Determining Terpene Profiles of Cannabis Strains Using GC and GCxGC with High Performance TOFMS

Significance of the Topic

Cannabis contains a complex mixture of volatile and semi-volatile compounds, notably terpenes, which contribute to its aroma, flavor, and potential therapeutic effects through the so-called entourage effect. Accurate terpene profiling enables chemical classification of strains, quality control in cannabis products, and supports research into their medicinal properties.

Study Objectives and Overview

This application note presents an analytical approach for rapid and reproducible characterization of terpene profiles in 23 cannabis distillates using single-dimensional GC-TOFMS and comprehensive two-dimensional GC×GC-TOFMS. The primary objective was to compare the performance of GC and GC×GC methods in resolving and identifying a wide range of terpenes and related compounds across different strain types (indica, sativa, and hybrids).

Methodology and Instrumentation

Samples and over 40 terpene standards were diluted in isopropanol and injected (0.5 µL split 250:1) on a LECO GC×GC system equipped with Rxi-5 Sil MS and Rxi-17 Sil MS columns. A thermal modulator provided 2 s modulation, with primary oven from 40 °C to 325 °C at 10 °C/min. High-performance time-of-flight mass spectrometry (m/z 45–600) operated at 10 spectra/s for GC and 200 spectra/s for GC×GC. Automated NonTarget Deconvolution and spectral library searches (NIST 17, Wiley 11) facilitated compound identification.

Used Instrumentation

• LECO Pegasus BT 4D GC×GC Quad Jet Thermal Modulator
• L-PAL 3 Autosampler
• Rxi-5 Sil MS (30 m × 0.25 mm × 0.25 µm) and Rxi-17 Sil MS (0.6 m × 0.25 mm × 0.25 µm) columns
• LECO Pegasus BT 4D TOFMS, EI ionization, 45–600 m/z

Main Results and Discussion

GC×GC-TOFMS achieved a more than fourfold increase in detected peaks and over 50% more terpene identifications compared to single-dimensional GC-TOFMS. Coeluted sesquiterpenes (e.g., dendrasaline and β-calacorene) were resolved in the second dimension, yielding cleaner spectra and higher library match scores (average similarity 869/1000 for GC×GC vs. 548/1000 for GC). Profiling revealed additional classes such as alkanes, aldehydes, esters, and polyaromatics, with average spectral similarities above 900/1000.

Benefits and Practical Applications

• Enhanced chromatographic resolution and improved spectral quality accelerate terpene fingerprinting of cannabis.
• Automated deconvolution and large-scale library searching provide confident compound identification.
• Comprehensive profiles support strain differentiation, quality assurance, and research into aroma and therapeutic effects.

Future Trends and Applications

Further studies may explore alternative extraction techniques to broaden compound coverage, integrate cannabinoids and lipid-soluble metabolites, and apply multivariate statistics for more robust strain classification. Advances in faster modulation, higher mass resolution, and machine-learning algorithms could further enhance chemical fingerprinting and predictive modeling of biological activity.

Conclusion

The Pegasus BT 4D GC×GC-TOFMS platform enables fast, reproducible, and detailed terpene profiling in cannabis distillates. Two-dimensional separation significantly increases compound detection and identification confidence, although product labeling did not correlate with terpene composition in statistical clustering. This approach lays the groundwork for a shift from cultivar names to chemistry-based classification in cannabis quality control and research.

References

• NIST 17 Mass Spectral Library
• Wiley 11 Mass Spectral Library