正交试验优选白花蛇舌草超临界二氧化碳萃取条件及GC-MS分析

Optimization of Supercritical Carbon Dioxide Extraction Conditions for Hedyotis diffusa by Orthogonal Test and GC-MS Analysis

目的:优化超临界流体(SFE)萃取白花蛇舌草挥发油工艺参数,并对萃取产物的化学成分进行GC-MS分析。方法:采用正交试验法,以出油率为衡量指标,考察超临界CO2萃取的影响因素(萃取压力、萃取温度、药材粒度),确定其较佳工艺水平,用GC-MS对萃取产物进行分离分析,应用图谱库检索结合KI指数确定各化合物结构,用色谱峰面积归一化法确定萃取产物中各成分的相对百分含量。结果:白花蛇舌草超临界萃取出油率的最佳工艺条件为压力25 MPa、温度50℃,药材粒度20～40目。萃取产物GC-MS结果显示,白花蛇舌草中除含高级脂肪酸及其酯类外,还含有大量的甾族化合物。结论:超临界流体萃取白花蛇舌草挥发油是稳定和可行的;利用GC-MS分析技术结合保留指数鉴定结构的方法准确、快速。

Objective：To optimize the technology parameters of the oil from Hedyotis diffusa by SFE-CO2, and to analyze the extractive components by GC-MS. Method： The experiments were designed with the method of orthogonal experiment, and efficiency of essential oil was used as value standards. The effect of various parameters, i.e., pressure, temperature and sample particle size on yield was investigated with an analytical-scale supercritical fluid extraction （SFE） system to find the optimal conditions. The extractive components were analyzed by GC-MS. The relative content in the essential oil was determined by area normalization. Result： The optimized conditions were as follows： pressure （25 MPa）, temperature （50 ℃） and a sample particle size of 20-40 mesh. The result of the extractive components showed that in addition to containing higher fatty acid and its esters, the oil from H. diffusa also contained a lot of steroidal compounds. Conclusion： The oil from H. diffusa by SFE-CO2 is steady and feasible. It is an accurate and rapid method to identify structure by using GC-MS combined with Kovats retention index.