Determination acid-insoluble lignin

Colombo P, Corbetta D, Pirotta A, Ruffini G (1962) Chlorine number as a method for evaluation of lignin content of a pulp Pulp Pap Mag Can 63 T126-T140 Effland MJ (1977) Modified procedure to determine acid insoluble lignin in wood and pulp Tappi 60(10) 143-144... 

ABL contents, expressed in ferulic acid equivalents, were of the same order of magnitude as Klason and acid-insoluble lignin contents. However, this agreement was fortuitous as the ABL determination provided only... 

Chemical and Spectroscopic Analyses. Acid insoluble lignin (Klason lignin) contents of wood species before and after extractions were determined using a modified procedure suitable for small samples (35). 

Templeton, D. and Ehrman, T. (1995), Determination of acid-insoluble lignin in biomass, in Laboratory Analytic Procedure LAP-003, National Renewable Energy Laboratory, Golden, CO. 

The acid-soluble lignin contents of wheat straw and bamboo have been reported as 2 and 1.5%, respectively (Schoning and Johansson 1965). In such cases, where an accurate value for total lignin content is required, acid-soluble lignin must be determined and the value applied as a correction to the acid-insoluble lignin content. 

S Determination of Acid-Insoluble Lignin in Annual Plants,... 

Analysis of dietary fiber. Total dietary fiber including both water-soluble and water-insoluble components was analysed with an enzymic method as described by Asp et al. (18). The dietary fiber was characterized by gas-liquid chromatographic assay of monosaccharides after acid-hydrolysis and gravimetric determination of acid insoluble lignin. Uronic acids were assayed with a decarboxylation method. These analyses were performed as described by Theander and Aman (19). 

Determination of Lignin Content. Lignin content in plants (wood) is determined by direct or indirect methods (21). The direct method includes measurement of acid-insoluble (ie, Klason) lignin after digesting wood with 72% sulfuric acid to solubilize carbohydrates (22). The Klason lignin contents of representative lignifted materials are shown in Table 2. 

Soluble and insoluble lignin were determined with the NREL standard biomass analytical methods for the analysis of acid-insoluble and acid-soluble lignin inbiomass, LAP-003 and LAP-004, respectively (13-14). NREL s laboratory analytical procedure for the determination of carbohydrates in biomass, LAP-002, without correction for hydrolysis losses was performed to determine the sugar content (15). 

Feedstock material and processed solids were analyzed for glucan, xylan, arabinan, and acetyl groups by quantitative acid hydrolysis according to standard methods (25). The acid-insoluble residue was considered as Klason lignin, after correction for the acid-insoluble ash (determined by igniting the contents at 575°C for 5 h). 

Determination of Acid-Insoluble (Klason) Lignin in Wood and Pulp... 

Lignin. On acidic treatments of lignin in aqueous media, lignin condensation reactions dominate and lead to the formation of acid-insoluble residues. This principle serves as the basis for quantitative determination of lignin content in plant materials [26]. Lignin condensation reactions, however, can be minimized by using mild conditions, organic solvents, or nucleophiles. 

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