SPME Arrow Sampling of Terpenes in Cannabis Plant Material

Importance of the Topic

The profile of volatile terpenes in cannabis has become a critical quality attribute as medicinal and recreational use expands globally. Reliable, rapid, and cost-effective analytical methods support regulatory compliance, product standardization, and strain differentiation based on aroma and flavor profiles.

Objectives and Study Overview

This work demonstrates a headspace solid-phase microextraction (SPME) Arrow approach coupled with gas chromatography–mass spectrometry (GC-MS) for both qualitative profiling and quantitative determination of terpenes in homogenized cannabis flower samples. The goals were to streamline sample preparation, avoid solvent artifacts, and achieve high sensitivity and reproducibility across multiple plant varieties.

Methodology and Instrumentation

Sample Preparation and Extraction

• Qualitative profiling: 20 mL headspace vials containing 20–30 mg homogenized plant material; 120 µm DVB/CAR/WR/PDMS SPME Arrow; 10 min equilibration; static headspace sampling.
• Quantitative analysis: 100 mg sample, addition of 10 µL calibration standard (2–50 ppm), 8 mL water; 100 µm PDMS SPME Arrow; 5 min incubation at 40 °C with 1 000 rpm agitation; 5 min extraction, 3 min desorption, 5 min conditioning at 270 °C.

Used Instrumentation

• SPME sampler: PAL RTC rail system with PAL SPME Arrows.
• Gas chromatograph: Agilent 7890B GC with inert inlet liner (2 mm id) and J&W DB-1ms column (60 m × 0.25 mm, 0.25 µm).
• Mass spectrometer: Agilent 5977B MSD (High Efficiency Source), scan mode, transfer line 300 °C.

Chromatographic Conditions

• Oven program: 60 °C (2 min) → 5 °C/min to 140 °C (1 min) → 15 °C/min to 250 °C (4 min).
• Inlet: 270 °C, split 100:1, constant flow 1 mL/min.

Main Results and Discussion

Qualitative profiling across six flower samples using the 120 µm Arrow revealed distinct terpene fingerprints with well-resolved peaks in the 8–30 min retention window. Quantitative calibration (2–50 ppm) for 20+ terpenes showed excellent linearity (R2 > 0.995). Representative analytes such as α-pinene, β-pinene, limonene, myrcene, and humulene exhibited calibration slopes consistent across injections. GC-MS chromatograms confirmed reproducible responses and clear separation of structural isomers.

Concentration data highlighted strain-dependent variations: some samples were enriched in monoterpenes (e.g., α-pinene up to 260 ng/mL), while others showed higher sesquiterpene content (e.g., caryophyllene oxide > 140 ng/mL). The addition of water and controlled agitation improved extraction consistency.

Benefits and Practical Applications

• Solvent-free extraction eliminates co-extracted interferences and reduces system contamination.
• High sensitivity and robustness enable detection of low-abundance terpenes without overload.
• Rapid sample throughput supports routine quality control in cannabis testing laboratories.
• Spectral data from MS enhances compound confirmation and purity assessment compared to flame ionization detection.

Future Trends and Potential Applications

Integration of automated SPME Arrow workflows with enhanced MS detectors may further shorten analysis time and lower detection limits. Expanding the method to edibles, concentrates, and other botanical matrices will broaden its utility. Data-driven profiling could support chemovar classification, process monitoring, and traceability in supply chains.

Conclusion

This study validates headspace SPME Arrow GC-MS as an efficient, accurate, and reproducible approach for terpene profiling in cannabis plant material. The method’s solvent-free design, combined with strong linearity and sensitivity, makes it well suited for both research and routine quality control laboratories.

References

1. Agilent Technologies Application Note 5991-8499EN. Analysis of Terpenes in Cannabis Using the Agilent 7697A/7890B/5977B Headspace GC-MS System, September 2017.
2. Stenerson K.; Halpenny M. Analysis of Terpenes in Cannabis Using Headspace Solid-Phase Microextraction and GC–MS, LCGC, May 2019.