DETERMINATION OF ISOFLAVONES USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ATMOSPHERIC-PRESSURE CHEMICAL-IONIZATION MASS-SPECTROMETRY

High-performance liquid chromatography in combination with mass spectr ometric detection (atmospheric-pressure chemical ionization, APCI) was used to determine various isoflavones. Negative-ion APCI ionization h as proved to be a suitable technique for determining this class of nat ural. compound, as it provides quality mass spectra which give not onl y the molecular weight of the isoflavones, but also their molecular st ructures; consistent collision-induced dissociation pathways were eluc idated and fragments are reported. Deuterium oxide was used to induce peak shifts in the mass spectra in order to determine the number of ex changeable hydrogen atoms in each molecule.