Abstract: Considering the growing importance of the determination and identification of (desulfo-)glucosinolates in extracts of plant materials, rapid screening methods for desulfoglucosinolates were developed, based on thermospray liquid chromatography-mass spectrometry (LC-MS) and LC-MS-MS. In thermospray LC-MS the screening of plant extracts containing various desulfoglucosinolates can be based on the group-specific fragment at m/z 214, but identification of the peaks is not always straightforward owing to the lack of compound-specific fragments in the mass spectra. Using a constant neutral loss of 162 a.m.u., corresponding to the loss of the sugar ring, in thermospray LC-MS-MS the screening and identification of the various desulfoglucosinolates gives better results, especially because the signal in the MS-MS mode is less dependent on the fluctuating thermospray conditions. In some applications direct thermospray MS-MS analysis of mixtures, injected in the flow injection mode, can give satisfactory results.