Electrochemical 19F Labelling of Technical Lignin for Enhanced NMR Analysis
EMSL Project ID
51137
Abstract
Nuclear Magnetic Resonance (NMR) is a powerful tool to analyze the structure of lignin, however the complexity of this natural mixture hinders interpretation due to substantial signal overlap in proton (1H) NMR due to the lack of chemical shift dispersion, whilst carbon (13C) NMR lacks sensitivity at natural abundance (1.1%). Fluorine (19F) NMR is an attractive alternative, with large chemical shift dispersion and a sensitivity comparable to 1H. By isotopically labelling lignin with 19F (100% abundant), it will be possible to take advantage of the enhanced sensitivity and resolution, allowing for improved NMR measurements in faster time. The method proposed here takes a recently published electrochemical method for producing fluorosulfonyl functionality from pre-existing thiols and disulfides. This functionality (R-SH, R-S-S-R') does not exist in natural lignin but does exist in some technical or commercial lignins (e.g. Kraft) produced with sulfuric acid.Our primary aim is to: Develop an electrochemical stable isotope (19F) labelling methodology for lignin, with progressive objectives to a) evaluate this reaction on lignin-like model compounds, b) evaluate this reaction on several technical lignins, c) implement and apply state-of-the-art NMR experiments to probe the structural information yielded by this new label. The success of this project will expand the analytical toolkit for thiol and disulfide containing mixtures – including other natural organic matter, peptides and proteins - by NMR and high-resolution mass spectrometry (e.g. FTICR MS).-
Project Details
Start Date
2019-10-01
End Date
2021-03-31
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members