ION-EXCHANGE PURIFICATION OF ESTROGENS

With the aim of developing a method for the determination of the whole estrogen profile in biological materials, including the labile estrogens, several alternative ion exchange Chromatographie purifications have been assessed. A two-step anion exchange chromatography, first on a DEAE-Sephadex A-25 gel in the acetate form and then on the same gel in the hydroxyl form, gave the best results. The use of ascorbic acid and small columns (in Pasteur pipettes) combined with silanization of all glassware were essential for the preservation of the labile estrogens. The recovery of estrogen standards varied from 85 to 95% and no significant interconversions were detected. When estrogens were added to hydrolysed urine the recoveries were 50-90% and the extracts were pure enough for gas chromatography on capillary columns. These results can be improved by adding a further purification procedure prior to the ion exchange chromatography on DEAE-Sephadex A-25 in the hydroxyl form. © 1979.