Distinction between 17-epimeric hydroxy steroids of the 3,17-dioxygenated androstane series by chemical ionization

The distinction between 17-epimeric 3,17-dioxygenated hydroxyandrostanes has been made by comparison of both their methane or ammonia positive and OH^? negative chemical ionization (CI) mass spectra. In the methane or ammonia positive CI, the 17α-configuration in the eight stereoisomeric 5ξ-androstane-3ξ,17ξ-diols can be determined by the relative abundances of the ion MH? 2 H₂O]⁺. In the ammonia CI spectra, the ion M+NH₄? H₂O]⁺ possesses only a low abundance, but a comparison of the relative rates of the loss of water v. the loss of ammonia from M.NH₄]⁺ in the second field-free region allows a clear distinction to be made between the 17α- and 17β-series. In the OH^? negative CI mass spectra, the 5ξ-androstane-3-one-17ξ-ols produce an intense ion M? H? H₂O]^? in the 17α-series only.