Abstract

Some biological and pharmacological properties of chalcones depend both on the different functional groups and their relative positions. Thus it is important to characterize their structures and to differentiate the isomers. Herein, six positional isomers of methoxychalcone were systematically studied by electrospray ionization tandem mass spectrometry (ESI-MS/MS) in positive ion mode. It was found that the substitution pattern of methoxychalcones changes the ESI-MS/MS fragmentation considerably, especially the ortho substituents. The proposed fragmentation mechanisms and interpretation of MS/MS spectral differences for protonated methoxychalcone isomers are supported by density functional theory (DFT) theoretical calculations. Overall, these results indicate that ESI-MS/MS is a very useful technique for distinguishing positional isomers of analogical isomers.  

Differentiation of isomeric methoxychalcones by electrospray ionization tandem mass spectrometry.pdf