oa Direct Analysis of Source Rocks in PY-GC-MS: Considerations for the Evaluation of Volatilized Molecules and Pyrolysis Products

The present study evaluated the direct sample introduction (DSI) method in pyrolysis GC-MS for analyzing petroleum source rocks. By bypassing traditional solvent extraction, this approach rapidly screens thermally extractable organic matter and preserves volatile compounds. The work systematically examined how system parameters such as furnace temperature, rock sample mass, particle size, and inorganic matrix effects influenced the release of volatilized and pyrolysis-generated molecules. Statistical analyses (HCA and MANOVA) revealed that particle size significantly affected thermal desorption kinetics and reproducibility, while temperature changes controled the balance between volatilization and pyrolysis. Notably, hydrocarbon expulsion peaked at around 400°C before decreasing due to cracking into lighter gaseous compounds. Overall, the (DSI)Py-GC-MS technique proved to be a powerful tool for assessing source rock organic content and establishing oil–source rock correlations. Careful control of experimental conditions is essential for accurate molecular profiling, and further research is needed to differentiate the contributions of various physical and chemical processes happening in the pyrolyzer system.