MULTIVARIATE CHARACTERIZATION OF PULP USING SOLID-STATE 13CNMR, FTIR, AND NIR

Changes in pulp samples in chemical composition were monitored during the birch kraft pulping process using three different spectroscopic methods-C-13 CP/MAS NMR, FTIR, and NIR. The spectroscopic data were evaluated in relation to a matrix composed of chemical descriptors using multivariate methods. All these techniques could readily predict the contents of the main carbohydrate constituents (glucose and xylose) and the Klason lignin content. Although no attempts were made to optimize the analysis methods individually, NIR seems to be the best method. A suitable combination of spectroscopic data preprocessed in a multivariate way was better than any individual spectroscopic method used.