How Labs Measure 93 Cannabis Terpenes at Once

Last updated on September 27, 2026 · Originally published May 10, 2021

A cannabis terpene profile is not simply waiting inside the flower for a laboratory to read it. The result also depends on which part of the plant was sampled, how the flower was stored and, crucially, how the laboratory prepared it.

Terpenes are volatile. Grinding, heating, extracting or concentrating a sample can make some disappear faster than others, changing the profile before the instrument even measures it.

In 2019, researchers at the Technion developed a method designed to reduce that problem. It combined static headspace sampling, gas chromatography and tandem mass spectrometry to quantify 93 terpenes and terpenoids in cannabis flower and extracts.[2]

The machinery sounds forbidding. The basic idea is not: collect the volatile compounds without injecting the plant itself, separate them, and then identify each one through a highly selective series of measurements.

Why Cannabis Terpenes Are Difficult to Measure

Cannabis contains far more volatile compounds than the handful normally printed on a certificate of analysis — a reflection of how labs test for terpenes as much as of the plant itself. Many occur at low concentrations, several have nearly identical structures, and their abundance changes with genetics, flower position, maturity, drying and storage.

The analytical method adds another source of variation.

A 2018 study demonstrated that solvent choice and sample preparation changed the composition recovered from cannabis flower.[1] Rotary evaporation and speed-vac drying reduced monoterpenes to almost undetectable levels and cut the measured amount of many sesquiterpenes roughly in half. A gentle nitrogen stream caused less damage.

In other words, a laboratory can alter the terpene profile while trying to measure it.

That is the problem headspace analysis is intended to reduce.

Step One: Sample the Vapour, Not the Plant

In static headspace sampling, a small amount of ground cannabis is sealed inside a vial and heated. The terpenes enter the gas above the sample — the “headspace” — and an autosampler transfers some of that vapour into the gas chromatograph.

The 2019 method heated the vial to 140°C for 40 minutes. It used a full evaporation technique, meaning the sample was small enough and the conditions strong enough to drive the target volatile compounds into the headspace rather than leaving them divided unpredictably between the plant material and the vapour.[2]

This matters because ordinary headspace measurements can be affected by the sample matrix.[5] A terpene may move into the vapour differently in ground flower than it does in a clean calibration solution. Full evaporation is intended to reduce that difference.

It also keeps most non-volatile plant material out of the instrument. Waxes, pigments and other heavy compounds remain in the vial, producing a cleaner chromatogram and reducing contamination of the GC column and mass spectrometer.

The flower still has to be ground, but it does not require conventional solvent extraction, filtration or evaporation before analysis.

Step Two: Separate the Compounds

The vapour enters the gas chromatograph and is carried by helium through a long, narrow column coated with a semipolar stationary phase.

Different compounds travel through that column at different speeds. More volatile monoterpenes generally emerge before the larger sesquiterpenes, but boiling point is not the only factor. Molecular structure, polarity and interaction with the column also affect how long each compound is retained.

The time at which a compound leaves the column — its retention time — provides the first clue to its identity.

Separation is essential because cannabis contains many closely related compounds. If two terpenes leave the column together, the detector may struggle to distinguish them, however sophisticated it is.

Step Three: Identify Them Twice

After leaving the GC column, the compounds enter a triple-quadrupole tandem mass spectrometer.

Electron impact breaks each molecule into charged fragments. The first quadrupole selects a characteristic ion associated with the compound being measured. A collision cell then fragments that ion again, and the third quadrupole looks for specific resulting fragments.

This gives the method two stages of mass selection. It is a little like asking for two matching pieces of identification rather than one.

That extra selectivity matters in cannabis. Many terpenes are isomers, meaning they share the same molecular formula and may produce very similar mass spectra. Retention time combined with characteristic fragment transitions gives the laboratory greater confidence than either measurement could provide alone.

Reference standards establish where each compound should appear and how strongly the instrument responds at known concentrations. Calibration curves can then be used to calculate how much is present in the cannabis sample.

What the Researchers Found

The researchers validated the method for 93 terpenes and terpenoids, reporting acceptable accuracy, sensitivity, repeatability and reproducibility.[2]

They then applied it to 16 medical cannabis chemovars. Most chemovars produced relatively distinctive patterns among their more abundant terpenoids, even when samples were obtained on different dates. Absolute concentrations could change with ageing, but much of the broader chemical pattern remained recognisable.

