Fully Automated Sample Preparation for the Analysis of Terpenes in Cannabis Flower

Importance of the Topic

Terpenes are key contributors to the distinctive aroma and flavor profiles of cannabis strains. Accurate terpene profiling supports product quality control, regulatory compliance, and consumer safety. Traditional manual sample preparation for GC/MS analysis can be laborious, error-prone, and resource-intensive, driving the need for an automated, high-throughput workflow.

Study Objectives and Overview

This work demonstrates a fully automated sample preparation protocol for terpene analysis in cannabis flower using the Agilent PAL3 Series II RTC robotic sampler coupled to an Agilent Intuvo 9000 GC with a 5977C mass spectrometer. The objectives were to evaluate accuracy, precision, and efficiency gains from automation while reducing solvent and sample usage.

Methodology

• Chemicals and Standards: Two terpene standard mixes (CAN-TERP-MIX1H and MIX2H) containing 21 terpenes, internal standard 2-fluorobiphenyl in ethyl acetate, and hemp seed oil as blank matrix.
• Automated Preparation: PAL Method Composer scripted eight calibration levels (3.83 to 490.2 µg/mL) and sample extractions from homogenized cannabis flower samples.
• GC/MS Parameters: 1.0 µL split injection (150:1); oven program from 75 °C (1 min) to 165 °C at 5 °C/min, then to 250 °C at 175 °C/min (10.5 min hold); carrier flow 2.0–2.2 mL/min; MS in SIM mode with source 300 °C, transfer line 260 °C, quadrupole 200 °C, and 13 min solvent delay.

Used Instrumentation

• Agilent PAL3 Series II RTC sampler with liquid handling tools, vortex mixer, and wash modules.
• Agilent Intuvo 9000 GC equipped with dual Agilent J&W DB-Select 624 columns and split/splitless injector.
• Agilent 5977C mass selective detector operated in selected ion monitoring mode.

Main Results and Discussion

• Calibration Linearity: Eight-point calibration curves showed R² > 0.99 using quadratic fits with 1/x weighting.
• Accuracy and Precision: Across low (3.83 µg/mL), mid (30.64 µg/mL), and high (245.10 µg/mL) levels, accuracy ranged 91.5 %–118.6 % and precision (%RSD) remained below 8.7 %.
• Detection Limits: LOD and LOQ were below the lowest calibration level, setting a practical reporting limit at 3.83 µg/mL.
• Sample Analysis: Six cannabis flower samples exhibited unique terpene profiles. Quadruplicate extractions demonstrated high precision, with %RSD between 0.7 % and 10.2 % for major terpenes.

Benefits and Practical Applications

• Minimized human error and variability through automated sample handling.
• Reduced consumption of solvents and sample material, lowering costs and environmental impact.
• Enhanced throughput supports quality assurance, product development, and regulatory testing in cannabis laboratories.

Future Trends and Opportunities

• Expansion of automation to broader volatile and semi-volatile analyte classes in cannabis and other botanicals.
• Integration with high-resolution mass spectrometry and advanced library matching for comprehensive profiling.
• Development of miniaturized, on-line extraction techniques for faster turnaround times.
• Application of data analytics and machine learning to correlate terpene patterns with strain characteristics and consumer effects.

Conclusion

The Agilent PAL3 Series II RTC sampler combined with the Intuvo 9000/5977C GC/MS provides a reliable, precise, and eco-friendly solution for automated terpene analysis in cannabis flower. This workflow improves laboratory efficiency and data quality while supporting sustainable practices in high-throughput environments.

References

• Hollis J. S.; Harper T.; Macherone A. Terpenes Analysis in Cannabis Products by Liquid Injection using the Agilent Intuvo 9000/5977B GC/MS System. Agilent Technologies Application Note 5994-2032EN.