A comparison of C-glycosidic flavonoid isomers by electrospray ionization quadrupole time-of-flight tandem mass spectrometry in negative and positive ion mode

作者：Guo Xuefeng; Yue Yongde^*; Tang Feng; Wang Jin; Yao Xi; Sun Jia

来源：International Journal of Mass Spectrometry, 2013, 333: 59-66.

DOI：10.1016/j.ijms.2012.08.035

• Tandem mass spectrometry
• C-glycosidic flavonoid isomer
• Collision-induced dissociation
• Electrospray ionization

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](-), [X-0.3(0)-H](-) and [X-0.3(0)-H-H2O](-) in product ion mass spectra (MS/MS) of precursor ion [M-H](-) in negative ion mode, the product ions [M+H-4H(2)O](+) [X-0.3(0)+3H-2H(2)O](+), [X-0.4(0)+H-H2O](+), [M+H-H2O](+), [M+H-2H(2)O](+), [M+H-3H(2)O](+), [X-0.2(0)+H](+) [X-0.1(0)+H](+) and [X-0.4(0)+H-2H(2)O](+) in product ion mass spectra (MS/MS) of precursor ion [M+H](+) in positive ion mode.

• 出版日期2013-1-1