Abstract: | The mechanism of water elimination from metastable molecular, M ? CH3˙]+ and M ? ring D]+˙ ions of epimeric 3-hydroxy steroids of the 5α-series has been elucidated. Deuterium labelling, the measurement of the translational energy released during the loss of water, and collision-induced decomposition mass-analysed kinetic energy spectrometry were the techniques used. It was found that the mechanisms of water loss from metastable M+˙ and M ? ring D]+˙ ions is different from that from M ? CH3˙]+ ions. |