Analysis of a caffeic acid derivative by ESI-MS/ MS: unexpected product ions formed by 'internal residue loss'

摘要

Oxidation reactions are of major significance in human physiology, and oxidation stress is believed to be an important contributing factor to the pathology of atherosclerosis, cancer and tissue damage in rheumatoid arthritis.~([1,2]) There is currently an intense research interest regarding phenolic compounds in the fields of food and medicine due to their free radical scavenging activity.~([3]) Caffeic acid derivatives are a kind of important phenolic acid compounds. It is necessary to develop a rapid and sensitive method for the analysis of these compounds. Recently, the application of electrospray ionization mass spectrometry (ESI-MS) or highperformance liquid chromatography (HPLC)/ESI-MS has been reported to analyze the caffeic acid derivatives.~([4-9]) Herein, a caffeic acid derivative, 4-(6-O-caffeoyl-β-D-glucopyranosyloxy)-5- hydroxyprenyl caffeate, was investigated by ESI-quadrupole time-of-flight tandem mass spectrometry (QTOF).