A CONVENIENT METHOD FOR THE DETERMINATION OF WOOD EXTRACTIVES IN PAPERMAKING PROCESS WATERS AND EFFLUENTS

An analytical procedure has been developed which enables convenient qu antitative determination of wood extractives and lignins in papermakin g process waters. The method comprises centrifugation to remove fibres , fines and other non-colloidal particles from dissolved and colloidal substances, extraction with methyl tert.-butyl ether (MTBE), silylati on, gas chromatography (GC) to determine the amount of extractives, an d ultraviolet (UV) spectrophotometry to determine the amount of lignin s. Both lipophilic and phenolic low-molecular-mass components are extr acted in high yield by MTBE. The extractives are analyzed by GC with a utomatic on-column injection of silylated samples on a short, thin-fil m capillary column, providing direct determination of free fatty and r esin acids, sterols, steryl esters, triglycerides and lignans. Finally , the amount of dissolved lignins is determined from the UV absorption value at 280 nm of the extracted water sample. The method is convenie nt for analysis of several water samples in parallel.