Recent innovations in analytical methods for the qualitative and quantitative assessment of lignin

Abstract

a b s t r a c tAs the attraction of creating biofuels and bio-based chemicals from lignocellulosic biomass has increased, researchers have been challenged with developing a better understanding of lignin structure, quantity and potential uses. Lignin has frequently been considered a waste-product from the deconstruction of plant cell walls, in attempts to isolate polysaccharides that can be hydrolyzed and fermented into fuel or other valuable commodities. In order to develop useful applications for lignin, accurate analytical instrumentation and methodologies are required to qualitatively and quantitatively assess, for example, what the structure of lignin looks like or how much lignin comprises a specific feedstock's cellular composition. During the past decade, various diverse strategies have been employed to elucidate the structure and composition of lignin. These techniques include using two-dimensional nuclear magnetic resonance to resolve overlapping spectral data, measuring biomass with vibrational spectroscopy to enable modeling of lignin content or monomeric ratios, methods to probe and quantify the linkages between lignin and polysaccharides, or refinements of established methods to provide higher throughput analyses, less use of consumables, etc. This review seeks to provide a comprehensive overview of many of the advancements achieved in evaluating key lignin attributes. Emphasis is placed on research endeavored in the last decade.

Development of Method to Determine the Concentration of Alkali-Soluble Lignin using Coomassie Brilliant Blue G-250

“…As the global effort increases to find a high-valued biorefinery route, the importance of lignin quantity determination has proven to be paramount (Lupoi et al 2015). In pulping and paper-making, and the first generation cellulosic projects, most of the lignin is combusted (Mohamad Ibrahim et al 2011;Ragauskas et al 2014).…”

Co(salen) supported on graphene oxide for oxidation of lignin

“…Figure was a brief show of the HMBC NMR spectra for the lignin, and P NMR determined a number of important phenolic structural features in lignin including . The quantification of the various phenolics obtained by P NMR was shown in Table .…”

Review on Catalytic Cleavage of C–C Inter-unit Linkages in Lignin Model Compounds: Towards Lignin Depolymerisation

“…Compared to hardwood and softwood lignins, grass lignins contain more H units [7,17,20]. For any given lignin sample, the H:G:S ratio can be calculated using wet chemical methods such as acidolysis, nitrobenzene oxidation (NBO), permanganate oxidation, cupric oxide and thioacidolysis [21][22][23] or spectroscopic techniques such as FT-IR [24] or 2D-NMR [25,26]. For example, a method for the quantitative analyses of lignin samples was reported by Kline et al using their normalized Fourier Transform Infra-Red (FTIR) spectra [24].…”