On-line NMR detection of microgram quantities of heparin-derived oligosaccharides and their structure elucidation by microcoil NMR.
The isolation and purification of sufficient quantities of heparin-derived oligosaccharides for characterization by NMR is a tedious and time-consuming process. In addition, the structural complexity and microheterogeneity of heparin makes its characterization a challenging task. The improved mass-sensitivity of microcoil NMR probe technology makes this technique well suited for characterization of mass-limited heparin-derived oligosaccharides. Although microcoil probes have poorer concentration sensitivity than conventional NMR probes, this limitation can be overcome by coupling capillary isotachophoresis (cITP) with on-line microcoil NMR detection (cITP-NMR). Strategies to improve the sensitivity of on-line NMR detection through changes in probe design and in the cITP-NMR experimental protocol are discussed. These improvements in sensitivity allow acquisition of cITP-NMR survey spectra facilitating tentative identification of unknown oligosaccharides. Complete structure elucidation for microgram quantities of the purified material can be carried out through acquisition of 2D NMR spectra using a CapNMR microcoil probe.
Korir
Albert K
AK
Department of Chemistry, University of California, Riverside, CA 92521, USA. akorir@gmail.com
Larive
Cynthia K
CK
D006493:Heparin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation* / Q000379:methods; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry*; D009862:Online Systems
D009844:Oligosaccharides; D006493:Heparin