G. Jungbluth et W. Ternes, HPLC separation of flavonols, flavones and oxidized flavonols with UV-, DAD-, electrochemical and ESI-ion trap MS detection, FRESEN J AN, 367(7), 2000, pp. 661-666
The cation-induced or electrochemical oxidation of flavonols has been repor
ted to yield 2-(hydroxybenzoyl)-2-hydroxy-3(2H)-benzofuranones. Two new gra
dient reversed phase HPLC methods are presented which allow the determinati
on of those oxidized flavonols simultaneously with flavonols and flavones.
UV and electrochemical detection are used because of their high sensitivity
. Qualitative detection together with quantification of all compounds is ac
hieved with photodiode-array detection. An electrospray ionization ion trap
mass spectrometric method is presented for unique identification of the be
nzofuranones after HPLC separation.