In pyrolysis (Py), the sample material is strongly heated in an inert gas environment under controlled conditions to induce thermal decomposition. This breaks down high molecular weight compounds into smaller fragments. These fragments are then separated using gas chromatography (GC) and detected using mass spectrometry (MS). Using the resulting mass spectra of the fragments produced during pyrolysis, it is possible to identify them and determine their structure. Conclusions can then be drawn about the composition of the starting material from the characteristic decomposition products.
The advantage of Py-GC-MS over other analytical techniques such as LC-MS and GC-MS lies in the wider range of matrices that can be analyzed, including gases, liquids, solids and cross-linked polymeric materials (solvent-insoluble materials). With this analytical technique, for example, the smallest quantities of complex polymer samples (30 µg - 1 mg) such as plastics, coatings, rubber, resins, cellulose, etc. can often be analyzed directly without prior sample preparation. Py-GC-MS is used, for example, in materials science to determine the composition of polymers by providing information on monomers, copolymers and additives.
Pyrolysis is often preceded by additional thermodesorption (TD) to obtain further information. In the so-called "double-shot technique", volatile and semi-volatile compounds are released from a solid or liquid sample at a selected temperature in a first step, the thermodesorption, cryofocused with liquid nitrogen and then separated into the individual components by gas chromatography. TD/Py-GC/MS has the advantage that the (semi-)volatile compounds are selectively extracted from the main matrix at one (or more) specific temperature(s) by thermodesorption, which increases the sensitivity of their analysis.
Facts:
- Sample quantity: from 30 µg
Contact person: Dr. Tim Hammerschick
