乙醇-K_2HPO_4-H_2O双水相体系萃取-气相色谱质谱联用检测含醇饮料中的氨基甲酸乙酯

Determination of ethyl carbamate in alcoholic beverages using ethanol-K_2HPO_4-H_2O aqueous two-phase extraction combined with gas chromatography/mass spectrometry

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 this paper ethanol in alcoholic beverages was used as an extraction solvent. Based on the ethanol - K2HPO4-H2O aquatic two phase system （ATPS） coupled with GC/MS, an effective sample pretreatment method was developed for the analysis of ethyl carbamate. The influence factors on formation of ethanol-salt-H2O system were discussed in depth. Meanwhile, the influence of the ethanol- K2HPO4-H2O aquatic two phase system on extraction of ethyl carbamate in alcoholic beverages was detailedly investigated. The results showed that ethyl carbamate was extracted into upper phase with high efficiency. When K2HPO4 was added in alcoholic beverage to form aqueous two phase system, the most of polarity chemical impurities such as sugar, protein, tannin and pigment were distributed in lower phase, and ethyl carbamate was extracted in up phase. Because of the higher chemical polarity of ethanol, the lipid-soluble impurities are extracted less in up phase of ATPS. Therefore the purification steps were greatly simplified. The anhydrous magnesium sulfate （MgSO4） and primary secondary amine （PSA） were added in upper phase to eliminate the moisture and other impurities. Then, the ethyl carbamate in extract （upper phase） was directly analyzed by GC/MS with the internal standard method （tert- butyl c^rbamate as an internal standard）. This proposed approach was satisfactorily applied to the determination of ethyl carbamate in white spirit, brandy, geneva, grape and rice wine. The recoveries were 91.6% - 113.9%, with relative standard deviations of 0. 70% -5.9%, and the detection limit was 1.3 μg/L.