毛细管气相色谱法测定卷烟中的游离氨基酸

Determination of Free Amino Acids in Tobacco by Ethyl ChloroformateDerivatization and Capillary Gas Chromatography

本试验描述了一种用于烟草中游离氨基酸测定的毛细管气相色谱方法，这种方法基于氯甲酸乙酯衍生化。１ｇ烟样用７５％乙醇经超声波振荡提取后，游离氨基酸用阳离子交换树脂纯化，然后在水溶液中用氯甲酸乙酯（ＥＣＦ）衍生化。该方法简单、衍生化可在水溶液中进行且速度快（常温下仅需５秒）、衍生物较稳定、重现性和回收率实验结果均令人满意。用该法对加料前后的烟草和卷烟中的游离氨基酸进行了分析，结果发现，加料后游离氨基酸尤其是脯氨酸含量呈减少趋势。２３个品牌的国内外卷烟分析表明，云南产的卷烟中游离氨基酸平均含量最高，国外卷烟略低，安徽、上海等华东地区生产的卷烟含量最低。其中云南卷烟所含脯氨酸比其它卷烟要高得多，而国外卷烟的天冬氨酸、天冬酰氨含量较高。

A method of using capillary gas chromatography for the determination of free amino acids in tobacco based on ethyl chloroformate(ECF)derivatization is presented.1.0g of tobacco powder (added with norleucine as internal standard)was used for extraction with 20mL 75% ethanol and sonication.Cleanup of amino acids was accomplished by absorption on a small cationic ionexchange chromatographic column and eluted by water and 4mol/L aqueous ammonia.The amino acids fraction was dried through evaporation under reduced pressure and dissolved into 3mL of 0.1mol/L HCl.Derivatization of amino acids was accomplished with ECF within 5 seconds in aqueous solution. Result show that the method is simple, rapid, sensitive and repeatable in the determination of free amino acids in tobacco. Analysis of uncased and cased tobaccos showed that free amino acids tend to decrease in cased tobaccos,especially for prolin.Analysis of 23 brand cigarettes showed that the total amount of amino acids in Yunnan cigarettes is the highest and that of imported cigarettes is slightly lower while that of Anhui, Shandong and Shanghai cigarettes was the lowest.The content of prolin in Yunan cigarettes is much higher than that of others.While the contents of aspartic acid and asparagine in imported cigarettes were higher than that of domestically made cigarettes.