Laser desorption/Fourier transform mass spectrometry of steroids

Mass spectra of six representative underivatized steroids and three parent hydrocarbons were obtained using laser desorption/Fourier transform (LD/FT) mass spectrometry. The carbonyl steroids, with the exception of aldosterone, yielded abundant [M + H]+ ions. For cholesterol, a major fragment ion was that corresponding to dehydration. The hydrocarbons produced [M + H]+, M+ and [M - H]+ ions, in addition to expected alkyl cleavage ions including those resulting from methyl loss. The LD/FT mass spectra of all were qualitatively similar to electron ionization spectra, but showed somewhat less fragmentation.