Extraction and Chromatographic Determination of Shikimic Acid in Chinese Conifer Needles with 1-Benzyl-3-methylimidazolium Bromide Ionic Liquid Aqueous Solutions

Abstract

An ionic liquids-based ultrasound-assisted extraction (ILUAE) method was successfully developed for extracting shikimic acid from conifer needles. Eleven 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were investigated and 1-benzyl-3-methylimidazolium bromide solution was selected as the solvent. The conditions for ILUAE, including the ionic liquid concentration, ultrasound power, ultrasound time, and liquid-solid ratio, were optimized. The proposed method had good recovery (99.37%–100.11%) and reproducibility (RSD,n= 6; 3.6%). ILUAE was an efficient, rapid, and simple sample preparation technique that showed high reproducibility. Based on the results, a number of plant species, namely,Picea koraiensis, Picea meyeri, Pinus elliottii,andPinus banksiana,were identified as among the best resources of shikimic acid.