Analysis of Terpenes in Cannabis Using the Agilent 7697A/7890B/5977B Headspace GC-MSD System

Significance of the Topic

Cannabis terpenes are key volatile compounds responsible for the distinct aroma and flavor of each strain. Their concentrations are influenced by genetics, harvest timing, drying, and storage, and they diminish over time. Rapid, accurate terpene profiling is essential for product characterization, quality control, and regulatory compliance in the burgeoning cannabis industry.

Objectives and Study Overview

This study presents an ultra-fast headspace GC method for simultaneous quantitation of 22 terpenes in Cannabis sativa flower and wax using the Agilent 7697A headspace sampler coupled to a 7890B GC with dual FID and MSD detection. The goal was to achieve full separation, reliable quantitation, and mass confirmation in under 6 minutes.

Methodology and Instrumentation

Sample preparation employs a full evaporation technique: 10–50 mg of ground, cold-kept cannabis material is sealed in a 10 mL headspace vial. Calibration standards (10–1 250 ppm) are prepared by spiking reference terpenes into vials. Headspace parameters (1 mL loop, 120 °C oven and loop temperatures, 10 min equilibration, 0.5 min injection) were optimized using Agilent’s method development tools. GC conditions include an initial oven hold at 60 °C, rapid ramp to 150 °C then to 250 °C, total cycle time 10 min. A 3:1 capillary splitter directs effluent to FID and MSD.

Used Instrumentation

• Agilent 7697A Headspace Sampler
• Agilent 7890B Gas Chromatograph with FID
• Agilent 5977B Mass Selective Detector (Residual Solvent Analyzer)
• Agilent VF-35 column (30 m × 0.25 mm × 0.25 µm)
• Split/splitless inlet with purged two-way splitter (3:1 FID:MSD)
• Standard headspace vials, Ultra Inert liners, septa

Main Results and Discussion

• All 22 terpenes eluted within 6 minutes with baseline resolution.
• Calibration curves (10–1 250 ppm) showed excellent linearity (R² ≥ 0.997 for FID, ≥ 0.998 for MSD).
• Limits of quantitation ranged from ~1.5 to 35 ppm; detection limits from ~0.45 to 10 ppm.
• Eight replicate injections at 50 ppm yielded RSD ≤ 1.1% (FID) and ≤ 2.6% (MSD).
• Analysis of a lemongrass tea challenge sample demonstrated the MSD’s ability to distinguish interfering species that would coelute and confound FID-only analysis.
• Total sample-to-sample cycle time of 10 minutes greatly enhances lab throughput.

Benefits and Practical Applications

• Reduces analysis time per sample from ~30 to < 6 minutes, increasing productivity nearly fourfold.
• Combines broad linear dynamic range of FID with selective mass spectral confirmation.
• Minimizes sample handling and preserves terpene profiles via headspace sampling.
• Ideal for quality control, strain profiling, potency testing, and compliance testing in cannabis laboratories.

Future Trends and Opportunities

Further improvements in headspace automation and advanced detector sensitivity will continue to shorten analysis time and enhance detection of minor terpenoids. Automated method optimization and data processing will simplify method development. Emerging multidimensional GC and high-resolution MS technologies may enable detailed characterization of isomeric terpenes and low-abundance compounds. Integration with process analytics could support real-time monitoring in commercial production.

Conclusion

The presented headspace GC-FID/MSD methodology delivers rapid, reproducible, and selective analysis of 22 key cannabis terpenes, meeting the demands of high-throughput laboratories for reliable aroma profiling and quality assurance.

References

1. Giese MW, et al. Development and Validation of a Reliable and Robust Method for the Analysis of Cannabinoids and Terpenes in Cannabis. Napro Research; 2015.
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3. Russo E. Taming THC: Potential Cannabis Synergy and Phytocannabinoid-Terpenoid Entourage Effects. British Journal of Pharmacology. 2011;163:1344.
4. Chemistry and Analysis of Phytocannabinoids and Other Cannabis Constituents. Humana Press; New Jersey.