Separation and Identification of Oil-soluble Dyes by Partition Paper Chromatography

Various oil-soluble dyes have been used in many petroleum products. The structural analysis of oil-soluble dyes is essential for identification of commercial dyes and detection of their impurities.This paper deals with the separation and identification of azo and anthraquinone oil-soluble dyes, and fluorescent oil-soluble dyes by paper chromatography.Peculiar Rf value was given to each oil-soluble dye by partition paper crhomatography using liquid paraffin or n-cetane as the the stationary phase and 80% ethyl alcohol as the mobile phase. The author found it is possible to discriminate p-dimethylamino-azobenzene having carcinogenic properties from p-diethylamino-azobenzene and to detect impurities in commercial dyes by these solvent systems.