摘要 : High-resolution electrospray ionization multistage tandem mass spectrometry (MS1-7) in positive ion mode was used to determine the accurate masses and the fragmentation pathways of two furofurans, sesamin and gmelinol. The protona... 展开 High-resolution electrospray ionization multistage tandem mass spectrometry (MS1-7) in positive ion mode was used to determine the accurate masses and the fragmentation pathways of two furofurans, sesamin and gmelinol. The protonated molecules [M+H](+) were absent in the conventional mass spectra of both compounds, but two characteristic ions, [M+H-H2O](+) and [M+H-H-2](+), were always observed. Successive losses of CH2O and CO are the common characteristic fragmentations. Based on the exact masses acquired from 21 different tandem mass spectra, two or three fragmentation pathways for each compound are proposed. The consecutive losses of two H2O molecules and one H-2 molecule readily take place from the furan rings for both sesamin and gmelinol, resulting in the absence of the protonated molecules in the single-stage experiments. HCHO loss is observed at least three times in the tandem mass spectra, mainly from methylenedioxy groups (OCH2O) for sesamin but only from tetrahydrofuran rings for gmelinol. Moreover, CO loss is found at least three times in the tandem mass spectra of both sesamin and gmelinol from the 3,4-methylenedioxyphenyl (ArOCH2O) moieties for sesamin and from both the dimethoxyphenyl and the tetrahydrofuran ring moieties for gmelinol. In addition, the disubstituted benzyl cation ArCH2+ at m/z 135 for sesamin and at m/z 151 for gmelinol was found in the MS3 spectra of both sesamin and gmelinol, which is very helpful in the identification of the compositions of 3,4-disubstituted groups on the benzene rings of the furofurans. Copyright (C) 2007 John Wiley & Sons, Ltd. 收起