Study on the Four Flavone-C-glycosides by Electrospray Ionization Tandem Mass Spectrometry

Abstract:

Objective: To study on the four flavone-C-glycosides which were vicenin-2, luteolin-6-C-glucopyranosyl-8-C-xylopyranoside, quercetin-6-C-glucopyranoside and dihydroquercetin-6-C-glucopyranoside by electrospray ionization tandem mass spectrometry (ESI-MSⁿ). Method: The samples were analyzed by ESI-MSⁿ under positive and negative ion models. Result: Under negative ion model, flavone-C-glycosides which had pentose substituent take place sugar bond cleavage and generate fragment ions (m/z 90 and 60), these which had hexose substituent generate fragment ions (m/z 120 and 90) and these which had two sugar substituents successively generate fragment ions (m/z 120, 90 and 60). Under positive ion model, flavone-C-glycosides take place dehydration,and these flavones which had pentose substituent take place sugar bond cleavage and generate fragment ions (m/z 60), these which had hexose substituent generate fragment ions (m/z 120). Conclusion: The ESI-MSⁿ methods for the identification of flavone-C-glycosides, especially which had two sugar substituents, were established.