High-performance liquid chromatography with electrospray ionization mass spectrometry and diode array ultraviolet detection in the identification of flavonol aglycones and glycosides in berries

High-performance liquid chromatography-electrospray ionization-mass spectro metry (HPLC-ESI-MS) was used to study flavonol aglycones and glycosides in berries. For the identification of aglycones, photodiode-array detection (D AD) was also used. The HPLC-ESI-MS technique is highly valuable in the iden tification of flavonol aglycones and glycosides from berry extracts. This i onization technique provides information on the structure of the aglycones and glycosides without time-consuming pre-purification or derivatization st eps. Quercetin aglycone was identified with both ESI-MS and DAD in all of t he berries studied. Myricetin aglycone was identified with both techniques in three berries. Hexose, deoxyhexose-hexose and pentose derivatives of que rcetin were the most abundant flavonol glycosides identified. Two glycoside s of myricetin and one glycoside of kaempferol were identified in blackcurr ant. To confirm the data obtained using the HPLC-ESI-MS procedure, fraction s of the glycosides from four berries were separated, hydrolyzed, silylated and the sugars were analyzed using gas chromatography-mass spectrometry. ( C) 1998 Elsevier Science B.V. All rights reserved.