Xiang Lei-Wen, Liu Yan, Li Hai-Fang, Lin Jin-Ming
Beijing Key Laboratory of Microanalysis Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing, PR China.
Institute of Food and Fermentation Industries, Fuqing Branch of Fujian Normal University, Fuqing, PR China.
J Sep Sci. 2016 Jul;39(13):2466-73. doi: 10.1002/jssc.201600247. Epub 2016 Jun 21.
Acid hydrolysis and alkaline saponification were incorporated into a microwave-assisted extraction process for the simultaneous extraction of free and conjugated phytosterols from tobacco. The crude extract of the microwave-assisted extraction was purified by C18 solid-phase extraction and then determined by high-performance liquid chromatography. Phytosterols of cholesterol, ergosterol, stigmasterol, campesterol, and β-sitosterol were determined by chromatographic quantification. The multiple parameters of microwave-assisted extraction were optimized by a uniform design method. The optimal ratio of extraction ethanol solvent to tobacco mass was 30 mL/g. The microwave-assisted extraction acid hydrolysis was carried out in sulfuric acid medium by heating for 10 min at 55°C. The microwave-assisted extraction alkaline saponification was performed after adding excessive sodium hydroxide by heating another 10 min. The repeatability of the proposed method was acceptable with recoveries from 69.68 to 88.17% for the phytosterols. Five target phytosterols were all found in the tobacco samples, and the contents were significantly different in samples from different producing areas.
将酸水解和碱皂化纳入微波辅助萃取工艺，用于同时从烟草中萃取游离和共轭植物甾醇。微波辅助萃取的粗提物通过C18固相萃取进行纯化，然后用高效液相色谱法测定。通过色谱定量法测定胆固醇、麦角甾醇、豆甾醇、菜油甾醇和β-谷甾醇等植物甾醇。采用均匀设计法对微波辅助萃取的多个参数进行了优化。萃取乙醇溶剂与烟草质量的最佳比例为30 mL/g。微波辅助萃取酸水解在硫酸介质中于55°C加热10分钟进行。加入过量氢氧化钠后，再加热10分钟进行微波辅助萃取碱皂化。该方法的重复性良好，植物甾醇的回收率在69.68%至88.17%之间。在烟草样品中均发现了5种目标植物甾醇，不同产地样品中的含量存在显著差异。
