Development of a quantitative method for the analysis of neutral saccharides in wood pulp using analytical pyrolysis

Abstract

Traditional methods for the determination of the neutral saccharide composition of complex biomaterials such as wood pulp are difficult and time-consuming. By comparison analytical pyrolysis techniques offer the advantages of speed and simplicity. Under the appropriate conditions, pyrolysis yields products that retain the stereoconfiguration of the parent neutral saccharide (the anhydrosugars). The objective of this investigation was to develop a method to quantitate the neutral saccharides in wood pulp using on-line pyrolysis - gas chromatography (Py-GC). Initial efforts focussed on maximizing the yields of anhydrosugars from isolated polysaccharides resembling those found in wood. Factors such as pyrolysis temperature and cation-exchange were investigated. Next, a variety of wood pulps of differing composition and origin were investigated by Py-GC. The numerous pyrolyzates produced by these pulps were characterized by Py-GC-MS using both electron impact (EI) and chemical ionisation (CI). Finally, Py-GC methods were developed to quantify the saccharide compositions of the pulps. Comparisons were made with results obtained by acid hydrolysis - derivatization /gas chromatography. Two on-line pyrolyzers, the CDS Pyroprobe 120® and the SGE Pyrojector®, were compared as to their suitability for quantitative analysis.