Ionic liquids (ILs) have been receiving much attention in many fields of analytical chemistry because of their various interesting properties which distinguish them from volatile organic compounds. They offer both directional and non-directional forces towards a solute molecule and therefore act as excellent solvents for a wide range of polar and non-polar compounds. Because of the presence of various possible interactions, ILs easily undergo biphasic separation with water and other less polar/non-polar organic solvents. Their ability to create biphasic splitting makes them a promising candidate for liquid–liquid separation processes, such as aqueous biphasic systems and liquid–liquid equilibria. Various aspects of ILs in these separation methods are discussed in view of the origin of physical forces responsible for the biphasic interactions, the effect of structural components, temperature, pressure, pH and additives. The specific advantages of using ILs in aqueous biphasic systems and liquid–liquid equilibria in binary and ternary systems are discussed with a view to defining their future role in separation processes by giving major emphasis on developing non-toxic ILs with physical and solution properties tailored to the needs of specific sample preparation techniques.

离子液体（ILs）由于其各种有趣的特性而与挥发性有机化合物区分开来，因此在分析化学的许多领域中都受到了广泛的关注。它们提供对溶质分子的方向性和非方向性作用力，因此可作为各种极性和非极性化合物的优异溶剂。由于存在各种可能的相互作用，因此IL容易与水和其他极性较小/非极性的有机溶剂发生双相分离。它们产生双相分裂的能力使其成为液-液分离过程的有前途的候选者，例如水性双相系统和液-液平衡。鉴于引起双相相互作用的物理力的来源，讨论了这些分离方法中IL的各个方面，结构成分，温度，压力，pH和添加剂的影响。讨论了在水性双相系统中使用IL以及在二元和三元系统中使用液-液平衡的特定优势，以通过重点开发具有针对性的物理和溶液性质的无毒IL来定义其在分离过程中的未来作用。特定样品制备技术的需求。