QUANTITATIVE ANALYSIS OF LIGNIN, CELLULOSE, AND HEMICELLULOSES IN PLANT MATERIALS USING IR SPECTROSCOPY AND MATHEMATICALLY MODELED CALIBRATION CURVES

The paper presents a methodology for quantitative determination of lignin, cellulose, and hemicellulose in plant biomass using Fourier-transform infrared spectroscopy, based on mathematical construction of calibration dependencies. The basis of the methodology consists in obtaining composite spectra through mathematical summation of spectra of individual components taking into account their weight content. Model calibration functions reflect the dependence of absorption intensity of analytical bands on the content of corresponding components: lignin (1490–1520 cm-1), cellulose (1308–1350 cm-1), and hemicellulose (1710–1755 cm-1). A feature of the approach is the elimination of the need for preparation of a large number of actual calibration samples, which significantly reduces the time and cost of analysis. The methodology allows to significantly reduce the time of calibration preparation compared to traditional methods, while maintaining high accuracy of analysis. The developed methodology was tested on 20 samples of plant biomass of various species, and the obtained results were compared with data from traditional methods of analysis. The results are valuable for quality control of raw materials in bioenergy and pulp-and-paper industry.