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Front cover: Magnetic separation coupled with high‐performance liquid chromatography–mass spectrometry for rapid separation and determination of lignans in Schisandra chinensis
Author(s) -
Piao Jishou,
Liu Lu,
Wang Sihong,
Shang HaiBo,
He Miao,
Quan Ninghai,
Li Donghao
Publication year - 2018
Publication title -
journal of separation science
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201870091
Subject(s) - chemistry , adsorption , salt (chemistry) , benzene , magnetic nanoparticles , citric acid , selectivity , ammonium , nanoparticle , organic chemistry , chemical engineering , engineering , catalysis
J. Sep. Sci. 2018, 41 , 2056–2063 DOI: 10.1002//jssc.201701098 The cover picture shows the selectivity between polyethyleneimine modified magnetic nanoparticles (PEI‐MNPs) and lignans by strong cation–π interaction. Lignans contain substantial amount of methoxyl and hydroxyl groups, which make them negatively charged. Polyethyleneimine modified magnetic nanoparticles are water‐soluble polycations that comprise a lot of amine functional groups. Due to the surface of MNPs that is full of −NH 3+ under the condition about pH 7, MNPs' surface is full of positive charges, leading to a strong electrostatic interaction with lignans. At the same time, the −NH 3+ groups on the PEI‐MNPs surface form a strong cation–π interaction with the benzene rings of lignans. The cation–π interaction is potentially stronger than the ammonium carboxylate salt bridges that are formed by PEI‐MNPs with interfering polar chemicals such as citric acid in aqueous media, and the several methoxyl groups on the benzene ring enhance the negative electron cloud density to increase the cation‐π interaction and electrostatic adsorption. By using these interactions, the lignans can be easily and effectively purified.