Studies on neurosteroids. Part XIII. Characterization of catechol estrogens in rat brains using liquid chromatography-mass spectrometry-mass spectrometryFor Part XII see ref. 9.

Abstract

The existence of catechol estrogens in rat brains was clarified using liquid chromatography-atmospheric pressure chemical ionization-ion trap-mass spectrometry-mass spectrometry (LC-APCI-MS²). The catechol estrogens were extracted in the presence of ascorbic acid and then derivatized to acetates with acetic anhydride and pyridine. After a successive purification with silica gel mini-column chromatography, reversed-phase solid-phase extraction and preparative HPLC, the obtained fractions containing the catechol estrogen acetates were subjected to LC-APCI-MS². 2-Hydroxyestrone, 2-hydroxyestradiol and their 4-hydroxy isomers were identified as acetates by comparison with authentic samples based on their chromatographic behavior and mass spectral data. The derivatization to acetate was useful for the treatment of labile catechol estrogens.