Direct identification of phenolic glucosides from olive leaf extracts by atmospheric pressure ionization tandem mass spectrometry

Pneumatically assisted electrospray (or ionspray) coupled with liquid chromatography was applied to the identification of the phenolic glucoside content of olive leaf directly from the crude extracts. The mass spectra of the positive ions provide insights into the composition of the phenolic constituents. Oleuropein, ligstroside and a disaccharide containing the hydroxytyrosol moiety were found in olive leaf of Olea europea L. cv. Cassanese and their structures were thoroughly determined by tandem mass spectrometry.