Weisz A, Langowski A J, Meyers M B, Thieken M A, Ito Y
Division of Colors and Cosmetics, Food and Drug Administration, Washington, DC 20204.
J Chromatogr. 1991 Jan 18;538(1):157-64. doi: 10.1016/s0021-9673(01)91633-4.
A centrifugal counter-current chromatographic method for preparative purification of commercial tetrabromotetrachlorofluorescein and Phloxine B (D&C Red Nos. 27 and 28, respectively) was developed. Ethyl acetate-n-butanol-0.01 M ammonium acetate (1:1:2) was used as the two-phase solvent system. Each purification trial involved 50 mg of sample and yielded 22 mg (+/- 2 mg) of pure dye. The purity of the product was measured by high-performance liquid and thin-layer chromatography and was found to be 99.9%. The partition coefficients of these compounds were found to be highly concentration-dependent in the two-phase solvent system used. If this problem can be circumvented, then the counter-current chromatographic method can be extended for use with gram quantities of dye.