The team also compared untreated flower with samples subjected to extraction, evaporation or decarboxylation. Those preparation steps altered the measured profile, with volatile monoterpenes particularly vulnerable.

That is the method’s central advantage. Static headspace analysis does not merely avoid dirtying the instrument. It can produce a profile that is closer to the composition of the untreated flower than methods requiring extensive preparation.

That does not make the measurement perfectly neutral. The flower is still ground and heated, and the sampling location, storage history and analytical conditions still matter.

The Heat Creates Its Own Problem

Heating a cannabis sample to 140°C may seem like a strange way to preserve its original terpene profile. Later research shows why the temperature and exposure time must themselves be validated.

In 2026, Hundertmark and colleagues developed a full-evaporation headspace GC/MS method for 45 cannabis terpenes.[4] Their optimisation produced gentler conditions: 100°C for 20 minutes.

The researchers identified thermal degradation as an important limitation. At higher temperatures, some terpenes began breaking down after reaching their maximum analytical response. Because terpenes can also transform into other terpenes or oxidation products, excessive heating could quietly distort the profile rather than simply reduce every result equally.

The later finding does not by itself invalidate the earlier 93-compound method. The studies used different instruments, analyte panels and validation procedures. It does show that headspace analysis is not inherently free of artefacts. A laboratory must demonstrate that its chosen combination of sample size, temperature and heating time releases the target compounds without substantially transforming them.

Ninety-Three Compounds or Ten?

A separate 2019 study from the University of Mississippi took a narrower approach.[3] Its GC/MS method used ethyl acetate extraction and targeted ten major cannabis terpenes, including α-pinene, β-myrcene, limonene, linalool and β-caryophyllene.

The contrast is useful.

A focused panel is simpler and may be entirely adequate for routine testing when a laboratory only needs to report the dominant terpenes. A 93-compound method provides a much deeper chemical fingerprint, making it more useful for research, chemovar comparison and the study of less abundant compounds.

Neither approach is automatically more correct. The appropriate method depends on the question being asked.

Breadth also has a cost. Closely related terpenes must be separated carefully, standards must be available for every reported compound, and the wider method takes longer to run and validate.

What a Terpene Result Really Means

The larger lesson is that a terpene result is a measurement, not an intrinsic number that every laboratory will necessarily reproduce.

The flower contributes its chemistry. Sampling, grinding, storage, extraction, heating, chromatography and detector settings all influence what finally appears on the report.

The 93-terpenoid method showed that unusually broad cannabis profiling is possible without conventional solvent extraction. The later work adds an important caution: even a method designed to avoid sample-preparation losses must prove that its own heating step does not create a different profile.

That is why labs must validate their approach to cannabis testing for the products and compounds they intend to measure. The number of terpenes on the panel matters. How reliably the method separates, identifies and quantifies them matters more.

References

Namdar D, Mazuz M, Ion A, Koltai H. Variation in the compositions of cannabinoid and terpenoids in Cannabis sativa derived from inflorescence position along the stem and extraction methods. Industrial Crops and Products. 2018;113:376–382. doi:10.1016/j.indcrop.2018.01.060
Shapira A, Berman P, Futoran K, Guberman O, Meiri D. Tandem Mass Spectrometric Quantification of 93 Terpenoids in Cannabis Using Static Headspace Injections. Analytical Chemistry. 2019;91(17):11425-11432. doi:10.1021/acs.analchem.9b02844
Ibrahim EA, Wang M, Radwan MM, et al. Analysis of Terpenes in Cannabis sativa L. Using GC/MS: Method Development, Validation, and Application. Planta Medica. 2019;85(5):431-438. doi:10.1055/a-0828-8387
Hundertmark M, Germerott T, Wunder C. HS-FET-GC/MS-method development and validation for analysis of 45 terpenes—creating a complementary tool for comprehensive profiling of cannabis flowers in forensics. Drug Testing and Analysis. 2026;18(1):118–138. doi:10.1002/dta.3966
Kolb B, Ettre LS. Static Headspace-Gas Chromatography: Theory and Practice. 2nd ed. Hoboken, NJ: Wiley; 2006.