Rapid determination of cannabinoids in edibles by thermal desorption GC/MS (1)

Importance of the Topic

The analysis of cannabinoids in edible products is crucial due to increasing global interest in cannabis-infused foods. Traditional solvent extraction from complex food matrices is laborious and time-consuming. The thermal desorption–GC/MS approach streamlines sample preparation, enabling rapid and accurate determination of THC, CBD, and CBN in various edibles.

Objectives and Study Overview

This technical note aims to demonstrate a direct thermal desorption method coupled with gas chromatography–mass spectrometry (TD-GC/MS) for quantifying cannabinoids in a cannabis-infused chocolate brownie. Key objectives include optimizing thermal desorption conditions and validating quantitation against product label claims using the standard addition method.

Methodology and Instrumentation

A Multi-Shot Pyrolyzer (Frontier Labs) was interfaced directly with a GC/MS system. Preliminary Evolved Gas Analysis (EGA) on a 100 ppm THC standard defined the optimal desorption temperature range (100–300 °C at 20 °C/min). Sample amounts (0.1–0.4 mg) of a commercial brownie were thermally desorbed (100–300 °C at 100 °C/min, 1 min hold) before GC separation on a UA-5+ column (30 m × 0.25 mm i.d., 0.25 µm film). MS detection scanned m/z 29–600 at 3 scans/s. A methanolic standard containing 100 ppm each of THC, CBD, and CBN was used for calibration via standard addition.

Main Results and Discussion

The TD-GC/MS chromatograms for brownie samples spiked with 0, 100, and 300 ng of the standard mixture showed distinct peaks for THC, CBD, and CBN. A calibration curve constructed from THC peak areas yielded a concentration of 0.996 mg/g in the brownie, matching the labeled 1 mg/g and demonstrating a reproducibility of 4.6 % RSD (n = 3).

Benefits and Practical Applications

• Elimination of solvent extraction simplifies workflow and reduces sample handling.
• Rapid throughput with minimal sample preparation enhances laboratory efficiency.
• Accurate quantitation supports regulatory compliance and quality control in the edibles market.

Future Trends and Potential Applications

Future developments may include automated TD-GC/MS sample introduction for higher throughput, expansion to other food-based bioactive compounds, and integration with machine-learning algorithms to improve compound identification and quantitation accuracy.

Conclusion

This study validates thermal desorption–GC/MS as a rapid, reliable technique for cannabinoid analysis in edibles, offering significant advantages over conventional extraction methods. The method demonstrated excellent agreement with product labeling and high reproducibility, making it suitable for routine quality control applications.