Solvent selection guide for counter-current chromatography

Abstract

Thirteen two-phases counter-current chromatography solvent systems (five not previously described for high-speed counter-current chromatography) were evaluated for relative polarity by using Reichardt's dye to measure solvachromatic shifts and by using solubility of index compounds. Three groups of systems were classified as lipophilic, polar or intermediate and a solvent selection guide was developed. Several intermediate systems appeared to have similar characteristics based on these evaluations. A method for making alternative solvent systems and determining composition of the two phases without concentration standards was described. Three of the lipophilic systems were tested for the separation of a 180-mg mixture of dimethylphthalate, dioctylphthalate and dodecyl acetate, and the hexane—acetonitrile (1:1) system was found to work best.