Abstract: | The CH4 chemical ionization (CI) spectra of several keto-steroids are reported as well as the H2 and C3H8CI spectra of a few keto-steroids. [M + H ? H2O]+ is an abundant ion in the CH4CI spectrum of 5α-androstane-17-one and the water loss from the [M + H]+ ions does not involve the hydrogens on C-18 and only involves the C-16 hydrogens to about 10%. The major loss process has not been determined.3-Keto and 17-Keto steroids are readily distinguished by their CH4CI spectra. The effectiveness of substituents for directing attack by [CH5]+ and [C2H5]+ can be estimated:carboxyl > methoxy ? carbonyl > bromo ? chloro > hydroxy. Significant differences are observed in the H2CI spectra of two 5α-vs. 5β-steroids. Propane CI Spectra are similar to methane CI spectra, but show generally less fragmentation. |