Lignins analysis

Oxidant consumption methods, in residual lignin analysis, 75 8 Oxidants... 

Lignin quantitation was based upon a modified procedure of Johnson, Moore, and Zank (7) and van Zyl (8). In the STS-3 experiment eight seedlings from each PGC (every other seedling) were selected for lignin analysis. In the STS-51F experiment, five seedlings from each PGC were... 

Lu, F., and Ralph, J., 1997, Derivatization followed by reductive cleavage (DFRC method), a new method for lignin analysis protocol for analysis of DFRC monomers, J. Agr. Food Chem. 45 2590-2592. 

Filley, T.R. (2003) Assessment of fungal wood decay by lignin analysis using tetra-methylammonium hydroxide (TMAH) and 13-labelled TMAH thermochemolysis. In Wood Deterioration and Preservation Advances in Our Changing World (Goodell, T., Nicholas, A., and Schultz, C., eds.), pp. 119-139, ACSociety, Series 845, American chemical Society, Washington, DC. 

To prepare a pulp for Klason lignin analysis, a sample equivalent to approximately 10 g oven-dry is disintegrated in a blender or ground to pass a 10- to 20-mesh screen. Pulps which do not contain coarse fibers or shives and which can be dispersed in sulfuric acid readily may be used without prior disintegration. 

The curve-fitting calibration technique is a process whereby sample spectra are modeled as linear combinations of constituent spectra. This procedure is better suited for the analysis of a mixture of known components than for complex biopolymers such as lignin. Nevertheless, ongoing successful work throughout the world on the calibration of FTIR data with those of wet chemistry demonstrates that FTIR spectroscopy can be a powerful tool for quantitative (or at least semi-quantitative) lignin analysis. 

These idealized structures were generated based on lignin analysis, and they contain several dimer units ... 

Lignin Analysis. Lignin present in fulvic and humic acids from stream, foam, and foam-extract samples from Como Creek and the Suwannee River were oxidized to phenolic oxidation products by copper oxide oxidation via the method described by Hedges and Ertel (24). These phenolic oxidation products then were derivatized to trimethyl silyl derivatives for GC/MS analysis. 

NBO is still probably the most commonly employed chemical degradation technique for lignin analysis. This acceptance is related to the fact that NBO provides in satisfactory yield p-hydroxybenzaldehyde, vanillin, and syringaldehyde from lignin H, G, and S units, together with smaller amounts of the corresponding benzoic acids (Figure 2.2). In addition, NBO yields small amount of 5-carboxyvanillin,... 

F Lu, J Ralph. DFRC method for lignin analysis. 1 New method for (3-aryl ether cleavage Lignin model studies. J AgrFood Chem 45 4655 660, 1997. 

F Lu, 1 Ralph. The DFRC method for lignin analysis 2. Monomers from isolated lignins. JAgr Food Chem 46 547-552, 1998. 

L Zhang, W Wafa-Al-Dajani, G Gellerstedt. Comparison between different methods for qnantitative lignin analysis. Proceedings of the 7th European Workshop on Lignocellnlosics and Pulp, Turku, Einland, 2002, pp. 521-524. 

F Ln, J Ralph. The DFRC method for lignin analysis 7. Behavior of cinnamyl end gronps. J Agr Food Chem 47 1981-1987, 1999. 

Transient infrared spectroscopy (TIRS) is a mid-infrared technique [82] that has been developed to obtain spectra of moving solids and viscous liquids. TIRS spectra are obtained from the generation of a thin, short-lived temperature differential that is introduced by means of either a hot or cold jet of gas. When a hot jet is used, an emission spectrum is obtained from the thin, heated surface layer. This technique is known as transient infrared emission spectroscopy (TIRES). When a cold jet is used, the blackbody-like thermal emission from the bulk of the sample is selectively absorbed as it passes through the thin, cooled surface layer. The result is a transmission spectrum convoluted with the observed thermal spectroscopy. This method is known as transient infrared transmission spectroscopy (TIRTS). TIRS is ideally suited for online analysis because it is a single-ended technique that requires no sample preparation. This technique has been applied to the lignin analysis of wood chips [83]. 

Since mid-IR spectroscopy has been used for a long time in lignin analysis, the IR features of lignin have been studied extensively. Most bands have been previously assigned [4,65], and it has been reported that the coupling of different vibrational modes exists in the spectra. Spectra of black spruce and aspen MWLs are typical of softwood and hardwood MWLs (Figure 4.2). These spectra were obtained in the... 

Raman, mid-IR, and near-IR techniques have played an important role in lignin analysis. These techniques provide fundamental knowledge at the molecular level, and will likely continue to be used in this way. Recent developments in Raman instrumentation have made this method even more versatile and user-friendly. Specific... 

UP Agarwal, RS Reiner, and SA Ralph. Using Nano- and Micro-Particles of Silver in Lignin Analysis. TAPPI International Conference on Nanotechnology, Atlanta, 2006, pp. NanoCD-06. 

Source Landucci, L.L., Holzforschung, 45(6), 425-432, 1991. Standard samples supplied for Round-Robin Lignin Analysis at lEA Symposium, New ... 

The concepts of precision and accuracy are sometimes misunderstood as they relate to lignin analysis. The most important of these concepts is precision, as this is a prerequisite to accuracy. Simply defined, precision is the ability to reproduce a result. If... 

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