کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1192729 | 1492287 | 2013 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: A comparison of C-glycosidic flavonoid isomers by electrospray ionization quadrupole time-of-flight tandem mass spectrometry in negative and positive ion mode A comparison of C-glycosidic flavonoid isomers by electrospray ionization quadrupole time-of-flight tandem mass spectrometry in negative and positive ion mode](/preview/png/1192729.png)
Flavonoid C-glycosides are important bioactive natural compounds. They often occur as 6-C and 8-C isomers, which makes the structural elucidation difficult. In this paper, the high resolution electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI Q-TOF MS/MS) was employed to distinguish two pairs of isomeric C-glycosidic flavonoids, isoorientin (luteolin-6-C-glucoside), orientin (luteolin-8-C-glucoside), isovitexin (apigenin-6-C-glucoside), and vitexin (apigenin-8-C-glucoside), in negative and positive ion mode with different collision energy (collision-induced dissociation, CID). The two pairs of isomers can be distinguished via product ion mass spectra (MS/MS) of precursor ion [M−H]− and [M+H]+. The results demonstrated that these diagnostic characteristic ions used to identify the differences between 6-C and 8-C isomers were as follows: the product ions [M−H−H2O]−, [0,3X0−H]− and [0,3X0−H−H2O]− in product ion mass spectra (MS/MS) of precursor ion [M−H]− in negative ion mode, the product ions [M+H−4H2O]+, [0,3X0+3H−2H2O]+, [0,4X0+H−H2O]+, [M+H−H2O]+, [M+H−2H2O]+, [M+H−3H2O]+, [0,2X0+H]+, [0,1X0+H]+ and [0,4X0+H−2H2O]+ in product ion mass spectra (MS/MS) of precursor ion [M+H]+ in positive ion mode.
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► Two pairs of isomeric C-glycosidic flavonoids were distinguished by Q-TOF.
► The diagnostic ions in negative ion mode were [M−H−H2O]−, [0,3X0−H]− and [0,3X0−H−H2O]−.
► The diagnostic ions in positive ion mode were [M+H−4H2O]+, [0,3X0+3H−2H2O]+, [0,4X0+H−H2O]+, [M+H−H2O]+, [M+H−2H2O]+, [M+H−3H2O]+, [0,2X0+H]+, [0,1X0+H]+ and [0,4X0+H−2H2O]+.
Journal: International Journal of Mass Spectrometry - Volume 333, 1 January 2013, Pages 59–66