Structural characterization of flavonoid glycosides by collisionally activated dissociation of metal complexes

Collisionally activated dissociation is used for structural characterization of a series of flavonoid glycosides. Dissociation of transition metal/flavonoid binary complexes of the type [MII(L - H+)]+ and transition metal/2,2'-bipyridine/flavonoid ternary complexes of the type [MII(L - H+)bpy]+ give fragmentation patterns that are complementary and more diagnostic than those of the protonated, deprotonated, or sodium-cationized flavonoids. Analysis of fragmentation patterns of the [MII(L - H+)bpy]- complexes permits determination of the disaccharide as a rutinose or neohesperidose and the relative placement of the disaccharide (i.e., 3 vs. 7 positions).