Abstract
Thin-layer chromatography on polyamide (Nylon 6) was applied to the separation of estrone, estradiol and estriol, by using twenty-three kinds of single solvent and three kinds of binary solvent mixture.
The Rf values of estrogens with a few exceptions depended on hydrogen-bonding parameter (γ values) and solubility parameter (δ values) of the single solvent used. The Rf values became larger with increasing γ values in solvent systems with their values above 5. Solvent systems with both γ and δ values above 10 caused desorption and the thin-layer of polyamide hardly showed separation ability.
For better resolution of estrogens, the suitable developing solvent systems would be protophilic solvents with γ values above 5 or aprotic polar solvents with γ values below 5. A mixture of these or the aprotic polar solvents with an addition of a small amount of protic solvent with δ value above 10 would be also useful.
