US EPA

1192395 

Journal Article 

Identification of coal tar dyes in cosmetics and foods using reversed phase TLC scanning densitometry 

Ohno, T; Ito, Y; Mikami, E; Ikai, Y; Oka, H; Hayakawa, J; Nakagawa, T 

1996 

1 

Eisei Kagaku / Journal of Hygienic Chemistry
ISSN: 0013-273X 

42 

1 

53-59 

WOS:A1996TZ31800007 

A simple and rapid analysis of coal tar dyes in cosmetics and foods was established using reversed phase TLC/scanning densitometry. Forty-five kinds of coal tar dyes were able to be separated completely on reversed phase TLC plates by the complementary use of 4 solvent systems. Solvent system A: acetonitrile-methanol-5% aqueous sodium sulphate solution (3:3:10, v/v), solvent system B: methyl ethyl ketone-methanol-5% aqueous sodium sulphate solution (1:1:1, v/v), solvent system C: acetonitrile-methanol-5% aqueous sodium sulphate solution (1:1:1, v/v), solvent system D: acetonitrile-dichloromethane-5% aqueous sodium sulphate solution (10:1:5, v/v). Then we measured visible absorption spectra of coal tar dyes on the developed reversed phase TLC plates by scanning densitometry to identify these coal tar dyes. The proposed method was successfully applied to the identification of coal tar dyes in commercial products. 

coal tar dye; reversed phase TLC; scanning densitometry; visible absorption spectrum; cosmetic; food