromatography-mass spectrometry. The formation conditions of aqueous two-phase system were investigated. The extraction efficiency of urethane in aqueous two-phase system was also discussed. The experimental results show that ethanol-K2HPO4-H2O aqueous two-phase system has higher extraction efficiency for urethane. When alcohol is added into the alcoholic beverage to form a double aqueous phase, a large amount of polar impurities such as sugar, protein and tannin in the beverage are retained in the lower aqueous phase and the urethane enters the upper aqueous phase. Due to the higher phase polarity of the ethanol extract, the impurity content in the upper phase is lower and the extract purification step is greatly simplified. In the phase extract was added anhydrous MgSO4, PSA (primary secondary amine) to remove water and impurities directly injected for GC-MS detection. In this paper, tert-butyl carbamate as an internal standard substance, with the standard curve method for the quantitative determination of white wine, brandy, gin, wine and rice wine in the urethane content. The method recoveries ranged from 91.6% to 113.9% with RSDs of 0.70% to 5.9% with a detection limit of 1.3 μg / L.