Recent progress of the applications of functionalized magnetic ionic liquids in sample pretreatment

Magnetic ionic liquids (MILs) not only possess the advantageous properties of traditional ILs but also can be responsive to external magnetic fields. Their tunable structures and paramagnetic properties facilitate the integration of magnet-based technologies into analytical methods with high extraction efficiencies, good selectivities and easy phase separations through magnetic collections. The incorporations of MILs enable expedited extraction processes through magnetically enhanced phase separation, eliminating time-consuming steps such as centrifugation and filtration. These advantages have led to increasing applications of MILs in sample pretreatment methods, particularly in micro-extractions such as dispersive liquid–liquid micro-extraction, single-drop micro-extraction, aqueous two-phase extraction et al. These advanced sample pretreatment techniques have easy operation procedures, apply very little environmentally polluting organic solvents compared with traditional methods. The purpose of this review is to provide the latest literatures and achievements on MILs and the applications of MILs in sample pretreatment methods. Finally, the challenges and prospects of the developments of magnetic ionic liquids are prospected.