Lu Yanbin, Ma Wenyan, Hu Ruilin, Dai Xiaojing, Pan Yuanjiang
Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
J Chromatogr A. 2008 Oct 24;1208(1-2):42-6. doi: 10.1016/j.chroma.2008.08.070. Epub 2008 Aug 23.
An ionic liquid-based microwave-assisted extraction (ILMAE) approach has been successfully applied to the effective extraction of the phenolic alkaloids present in samples of the medicinal plant Nelumbo nucifera Gaertn. The ionic liquids investigated comprised a range of four anions, four 1-alkyl-3-methylimidazolium derivatives differing in hydrophobic chain length. The results indicate that varying the anion has apparent effects on the overall extraction efficiency. In addition, the influence of some microwave parameters, such as irradiation power, extraction time and solid-liquid ratio, are also investigated. Under the optimized conditions, the proposed approach has been evaluated in comparison with the conventional heat-reflux extraction (HRE) and regular MAE. The reduction of the extraction times (from 2h to 90s) and remarkable higher efficiency (20-50% improved) supports the suitability of the proposed approach. In addition, the proposed method is validated by the recovery, correlation coefficient (R(2)), and reproducibility (RSD, n=5), which are in the range of 98-105%, 0.9994-0.9998, and 1.2-5.4%, respectively.
一种基于离子液体的微波辅助萃取（ILMAE）方法已成功应用于有效萃取药用植物莲（Nelumbo nucifera Gaertn.）样本中的酚类生物碱。所研究的离子液体包含一系列四种阴离子、四种疏水性链长不同的1-烷基-3-甲基咪唑鎓衍生物。结果表明，改变阴离子对整体萃取效率有明显影响。此外，还研究了一些微波参数的影响，如辐照功率、萃取时间和固液比。在优化条件下，将所提出的方法与传统热回流萃取（HRE）和常规微波辅助萃取（MAE）进行了比较评估。萃取时间的减少（从2小时降至90秒）以及显著更高效率（提高20 - 50%）证明了所提出方法的适用性。此外，所提出的方法通过回收率、相关系数（R(2)）和重现性（RSD，n = 5）进行了验证，回收率在98 - 105%范围内，相关系数在0.999４ - 0.9998范围内，重现性在1.2 - 5.4%范围内。
