Chemometric Model for Rapid Determination of Syringyl/Guaiacyl Ratio in Non‐Wood by FT‐NIR Spectroscopic Data

The present study is to develop a cost-effective, non-destructive and rapid method for quantification of syringyl/guaiacyl (S/G) ratio content in non-wood lignin, which is based on FT-NIR spectroscopic data and chemometric modelling techniques. The S/G ratio in 22 non-wood lignins was determined by wet chemical method. Then the same samples were run with FT-NIR, and the spectroscopic data were pre-processed with Savitzky-Golay (S-G) on their 1st and 2nd derivatives. As chemometric models, principal component regression (PCR) and partial least square regression (PLSR) were assessed for quantification of S/G ratio in non-wood lignin with raw and pre-treated FT-NIR spectral data. Finally, for quantification of S/G ratio, PLSR showed the best predictive results (<i>R</i> ² = 99.90%) with FT-NIR data after treating them with S-G filtered with its derivatives and leverage correction. This rapid and cost-effective method is being proposed for the determination of S/G ratio in non-wood lignin.