The identification of desulfoglucosinolates using thermospray liquid chromatography/mass spectrometry

A method for the identification of desulfoglucosinolates (DSGSs) derived from glucosinolates in plant material by thermospray liquid chromatography/mass spectrometry (LC/MS) is described. In order to assess the usefulness of the method, positive and negative ion spectra for several reference DSGSs are recorded and studied. Ions at m/z 180 and m/z 214 (positive ion mode) are present in the spectra of all the DSGSs investigated and indicate the glucosyl and thioglucosyl moieties, respectively. Ions (M+ H)+, (R - C = NOH)+, (R - C = NOH + H)+, (R - C = NOH + 2H)+, (R - N = C = O + NH4)+, and (R - C( = N - OH) - S + 2H)+, which provide side chain \u201cR\u201d information, are also observed. In the case of 3-indolylmethyl DSGSs, an additional ion R + is observed as the base peak. In the negative ion mode, ions are observed at m/z 195 and m/z 221, indicating the thioglucosyl moiety as well as an ion corresponding to (R - C( = NOH) - S)-, which gives additional mass data pertaining to the side chain. Results from the analysis of a leaf extract of Brassica juncea var. Cutlass show the presence of at least seven DSGSs.Peer reviewed: YesNRC publication: Ye