State Engineering Laboratory for Bio-Resource Eco-Utilization, PR China.
Analyst. 2013 Aug 21;138(16):4631-41. doi: 10.1039/c3an36534d. Epub 2013 Jun 13.
A novel negative pressure and microwave assisted extraction technique (NMAE) was first proposed and applied for extraction of phenolic compounds from pyrola. [C₄MIM]BF₄ aqueous solution was selected as extraction solvent. Optimal extraction conditions were microwave power 700 W, negative pressure -0.07 MPa, temperature 40 °C, liquid-solid ratio 20 : 1, ionic liquid (IL) concentration 0.5 M, extraction time 15 min. The predominance of NMAE was investigated by comparing with microwave-assisted extraction (MAE) and negative pressure cavitation extraction (NPCE) using a first-order kinetics equation. The C∞ values of the target compounds by NMAE were from 0.406 to 5.977 mg g⁻¹ higher than these by MAE and NPCE, which indicated that NMAE had higher extraction yields. The K values of NMAE were also the highest; it was testified that the target compounds could be transferred from matrix into solvent much more effectively by NMAE than by MAE and NPCE. In addition, the NMAE method was validated in terms of repeatability and reproducibility, the relative standard deviation for relative recovery was lower than 5.43 and 8.78%, respectively. Therefore, NMAE was a developed extraction technique for analytical sample preparation. The RP-HPLC-UV method was also successfully applied for the quantification of six target compounds in pyrola.
一种新型的负压微波辅助提取技术（NMAE）首次被提出并应用于从鹿蹄草中提取酚类化合物。[C4MIM]BF4 水溶液被选为提取溶剂。优化的提取条件为微波功率 700 W、负压-0.07 MPa、温度 40°C、液固比 20:1、离子液体（IL）浓度 0.5 M、提取时间 15 min。通过一阶动力学方程比较微波辅助提取（MAE）和负压空化提取（NPCE），研究了 NMAE 的优势。NMAE 中目标化合物的 C∞值比 MAE 和 NPCE 高 0.406-5.977 mg g⁻¹，表明 NMAE 具有更高的提取收率。NMAE 的 K 值也是最高的；这表明与 MAE 和 NPCE 相比，目标化合物可以通过 NMAE 更有效地从基质转移到溶剂中。此外，还对 NMAE 方法的重复性和重现性进行了验证，相对回收率的相对标准偏差分别低于 5.43%和 8.78%。因此，NMAE 是一种用于分析样品制备的开发提取技术。RP-HPLC-UV 法也成功地应用于鹿蹄草中六种目标化合物的定量分析。
