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Determination of the Syringyl/Guaiacyl Ratio of Eucalyptus Globulus Wood Lignin by near Infrared-Based Partial Least Squares Regression Models Using Analytical Pyrolysis as the Reference Method

2011; SAGE Publishing; Volume: 19; Issue: 5 Linguagem: Inglês

10.1255/jnirs.946

1751-6552

Ana Alves, Rita Simões, Desmond J. Stackpole, René E. Vaillancourt, BM Potts, Manfred Schwanninger, José Carlos Rodrígues,

Spectroscopy and Chemometric Analyses

High syringly/guaiacyl (S/G) ratios are advantageous for chemical pulp production due to higher delignification rates, higher pulp yields and lower chemical consumption. Near infrared-based partial least-squares regression (PLS-R) models were developed to assess the S/G ratio of Eucalyptus globulus wood using analytical pyrolysis as the reference method. The PLS-R models obtained using the wavenumber range from 6100cm −1 to 5450cm −1 (1639–1835nm) of the preprocessed spectra using first derivative (1stDer) and first derivative in combination with; vector normalisation (1stDerVN), multiplicative scatter correction (1stDerMSC) and straight-line-subtraction (1stDerSLS), and the second derivative (2ndDer), are well qualified for rapid screening the S/G ratio of Eucalyptus globulus wood. Overall, models using 1stDerVN and 1stDerMSC preprocess (78 samples) requiring only three PLS components have the best statistics with coefficient of determination ( r 2 ) = 0.97, root mean square error of cross-validation ( RMSECV)=0.025 and residual prediction deviation ( RPD) = 5.7