Determination of carboxyl groups in wood fibers by headspace gas chromatography

Abstract

The phase reaction conversion (PRC) headspace gas chromatographic (HSGC) technique was employed to develop a method for the determination of the content of carboxyl groups in wood fibers. Acid treatment of the wood fibers using hydrochloric was applied to convert carboxyl groups to carboxyl acids. Bicarbonate solution is then used to react with carboxyl acids on the treated fibers in the headspace of a testing vial to form carbon dioxide that is analyzed by a thermal conductivity detector using gas chromatography. The conversion reaction was conducted at 60oC for about 10 minutes to achieve near complete conversion. The contribution to GC detector signal from carbon dioxide formed by residual hydrochloric acid on wood fibers can be accounted for from the known experimental parameters. The effect of carbon dioxide in the headspace of the testing vial air was calibrated or can be eliminated by purging the testing vial using nitrogen before experiment. The measured contents of carboxyl groups in 8 wood fiber samples were in good agreement with those measured by a titration method. The present method is accurate, rapid, and automated.

Citation

Chai, X.-S.; Hou, Q.X.; Zhu, J.Y.; Chen, S.-L.; Wang, S.F.; Lucia, L. 2003. Determination of carboxyl groups in wood fibers by headspace gas chromatography. 12th ISWPC International Symposium on Wood and Pulping Chemistry : Madison, Wisconsin, June 9-12, 2003, proceedings. Volume III, Poster Presentations. [Madison, WI : University of Wisconsin--Madison, Dept. of Forest Ecology and Management, 2003]: Pages 47-50