This paper describes an automated pyrolysis system for gas chromatography (GC) based on a filament type pyrolyzer combined with a commercially available thermal desorption instrument, onto which the pyrolysis module is installed. Automated sample introduction for both pyrolysis and thermal desorption is performed using a commercially available autosampler.
For pyrolysis of solid, liquid, or melting samples the use of different types of sample holders is investigated, for example cup-type holders for liquid samples. A special design has been developed that enables accelerated gas phase transport to help reduce the formation of secondary pyrolysis products. Sample holder design and complete flow path heating are essential design aspects in order to maximize recovery and minimize carry-over, enabling the system to reliably perform automated analysis of batches of different sample types. These aspect are discussed.
The cryo-trap function of the thermal desorption system used enables splitless transfer to the GC/MS of the formed pyrolysis products. An example is presented, in which water containing macromolecule residue in the ppm range is introduced into the pyrolysis module. The water is then removed using a solvent vent step and pyrolysis performed immediately afterwards, enabling quantification of the macromolecules by chromatographic determination of their pyrolysis products.
