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目的优化逆三相膜萃取烟叶中烟碱的提取工艺。方法采用聚四氟乙烯膜(PTFE)作为萃取膜,硫酸溶液作为酸相、氢氧化钠溶液作为碱相、氯仿作为有机相的逆三相膜萃取循环系统萃取烟碱叶中烟碱。依据烟碱在261 nm处有特征吸收,采用紫外分光光度计检测烟碱叶中游离烟碱的含量。以烟碱萃取率为指标,考察酸浓度、碱浓度、循环时间、酸碱水相及有机相体积比和流速5个因素,选定最佳工艺。结果提取烟叶中烟碱的最佳提取工艺条件为:酸浓度0.01%,碱浓度5%,循环时间25 min,体积比(酸碱相∶有机相)2.5∶1,流速6 m L/min,烟碱的提取率达到99.07%。对正交试验数据进行统计分析,差异有统计学意义(P<0.05)。按最佳工艺进行3次重复实验,结果显示烟碱提取率均值达到99.01%。结论该工艺操作简单,萃取时间快,有机溶剂的消耗量少,易实现工业化,环境污染少,适用于烟叶中烟碱的提取。
OBJECTIVE To optimize the extraction process of nicotine in tobacco by reverse three-phase membrane extraction. Methods Extraction of nicotine from Nicotiana tabacum was carried out using polytetrafluoroethylene (PTFE) membrane as extraction membrane, sulfuric acid solution as acid phase, sodium hydroxide solution as base phase and chloroform as the reverse phase three phase membrane extraction and recovery system of organic phase. Based on the absorption of nicotine at 261 nm, the content of free nicotine in nicotine leaves was detected by UV spectrophotometer. Taking nicotine extraction rate as an index, 5 factors including acid concentration, alkali concentration, circulation time, acid-base water phase, volume ratio of organic phase and flow rate were investigated. Results The optimum extraction conditions of nicotine in tobacco leaves were as follows: acid concentration 0.01%, alkali concentration 5%, circulation time 25 min, volume ratio (pH = 2.5: 1), flow rate 6 mL / min, Nicotine extraction rate of 99.07%. Statistical analysis of the orthogonal test data, the difference was statistically significant (P <0.05). According to the best three times of repeated experiments, the results showed that the average nicotine extraction rate reached 99.01%. Conclusion The process is simple, fast extraction time, less consumption of organic solvents, easy to industrialization, less environmental pollution, suitable for tobacco nicotine extraction.