TY - JOUR
T1 - Characterization of flavonoids by aluminum complexation and collisionally activated dissociation
AU - Zhang, Junmei
AU - Wang, Junmei
AU - Brodbelt, Jennifer S.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2005/3
Y1 - 2005/3
N2 - Aluminum complexes of the type [AlIII (flavonoid - H) 2]+ are generated by electrospray ionization in order to allow differentiation of isomeric flavonoids by tandem mass spectrometry. The dominant species observed from the aluminum complexation reaction has a 1:2 aluminum(III): flavonoid stoichiometry. Differentiation of 18 flavonoids constituting seven isomeric series was achieved based on the collisionally activated dissociation patterns of the aluminum complexes. Characteristic fragmentation pathways allow identification of the site of glycosylation, the type of saccharide (rutinose versus neohesperidose) and the type of bond between the C-2 and C-3 atoms (thus distinguishing flavanones from flavonols and flavones). Two stable coordination geometries of the aluminum complex of apigenin were identified. The non-planar structure with a plane-angle of nearly 90° is 25.3 kcal mol-1 more favorable than the planar structure. The conformations of the complexes, which involve multiple interactions between the aglycone and disaccharide portions of the flavonoid with the metal ion, are significantly different for the isomeric flavonoids.
AB - Aluminum complexes of the type [AlIII (flavonoid - H) 2]+ are generated by electrospray ionization in order to allow differentiation of isomeric flavonoids by tandem mass spectrometry. The dominant species observed from the aluminum complexation reaction has a 1:2 aluminum(III): flavonoid stoichiometry. Differentiation of 18 flavonoids constituting seven isomeric series was achieved based on the collisionally activated dissociation patterns of the aluminum complexes. Characteristic fragmentation pathways allow identification of the site of glycosylation, the type of saccharide (rutinose versus neohesperidose) and the type of bond between the C-2 and C-3 atoms (thus distinguishing flavanones from flavonols and flavones). Two stable coordination geometries of the aluminum complex of apigenin were identified. The non-planar structure with a plane-angle of nearly 90° is 25.3 kcal mol-1 more favorable than the planar structure. The conformations of the complexes, which involve multiple interactions between the aglycone and disaccharide portions of the flavonoid with the metal ion, are significantly different for the isomeric flavonoids.
KW - Aluminum complexation
KW - Collisionally activated dissociation
KW - Flavonoid diglycosides
KW - Isomer differentiation
KW - Molecular modeling
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U2 - 10.1002/jms.793
DO - 10.1002/jms.793
M3 - Article
C2 - 15674859
AN - SCOPUS:15444375987
SN - 1076-5174
VL - 40
SP - 350
EP - 363
JO - Journal of Mass Spectrometry
JF - Journal of Mass Spectrometry
IS - 3
ER -