Terpenes in Cannabis: Profile and Importance
Terpene profiling plays a crucial role in confirming the identity and medicinal effectiveness of different cannabis cultivars or strains. Terpenes, the primary organic components of cannabis resins and essential oils, contribute to the characteristic odor and organoleptic properties of cannabis. Composed of volatile and semivolatile C5 isoprene subunits, terpenes are believed to enhance the therapeutic effects of cannabinoids through the 'entourage effect', a phenomenon where various compounds work synergistically to intensify the overall medicinal benefits. As the type and concentration of terpenes vary between cannabis genetic lineages such as Cannabis sativa, Cannabis indica, and Cannabis ruderalis, the need for reliable analytical methods and standards is critical. These methods ensure accurate cultivar identification and provide scientific validation for the medicinal and pharmacological properties of cannabis strains.
Overview
LEGAL AND REGULATORY REQUIREMENTS FOR TERPENES TESTING IN CANNABIS
The increased use of cannabis as a recreational or medicinal drug has prompted stricter regulations for manufacturing practices and quality standards of cannabis-derived materials. This is especially important for testing terpenes, as concerns regarding therapeutic efficacy, safety, and quality have intensified. Cannabis quality control testing must be adhered to across different regions, including the United States and Canada, where the legalization landscape continues to evolve. These regulatory measures are necessary to ensure that cannabis products are safe for consumption and provide consistent therapeutic effects.
WORKFLOW FOR PROFILING OF CANNABIS TERPENES
The workflow for terpene analysis in cannabis, hemp, and their products generally follows several key steps: sample preparation (using solvent extraction or headspace-based solid-phase microextraction), preparation of standards and calibration, gas chromatographic separation, followed by mass spectrometric detection and data analysis. This comprehensive workflow ensures accurate terpene profiling and quantitation, which is essential for understanding the chemical composition of cannabis products.
CANNABIS TERPENES SAMPLE PREPARATION BY EXTRACTION OR HEADSPACE-SPME
Modern testing laboratories commonly use either solvent extraction or headspace-based solid-phase microextraction (HS-SPME) techniques to prepare cannabis samples for terpene analysis. Both methods are effective in preparing the sample for subsequent GC-FID or GC-MS analysis. HS-SPME provides several advantages, including:
- Minimizing co-extraction of non-volatile matrix components
- Increased sensitivity
- Simultaneous determination of terpenes and residual solvents from alcohol or hydrocarbon extraction
- Does not require special instrumentation and can be performed manually or using an autosampler
CALIBRATION STANDARDS FOR CANNABIS TERPENE QUANTITATION
Accurate terpene quantification in cannabis products requires authentic reference standards. Since many terpenes are isomers or enantiomers, it is important to use standards that specifically characterize the relevant isomer or enantiomer for correct identification and quantitation. Certified Reference Materials (CRMs), manufactured in accordance with ISO17034, offer verified accuracy, concentration, uncertainty, and traceability, making them ideal for quantitation. These CRMs are typically diluted into working standards and calibration curves to aid in accurate sample analysis.
GC-MS ANALYSIS OF TERPENES IN CANNABIS
GC-MS (Gas Chromatography-Mass Spectrometry) and GC-FID (Flame Ionization Detection) methods are widely used for terpene profiling and quantification in cannabis testing. GC-MS, in particular, offers excellent ionization under electron ionization (EI) conditions, providing both chromatographic resolution and sensitivity for terpene detection. The use of chiral GC columns helps address the challenges posed by terpene isomers and differences in their aromatic properties. GC x GC techniques, which provide additional resolution, are suitable for terpene profiling in complex cannabis matrices. Accurate and reliable terpene testing requires high-quality standards, reagents, chromatography consumables, and the correct choice of CRMs for method development, calibration, and quality control.