Related Experiment Video
Updated: Aug 29, 2026

Quantitative and Qualitative Method for Sphingomyelin by LC-MS Using Two Stable Isotopically Labeled Sphingomyelin Species
Published on: May 7, 2018
Differentiation of flavonoid glycoside isomers by using metal complexation and electrospray ionization mass
Michael Pikulski1, Jennifer S Brodbelt
1Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712-0165, USA.
Abstract:
The elucidation of flavonoid isomers is accomplished by electrospray ionization tandem mass spectrometry (ESI-MS/MS) via formation and collisional activated dissociation (CAD) of metal/flavonoid complexes containing an auxiliary ligand. Addition of a metal salt and a suitable neutral auxiliary ligand to flavonoids in solution results in the formation of [M(II) (flavonoid-H) ligand]+ complexes by ESI which, upon collisional activated dissociation, often result in more distinctive fragmentation patterns than observed for conventional protonated or deprotonated flavonoids. Previously, 2,2'-bipyridine was used as an auxiliary ligand, and now we compare and explore the use of alternative pyridyl ligands, including 4,7-diphenyl-1,10-phenanthroline. Using this technique, three groups of flavonoid glycoside isomers are differentiated, including glycosides of apigenin, quercetin, and luteolin.
Related Concept Videos
Mass Spectrometry: Complex Analysis
GC–MS is a powerful hyphenated method commonly used in forensics and environmental...
Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
High-Resolution Mass Spectrometry (HRMS)
Chemical Ionization (CI) Mass Spectrometry
Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Mass Spectrometry: Isotope Effect

