An optical disk apparatus according to the present invention includes an optical pickup device and a control section for controlling an operation of the optical pickup device. A turntable is installed to be rotated about a rotary shaft with respect to the support part, a plurality of rim placing parts on which a rim assembly is placed are provided to the turntable about the rotary shaft, and reading parts are attached to the support part at a lower side of the turntable. The column is eluted with ethyl acetaten-hexane, and after evaporating the solvent from the eluate collected, a purified ferrocenyl substituted styrene is obtained.