Fingerprinting the Terpene Profiles of Various Cannabis Strains using GC and GCxGC with High Performance TOFMS

Significance of the Topic

Cannabis contains a complex blend of terpenes that influence its aroma, therapeutic potential, and the so-called entourage effect. Reliable terpene profiling is critical for product standardization, quality control, and understanding interactions among cannabis constituents in medical and recreational applications.

Objectives and Study Overview

The primary goal was to implement a comprehensive two-dimensional gas chromatography (GCxGC) method paired with a high-performance time-of-flight mass spectrometer (TOFMS) to fingerprint terpene profiles across 23 commercial cannabis distillates. A comparative analysis with conventional GC-TOFMS evaluated improvements in separation, identification confidence, and data processing for strain characterization.

Methodology and Instrumentation

Sample Preparation and Injection:

• Distillates from 23 cannabis strains spiked with over 40 terpene standards.
• Dilution in isopropanol and transfer into 2 mL GC vials.
• Injection of 0.5 µL in split 250:1 mode at 250 °C.

Instrument Configuration:

• Gas Chromatograph: Agilent 7890 with LECO dual-stage quad-jet modulator and L-PAL 3 autosampler.
• Columns: Rxi-5 MS (30 m × 0.25 mm × 0.25 µm) for 1D and Rxi-17 Sil MS (0.6 m × 0.25 mm × 0.25 µm) for 2D.
• Temperature Program: 40 °C (1 min) to 325 °C at 10 °C/min, secondary oven +5 °C, modulation every 2 s at +15 °C.
• Mass Spectrometer: LECO Pegasus BT 4D, EI ionization, mass range 45–600 m/z, acquisition rates of 10 spectra/s (1D) and 200 spectra/s (2D).

Data Processing:

• Target Analyte Finding (TAF) workflow for rapid peak detection.
• Spectral similarity searches against large libraries, mass delta filters, and retention index confirmation.
• Statistical analyses including PCA and heat maps for terpene variability.

Main Results and Discussion

GCxGC-TOFMS achieved superior separation of coeluting sesquiterpenes (e.g., β-calacorene, dendrasaline) that were unresolved in 1D GC-TOFMS. Representative terpenes such as α-pinene, d-limonene, fenchone, and copaene were identified with high spectral similarity scores (>950/1000) and minimal mass deviations (<±0.03 Da). Two-dimensional contour plots generated distinct terpene “fingerprints” for indica, sativa, and hybrid samples. Multivariate analyses revealed no distinct clustering by strain type, suggesting overlapping terpene profiles among commercial products.

Benefits and Practical Applications

The integrated GCxGC-TOFMS approach enables rapid and confident identification of a wide array of cannabis volatiles. High chromatographic resolution allows detection of trace-level terpenes and minor analogues essential for aroma characterization, batch consistency verification, and regulatory compliance in QA/QC laboratories.

Future Trends and Opportunities

Advancements in sample preparation will aim to enhance extraction efficiency and broaden analyte coverage to include cannabinoids and flavonoids. Integration of automated data processing and machine learning models may facilitate real-time strain classification and predictive assessments of therapeutic effects. Expansion of spectral libraries will support discovery of novel cannabis metabolites.

Conclusion

This study underscores the value of GCxGC coupled with high-performance TOFMS for comprehensive terpene fingerprinting in cannabis. Enhanced chromatographic resolution, accurate mass measurements, and robust workflows deliver detailed chemical insights, advancing both research and quality assurance practices.

Reference

David E. Alonso, Julie Kowalski, Joseph E. Binkley. Fingerprinting the Terpene Profiles of Various Cannabis Strains using GC and GCxGC with High Performance TOFMS. LECO Corporation & Trace Analytics.