Solution-State 2D NMR Spectroscopy of Plant Cell Walls Enabled by a Dimethylsulfoxide-d6/1-Ethyl-3-methylimidazolium Acetate Solvent

Lignocellulosic biomass is composed of the polysaccharides cellulose and hemicellulose and the polyphenol lignin. Many current methods for analyzing the structure of lignocelluloses involve a sequential extraction of the material and subsequent analysis of the resulting fractions, which is labor-intensive and time-consuming. The work presented here assesses the dissolution of whole lignocellulosic material, focusing on biomass derived from the perennial bioenergy grass Miscanthus. The solvent dimethylsulfoxide (DMSO)-d6 containing 1-ethyl-3-methylimidazolium acetate ([Emim]OAc) was able to dissolve lignocellulosic material completely and gave high-resolution 2D heteronuclear single quantum coherence (HSQC) NMR spectra of the entire array of wall polymers. Extrapolated time-zero HSQC was applied using DMSO-d6/[Emim]OAc-d14 and enabled quantitative analysis of structural traits of lignocellulose components.