Agilent Technologies Europe has released an application note titled 'Application of LC/MS with ESI to Glycosylated Natural Products', publication number 5988-3844EN
This application note demonstrates the suitability of coupled liquid chromatography and mass spectrometry (LC/MS) with electrospray ionisation (ESI) source in negative ion mode for the investigation of oligosaccharide sequencing in glycosylated products.
An Agilent 1100 LC/MS with ESI in negative ion mode was used to analyse extracts of the Hostas plant under various experimental conditions.
A detailed mass spectral study is presented on selected compounds in this analysis.
The technique yields intense negative ions of the [M-H]- variety that possess excellent ion fragmentation properties.
This fragmentation allows the sequence of the oligosaccharide moiety on the compound to be readily investigated.
A fragmentor voltage of 400V provided excellent mass spectra showing a series of ion fragments consistent with successive losses of glycosyl units.
It was concluded that the flavanoids present in the Hostas variety of plants are in the form of a series of extensively glycosylated compounds.
The sequencing of oligosaccharides is a major goal in the field of glycosylated natural products.
Prior attempts to do so, using LC/MS with ESI on samples derived from such products, have encountered serious complications.
For example, the application of ESI in positive ion mode often leads to extensive formation of [M+Na]+ ions for heavily glycosylated compounds. These ions do not lend themselves to elegant fragmentation for many classes of glycosylated compounds.
This application note is available without charge from any Agilent sales office or from the Agilent website.
