New features on the fragmentation and differentiation of C-glycosidic flavone isomers by positive electrospray ionization and triple quadrupole mass spectrometry.
Six flavone mono-C-glucosides, four standards (beta-D-glucopyranosyl-(1 --> C-6)- and -(1 --> C-8)- apigenin and luteolin) and two others from lemon juice (beta-D-glucopyranosyl-(1 --> C-6)- and -(1 --> C-8)-diosmetin) have been studied in order to analyze their fragmentation patterns. Initial separation was carried out using high-performance liquid chromatography with diode-array detection (HPLC/DAD) coupled to an electrospray ionization (ESI) interface and a triple quadrupole mass spectrometer. Several systematic differences between collision-induced dissociation tandem mass (CID-MS/MS) spectra of C-6- and C-8-isomers have been found and some general guidelines and two new diagnostic product ions have been proposed for the differentiation of C-6- and C-8-flavonoid glycosides. These results have been successfully applied to the characterization of two flavone C-glycosides found in lemon juice, and mass spectra of a flavone di-C-glycoside detected in lemon juice have been studied and interpreted.
Abad-García
Beatriz
B
Departamento de Quimica Analitica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, 48080 Bilbao, Spain.
Garmón-Lobato
Sergio
S
Berrueta
Luis A
LA
Gallo
Blanca
B
Vicente
Francisca
F
D047310:Apigenin / Q000032:analysis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002957:Citrus / Q000737:chemistry; D047309:Flavones / Q000032:analysis* / Q000737:chemistry*; D005419:Flavonoids / Q000032:analysis / Q000737:chemistry; D006027:Glycosides / Q000032:analysis* / Q000737:chemistry; D007536:Isomerism; D047311:Luteolin / Q000032:analysis / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013997:Time Factors
D047309:Flavones; D005419:Flavonoids; D006027:Glycosides; D047310:Apigenin; D047311:Luteolin; C039602:diosmetin