Heparin-like glycosaminoglycan/amine salt-bridge interactions: a new potential tool for HLGAGs analysis using mass spectrometry.

Characterization of glycosaminoglycans poses a challenge for current analytical techniques, as they are highly acidic, polydisperse and heterogeneous compounds. The purpose of this study is the separation and analysis of a partially depolymerized heparin-like glycosaminoglycan by on-line ion-pairing reversed-phase high-performance liquid chromatography/electrospray mass spectrometry. The gas-phase behavior of two synthesized glycosaminoglycans has been investigated. Dibutylamine was found to be the best suited ion-pairing reagents for mass spectrometry analysis. The optimized ion-pairing conditions provide reproducible and easily interpretable electrospray mass spectra in both negative and positive ESI modes. The glycosaminoglycans are detected as a non-covalent complex with amines. In fact, the observed ionic species and their gas-phase dissociation under CID conditions revealed the presence of salt bridge interactions in the gas phase.