Ionic liquids (ILs) are a class of nonmolecular substances, comprised completely of ions. Due their unique properties, including electric conductivity, low volatility, thermostability and tunability, considerable interest has been drawn for their utilization in various fields, such as synthetic chemistry, material chemistry, catalytic chemistry and spectroscopy. ILs containing imidazolium cation have been a research focus of significant importance in separation science on account of their excellent physic-chemical properties. A new type of HPLC stationary phases of great chromatographic value involving immobilization of ILs, i.e. surface-confined ILs (SCILs), has gained ever-growing attention [1-5].
    Due to imidazolium’s characteristic as typical strong cation, SCIL stationary phases can be employed in ion-exchange mode to fulfill separation of diverse organic ions. Because of their structural features, a combination of molecular mechanisms can be exploited to facilitate their application in reversed-phase mode, including hydrophobic, π-π, dipole-dipole and hydrogen bonding interactions, plus shape and planar recognition. Apart from employment in ion-exchange and reversed-phase modes, there is a promising prospect that SCIL stationary phases will play a valuable role in hydrophilic interaction liquid chromatography. With the advancement of chromatographic investigation into ILs, it is believable that SCIL stationary phases shall even benefit the separation science.
    H. Qiu acknowledges the support of the Hundred Talents Program of Chinese Academy of Science. This work was also partly supported by the National Nature Science Foundation of China (Nos. 21105107 and 21175143).

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