Structural Characterization of Flavonols and Flavanones in Nanogram Quantities by API-ionspray Tandem Mass Spectrometry

API-ionspray MS and tandem MS/MS techniques were utilized to elucidate the structures of ten flavonoids consisting of five flavonols-morin, and one O-methyl and three acetyl derivatives, and five flavanones-desmethoxymatteucinol, and one acetyl and three O-methyl analogs. Morin and desmethoxymatteucinol were isolated and identified previously from the barks of Vanieria cochinchinesis Lour. (Moraceae) and the flowers of Eugenia javanica Lam. (Myrtaceae), respectively, based on the UV, IR, NMR, EI-MS and derivatization data. In this investigation, apparent protonated molecular (MH^+), MNH4^+, MNa^+ and MK^+ ions in the Q1 Scan MS spectra, and prominent as well as diagnostic product ions for structural elucidation in the tandem MS/MS spectra were observed for all investigated flavonoids each in nanogram quantities.