Comparison of the Partition Efficiencies of Multiple Phenolic Compounds Contained in Propolis in Different Modes of Acetonitrile–Water-Based Homogenous Liquid–Liquid Extraction

oleh: Wenbin Chen, Xijuan Tu, Dehui Wu, Zhaosheng Gao, Siyuan Wu, Shaokang Huang

Format: Article
Diterbitkan: MDPI AG 2019-01-01

Deskripsi

Homogeneous liquid&#8315;liquid extraction (HLLE) has attracted considerable interest in the sample preparation of multi-analyte analysis. In this study, HLLEs of multiple phenolic compounds in propolis, a polyphenol-enriched resinous substance collected by honeybees, were performed for improving the understanding of the differences in partition efficiencies in four acetonitrile&#8315;water-based HLLE methods, including salting-out assisted liquid&#8315;liquid extraction (SALLE), sugaring-out assisted liquid&#8315;liquid extraction (SULLE), hydrophobic-solvent assisted liquid&#8315;liquid extraction (HSLLE), and subzero-temperature assisted liquid&#8315;liquid extraction (STLLE). Phenolic compounds were separated in reversed-phase HPLC, and the partition efficiencies in different experimental conditions were evaluated. Results showed that less-polar phenolic compounds (kaempferol and caffeic acid phenethyl ester) were highly efficiently partitioned into the upper acetonitrile (ACN) phase in all four HLLE methods. For more-polar phenolic compounds (caffeic acid, <i>p</i>-coumaric acid, isoferulic acid, dimethoxycinnamic acid, and cinnamic acid), increasing the concentration of ACN in the ACN&#8315;H<sub>2</sub>O mixture could dramatically improve the partition efficiency. Moreover, results indicated that NaCl-based SALLE, HSLLE, and STLLE with ACN concentrations of 50:50 (ACN:H<sub>2</sub>O, <i>v</i>/<i>v</i>) could be used for the selective extraction of low-polarity phenolic compounds. MgSO<sub>4</sub>-based SALLE in the 50:50 ACN&#8315;H<sub>2</sub>O mixture (ACN:H<sub>2</sub>O, <i>v</i>/<i>v</i>) and the NaCl-based SALLE, SULLE, and STLLE with ACN concentrations of 70:30 (ACN:H<sub>2</sub>O, <i>v</i>/<i>v</i>) could be used as general extraction methods for multiple phenolic compounds.