Gas chromatographic analysis of acetone extractives in lodgepole pine and western hemlock TMP furnish.

Application: This paper describes a practical system for rapidly identifying a wide range of wood extractives in TMP furnish.

This study describes methods for analysis of acetone soluble wood extractives using a combination of high-resolution and low-resolution gas chromatography (GC). We demonstrate their use for western hemlock and lodgepole pine thermomechanical pulp (TMP) furnish. The methods can be adapted to other sample types to determine the major component classes of acetone soluble extractives, and other components of interest.

Previous studies involving GC analysis of wood extractives often report results only for nonpolar extractives (lipids). Many acetone soluble polar components, including oxidized resin acids, also are important to pulp and papermaking and can be readily assayed using gas chromatography. Using our approach, the initial acetone extract is separated into polar and nonpolar fractions. These are separately profiled for component class content using low-resolution GC (LRGC). For more accuracy, the nonpolar fraction is also separated into acid and neutral fractions before LRGC using solid phase extraction (SPE). Analysis of individual components in the acid fraction, including resin acids, is then possible using high-resolution GC (HRGC). The polar fraction is also analyzed using LRGC and HRGC and the composition of lignans, stilbenes, and oxidized resin acids can be obtained. Specific components can be identified using mass spectrometry and commercial standards.

Using suitable internal and external standards, the methods are reproducible and well suited to calibration and quantification. This approach can detect changes among many extractives during furnish storage and at various stages of pulp and papermaking. This type of analytical approach is needed to better understand extractives-related issues in TMP mills, including pulp self-sizing and the effects of wash water recycling.

Hanneman, now at Molecular Probes, Eugene, Oregon, USA, was at the College of Forest Resources, University of Washington, Seattle, when this study was conducted. Hrutfiord is with the College of Forest Resources, University of Washington, Seattle, and Campbell is with Weyerhaeuser Corporation, Tacoma, Washington, USA. Email Hanneman at [e-mail].