Separation method

A separation method for separating a compound represented by the following formula (1) and a compound represented by the following formula (2) from a mixture containing them by chromatography using a mobile phase and a stationary phase, which comprises

• a step of supplying the mixture to the stationary phase of the chromatography to let it be adsorbed on the stationary phase, and
• a step of supplying, to the stationary phase having the mixture adsorbed thereon, a mobile phase containing at least one type of specific solvent selected from the group consisting of a hydrofluoroolefin, a hydrochlorofluoroolefin, a chlorofluoroolefin, a cyclic hydrofluoroolefin, a cyclic hydrochlorofluoroolefin, a cyclic chlorofluoroolefin, a cyclic hydrofluorocarbon, a cyclic chlorofluorocarbon and a perfluoroketone:
• A-(OX)m—O—Z—(R)n1 Formula (1)
• (R)n2—Z—(OX)m—O—Z—(R)n3 Formula (2)
• where
• A is an alkyl group or a fluoroalkyl group,
• X is an alkylene group or a fluoroalkylene group having one or more fluorine atoms,
• m is an integer of 2 or more,
• Z is a (n1+1)-valent, (n2+1)-valent or (n3+1)-valent linking group,
• R is any functional group selected from the group consisting of —OH, —CR1═CR2R3 (where R1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R2 and R3 are each independently a hydrogen atom or a fluorine atom), —CH3, —NH2, —SH, -Ph, —F, —Cl, —Br, —I, —C≡CH and —N3,
• n1 is an integer of 1 or more,
• n2 is an integer of 1 or more, and
• n3 is an integer of 1 or more.