超声提取-GC/MS法测定烟叶中的烷烃

Determination of Alkanes in Tobacco with Ultrasonic Extraction-GC/MS

为研究烟叶中烷烃的分布与含量,分别采用索氏提取、超声辅助提取、同时蒸馏和水蒸气蒸馏4种方法提取烟叶中的烷烃,提取物经浓缩和Si固相萃取柱(500 mg)分离后,进行气相色谱/质谱(GC/MS)分析。在比较提取时间与烷烃提取总量关系的基础上最终选择超声辅助提取。通过对提取溶剂、超声功率、超声时间、料液比、提取次数进行单因素实验及正交实验确定最佳提取条件。结果表明:①最佳提取条件为:提取溶剂二氯甲烷,提取功率560 W、时间15 min,料液比为1∶10,提取次数4次;提取次数是影响烷烃提取量的主要因素。②GC/MS定性出41种烷烃,其中C25～C33之间的烷烃含量占烷烃总量的99%。该方法简便、快速、灵敏,重现性好,适用于烟叶中烷烃的分析。

In order to investigate the distribution and content of alkanes in tobacco, the alkanes in tobacco were extracted respectively by Soxhlet extraction, ultrasonic extraction, simultaneous distillation extraction and steam distillation extraction. The extracts were concentrated and then purified by SPE-Si prior to GC/MS analysis. Ultrasonic extraction was finally chosen for the further study by balancing extraction time and the extraction yield of alkanes. The extraction parameters were optimized by single factor experiments and orthogonal experiment. The results showed that： 1） The optimal parameters were： dichloromethane as solvent, ultrasonic power 560 W, extraction time 15 minutes, sample/solvent ratio 1：10, and repeated extraction for four times. The number of extraction repetition was the key factor affecting extraction yield. 2） Forty-one kinds of alkanes were identified by GC/MS analysis, among them, n-, i-, ai-alkanes between C25-C33 accounted for 99% of the total alkanes. This method is simple, fast and sensitive, features good reproducibility, and is suitable for the determination of alkanes in tobacco leaves.