Evaluation of surface lignin on cellulose fibers with XPS

XPS measurement of carbon and oxygen signals can be used in monitoring the surface lignin content of extracted wood pulp. However, surface analyses ba sed on carbon and oxygen signals only may be unreliable due to surface cont amination We have evaluated the lignin content in over 250 chemical and mec hanical pulp samples with XPS using two different analyses, in order to stu dy the reliability and the reproducibility of the methods. The results indi cate that under a stripe experimental setup, surface contamination can be c ontrolled. Both methods of analysis turn out to be consistent indicators I surface Lignin content for a variety of extracted pulps processed under dif ferent conditions. (C) 1999 Published by Elsevier Science B.V. All rights r eserved.