Translational energy release and stereochemistry of steroids. 14. Epimeric dihydroxy steroids of the androstane series

The stereochemistry of dihydroxy steroids, both the mode of the A/B ring junctions and the configuration of OH groups, may be determined from translational energy (T50%) measurements for the loss of a CH.3 radical, from the ratios of metastable-ion peak heights to those of the main beam (determined for the dehydration reactions), and by comparing unimolecular and collision-induced, mass-analysed ion kinetic energy spectra of the new main beam of [M-H2O]+ ions (i.e. those formed via dehydration of metastable molecular ions of epimeric hydroxy steroids in the first field-free region of a double-focusing mass spectrometer.