To provide a method capable of separating a monofunctional species, bifunctional species, etc. of a fluorinated ether compound having a polyfluoropolyether chain and a predetermined functional group in good yield and with high separation performance.
A separation method for separating a compound represented by the formula (1) and a compound represented by the formula (2) from a mixture containing them by chromatography using a stationary phase and a mobile phase, wherein the mobile phase contains at least one type of specific solvent selected from a hydrofluoroolefin, a hydrochlorofluoroolefin, a chlorofluoroolefin, a cyclic hydrofluoroolefin, a cyclic hydrochlorofluoroolefin, a cyclic chlorofluoroolefin, a cyclic hydrofluorocarbon, a cyclic hydrochlorofluorocarbon, a cyclic chlorofluorocarbon and a perfluoroketone: