Title
Non-destructive analysis of kraft pulp by NIR spectroscopy
Authors
MARIA FISEROVA ANNA ILLA and MARTA MAHOLANYIOVA

Received February 27, 2013
Published Volume 48 Issue 3-4 March-April
Keywords NIR spectroscopy, multivariate calibration, validation, unbleached beech kraft pulp, kappa number, tensile index, burst index, tear index, brightness

Abstract
A fast and convenient analytical technique is needed for quality assessment and precision management in pulp production. The main objective of this study was to evaluate the ability of NIR spectroscopy to predict diverse pulp properties. Near-infrared reflectance spectra of handsheets, prepared from unbleached beech kraft pulps obtained under different pre-extraction and pulping conditions were evaluated. The pulp characteristics were modelled using the first derivatives of optical density [log(1/R)] and the application of the partial least squares (PLS) method. The models were verified by using cross-validation and validation methodology. Kappa number, tensile index, burst index, tear index and brightness were successfully predicted by NIR spectroscopy (R > 0.90). The results indicate that NIR spectroscopy can be used as a rapid analytical technique to simultaneously estimate several characteristics with acceptable accuracy and can reduce time in conventional methods, so it could be suitable for direct applications, where “real time” data are needed.