Analysis of flavonol glycoside isomers from leaves of Maytenus ilicifolia by offline and online high performance liquid chromatography-electrospray mass spectrometry

Flavonol glycosides present in leaves of Maytenus ilicifolia, were examined after fractionation on silica-gel column. Flavonol mono-, di-, tri-, and tetraglycosides, containing kaempferol, quercetin or myricetin were identified by offline electrospray mass spectrometry. Increasing the cone energy induced to adducts variation, from H(+) to Na(+). Protonated ions were characteristically fragmented by sequentially removing the monosaccharide residues, whereas in the sodiated ions, the aglycone was firstly removed. Online high performance liquid chromatography-mass spectrometry, with simple gradients of water, acetonitrile and acetic acid indicated the presence of several isomers, which were further identified by gas chromatography-mass spectrometry as containing galactose or glucose.