Deciphering the structure of isomeric oligosaccharides in a complex mixture by tandem mass spectrometry: Photon activation with vacuum ultra-violet brings unique information and enables definitive structure assignment

- A complex mixture of methylated oligogalacturonans was fractionated by IP-RP-UHPLC.
- Synchrotron-radiation in VUV range was used as an activation process for tandem MS.
- VUV activation brought rich structural information compared to LE-CAD.
- Resolution of more than 35 structures, including isomers, was successfully completed.