Determination of Hardwood/Softwood Content in Wood Products by Near-Infrared Spectroscopy

Near-infrared spectroscopy (NIRS) is ideally suited to monitor the hardwood and softwood content in pulp and paper products. The method described in this application note bases on the fact that the changes in hardwood and softwood content are reflected in the intensity of the absorption bands of cellulose. A linear least-squares regression on second derivative spectra provides results that correspond very well with those of conventional laboratory determinations. With NIRS, an analytic method is available that provides results in real time.