Study Shows Py-GC-MS Outperforms Traditional GC-MS for THC Edible Forensics

Edible cannabinoid products have been in high demand for the past century due to ease of use, discretion, and the induced, long lasting psychoactive effects generated. The monitoring and analyzing of edibles containingdelta-9-tetrahydrocannabinol (THC), therefore, is critical. Research conducted by Dubai Police’s General Department of Forensic Science and Criminology (United Arab Emirates) involved the qualitative analysis of THC edibles using pyrolysis coupled with gas chromatography-mass spectrometry (GC-MS) as an application to compare its sensitivity and effectiveness to other traditional techniques such as standalone GC-MS, by analyzing seven different edible cannabinoids that were collected from Dubai Police Forensic Laboratories from the years 2017-2022. A paper based on this research was published in Science & Justice (1).

While the consuming of cannabis started with smoking the plant in 1920’s, oral consumption ingestion of edibles containing THC became popular in the 1960’s (2,3). In many countries, THC products are accessible in legal stores; this process has increased in the past decade by 20%, as has as the popularity of THC-infused edibles, which are sold in a variety of forms (including gum, cookies, drinks, and chocolates) with varying degrees of concentrations of the active component (2-4).

Pyrolysis has been widely used over the last two to three decades as an analytical technique where large molecules are degraded into smaller volatile species using only thermal energy. The goal of researchers applying analytical pyrolysis is to use the chromatographic information of pyrolysis products to uncover the makeup or structure of the original sample (5). “The complexity of polymeric materials can vary extensively, and they can be very challenging to analyze,” the authors of the paper wrote. “Pyrolysis, combined with modern analytical methods, such as GC and/or MS, has become a quick, convenient and powerful tool for characterizing polymers in volatile, complex heterogeneous samples.” (1)

The results of their study indicated that Py-GC-MS proved to be a reliable technique for the analysis of edible cannabinoids, as a linear regression was obtained between concentration and abundance with R² = 0.99. Additionally, it was found that matrix effect was significantly reduced in comparison to GC-MS analysis. Furthermore, sample preparation time and the use of chemical reagents were reduced, which saved both time, cost, and, perhaps most importantly, limited human error impact on the analysis (1).

“The need for easier, and faster analysis technique for the analysis of THC edible products,” the authors wrote, “is pressing as the production and consumption of these products is expanding globally. The rapid detection of THC in edibles will prove extremely useful in forensic laboratories operating in countries where THC is punishable by law. Various analysis techniques showed reliable and sensitive options for the detection of THC despite matrix effect.” (1)

The authors note that their study is the first to examine the performance of GC/MS vs Py-GC-MS for the analysis of cannabinoids in edibles, stating that “the utilization of pyrolysis coupled with GC-MS provided a promising analytical technique that achieves high sensitivity, less chemical use, and most importantly no sample preparation, making it a cost-effective method with less chance of human error.” (1)

They also note that countries which have legalized the production of THC edibles are concerned with the concentration of THC in the products. Therefore, further work needs to be done to investigate the reliability of Py-GC-MS for quantitation of THC in cannabinoids consumables (1).

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References

1. Almadani, F.; Gewily, S.; Lanjawi, A. et al. Direct Analysis of THC Containing Edibles Using Py-GC/MS. Sci. Justice 2025, 65 (6), 101346. DOI: 10.1016/j.scijus.2025.101346
2. Legalised Cannabis: A Rarity Around the World. The Times of India website. 2021. https://timesofindia.indiatimes.com/world/europe/legalised-cannabis-a-rarity-around-the-world/articleshow/87907640.cms (accessed 2022-03-24)
3. Barrus, D. G.; Capogrossi, K. L.; Cates, S. C. et al. Tasty THC: Promises and Challenges of Cannabis Edibles. Methods Rep RTI Press; 2016. DOI: 10.3768/rtipress.2016.op.0035.1611
4. W. Yakowicz, W. Where is Cannabis Legal? A Guide to All 50 States. Forbes website. 2023https://www.forbes.com/sites/willyakowicz/2023/01/06/where-is-cannabis-legal-a-guide-to-all-50-states/?sh=502d42f61619 (accessed 2023-02-10)
5. Arrieta, M.; Parres, F.; López, J. et al. Development of a Novel Pyrolysis-Gas Chromatography/Mass Spectrometry Method for the Analysis of Poly(lactic Acid) Thermal Degradation Products. J. Anal. Appl. Pyrol. 2013,101, 150-155. DOI: 10.1016/j.jaap.2013.01.017