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 [MH2 H 2 O] + . In the ammonia CI spectra, the ion [M+NH 4 H 2 O] + possesses only a low abundance, but a comparison of the relative rates of the loss of water v. the loss of ammonia from [M.NH 4 ] + 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 [MHH 2 O] − in the 17α‐series only.