AbstractThe 25eV mass spectra of the trialkylsilyl (R = Et, Pr, Bu) derivatives of several alcohols, steroids and cannabinoids are compared with those of the corresponding trimethylsilyl (TMS) derivatives. Abundant ions produced by elimination of one of the alkyl groups characterize most of the spectra. Although the presence of such ions is advantageous in certain cases, such as for single ion monitoring studies, the spectra usually contain fewer ions of diagnostic use than the spectra of corresponding TMS derivatives. Successive elimination of CnH2nfragments is also a feature of these spectra.