Application of off-line pyrolysis with dynamic solid-phase microextraction to the GC-MS analysis of biomass pyrolysis products

Pyrolysis coupled with dynamic solid-phase micro extraction (Py-SPME) followed by CC-MS analysis was applied to the determination of volatile compounds evolved by a micro-scale off-line pyrolysis apparatus, in order to extend the information affordable with this type of analytical equipment. The Py-SPME method with a carboxen/PDMS fiber working in the retracted mode was tested on four biomass samples (switchgrass, sweet sorghum, corn stalk and poplar) for qualitative analysis of semi-volatile pyrolysis products and quantitative determination of main volatiles (C-1-C-4) pyrolysis products. The developed procedure allowed capturing and analysis of all GC analyzable compounds, without memory effects and with good peak resolution also for early GC-eluting compounds. Twelve main volatile pyrolysis products, including hydroxyacetaldehyde and acetic acid, were successfully quantified: in spite of the intrinsic variability introduced by dynamic SPME sampling, results were relatively accurate and consistent with literature data on bench pyrolysis reactors. (C) 2009 Elsevier B.V. All rights reserved.