Method For Determination Of Lignin Research Articles

ABOUT THE POSSIBILITY OF QUANTITATIVE DETERMINATION OF LIGNIN AND CELLULOSE IN PLANT MA-TERIALS USING IR SPECTROSCOPY

A methodical approach for quantitative determination of lignin and cellulose in plant materials by midinfrared FT-IR spectroscopy using the suspension method in tablets with KBr was proposed. For the prepared model binary mixtures of pure cellulose and lignin a direct correlation was achieved between the concentration and intensity of the analytical absorption bands of lignin (1508–1512 cm-1) and cellulose (1059–1061 cm-1). Based on the obtained intensity / concentration dependences formulas were derived that allow calculating the content of lignin and cellulose. The proposed method was tested on a wide range of plant biomass samples: 9 wood samples and 11 samples of agro-processing wastes. A good suitability of the proposed method for the quantitative determination of lignin was shown; the deviation from the literature data was no more than 1%. However, the proposed method was not suitable for the determination of cellulose since it didn't take into account the contribution of hemicellulose and extractive substances in the absorption band of 1059–1061 cm-1, which resulted in greatly overestimated results of cellulose content determination.

Combined methods for the determination of lignin and cellulose in leaf litter

Precise and specific methods for the simultaneous quantitative determination of lignin and cellulose are discussed in this paper, enabling the monitoring of even slight changes in the content of lignocellulose in dead plant material during decomposition processes. Results from different leaf litter samples as well as a comparison of the lignocellulose content of freshly fallen leaf litter, leached and microbially inoculated leaf litter, and feces of saprophagous soil animals fed on this food source are presented. The suitability of the described methods for investigating decomposition processes is discussed.

A simple and rapid method for determination of lignin in plant tissues—its usefulness in elicitor screening and comparison to the thioglycolic acid method

Abstract Lignification of injuries is an important component of a plant’s defense against postharvest diseases. Currently available methods for determination of lignin are slow and tedious. We describe a method to rapidly quantify lignin in plant tissue discs based on measurement of color difference following selective staining with Schiff’s reagent. The effect of elicitor treatment on accumulation of lignin at 30°C was evaluated using storage tissues of four plants. Root tissues of daikon, turnip and sweet potato all exhibited increased lignification in response to elicitation with pectinase, chitosan or a yeast extract. Acorn squash tissue responded only to pectinase. Squash tissue elicited and then held at 28°C for 18 h developed considerable resistance to infection by Penicillium italicum. Accumulation of lignin over time was determined by both the color difference method and the thioglycolic acid (TGA) method. These two methods gave very different impressions of the accumulation of lignin over time. However, each method gave very similar results on all four plants tested. As measured by the color difference method, lignin accumulation became apparent only 4 h after elicitation and the lignification process was complete within 24 h. In contrast, lignin accumulation by the TGA method was much slower, increases were not evident until 8–12 h after elicitation, and lignin continued to accumulate for a further 36 h. The difference between the results obtained with these two methods may be explained by the solubility of the lignin when first formed.

Determination of soluble lignin and proteins in the presence of each other

Several methods for the differential determination of lignin and of proteins solubilized together in the same solution are compared. It is shown that lignin is best determined by spectrophotometry at 280 nm, the absorptivity of the polymer being an order of magnitude greater than those of proteins. In contrast, a turbidimetric method applied to acid-precipitated lignin is strongly influenced by both the nature and the amounts of the proteins present in the mixture. Ninhydrin reagents permits the determination of proteins without interference from soluble lignin. Phenol and Coomassie Blue reagents react strongly with lignin, thus masking their interaction with proteins. The soluble lignin preparations used were solubilized from stake lignin in buffers adjusted to different pH values. They were analysed by exclusion chromatography and the results suggest that the lignin fragments obtained at higher pH are larger than those solubilized at lower pH. Turbidimetry showed that these larger soluble fragments form larger aggregates after acid precipitation.

The Chemistry of Wood-III - Part-Comparison of Two Methods for Determination of Lignin

The Chemistry of Wood-III - Part-Comparison of Two Methods for Determination of Lignin