Identification of components in pharmaceutical preparations was rapidly and easily performed by the combination of thin-layer chromatography and infrared diffuse reflection method. A sample solution extracted by methanol was separated on a thin-layer microplate of silica gel containing a mixed fluorescent substance. The colored portions on the plate were separated while irradiating with a wide wave ultraviolet lamp, and extracted with methanol. The extracts were mixed with KBr, dried, and its infrared spectrum was measured. The spectra thus obtained were compared with standard spectra. Even 25 μg of a component gave a distinct spectrum by the diffuse reflection method.
