Analytical pyrolysis as a direct method to determine the lignin content in wood: Part 1: Comparison of pyrolysis lignin with Klason lignin

In this work a method for the quantification of the lignin content (Py-lignin) of Maritime pine and spruce wood samples directly from the pyrograms is presented. The precision of the Py-lignin method was 0.41% for Maritime pine (Pinus pinaster Aiton) and 0.34% for spruce (Picea abies (L.) Karst), close to the stated repeatability of the reference Klason method (0.34%). Besides apparent species-specific deviations, an average difference of 3.9 ± 0.72% compared to the Klason lignin content was observed. Py-lignin retains between 70 (Maritime pine) and 89% (spruce) of the variation in the lignin amount found for the same samples by the Klason lignin method.Good correlation was found between the Py-lignin and Klason lignin content, for both species but a good common model to both species was also found, which allows to calculate the Klason lignin content from Py-lignin content for both species using only one model.