Cannabinoids Analysis in Cannabis and Hemp Using HPLC and GC Techniques
Cannabinoid analysis involves testing cannabis and hemp for the presence of active compounds like THC and CBD using techniques like High-Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC).
Overview
Types of Cannabinoids
Cannabinoids are a group of C21 terpenophenolic compounds found mainly in *Cannabis indica*, *Cannabis sativa*, and *Cannabis ruderalis*. They interact with cannabinoid receptors in the body, leading to psychoactive and non-psychoactive effects. There are 11 main subclasses of cannabinoids, including CBG-type (cannabigerol), Δ9-THC-type (tetrahydrocannabinol), CBD-type (cannabidiol), CBC-type (cannabichromene), CBN-type (cannabinol), and others. Cultivars are often bred to enhance THC or CBD production. The pharmacological effects of many cannabinoids are still being researched.
Workflow for Cannabinoid Analysis
Analyzing cannabis products presents challenges due to the variety of cannabinoids, terpenes, and matrix types (e.g., flowers, extracts, edibles). A typical analysis workflow includes: sample preparation (using extraction methods such as QuEChERS or SPE), calibration with high-quality reference standards, and chromatographic separation and analysis via Liquid Chromatography (LC) or Gas Chromatography (GC). This workflow is crucial for accurate and reliable cannabis testing.
Cannabis Sample Preparation
Cannabis samples come in many forms, such as dried flowers, extracts, cosmetics, and edibles. The cannabis plant is complex, containing cannabinoids, terpenes, lipids, chlorophyll, and more. Extraction methods such as solvent-based extraction, QuEChERS, and Solid-Phase Extraction (SPE) are commonly used to isolate cannabinoids from the plant matrix, preparing samples for further analysis.
Standards and Calibration
Accurate quantification of cannabinoids requires precise calibration using reference standards. Cannabinoid standards are typically resinous and air-sensitive, often provided in solution form. Certified Reference Materials (CRMs) are used to ensure accuracy and traceability. System suitability standards are critical for ensuring proper method control, especially when analyzing regulated products like hemp, where total THC levels must remain below legal limits.
HPLC Analysis of Cannabinoids
High-Performance Liquid Chromatography (HPLC) is the primary method for cannabis potency analysis. HPLC systems equipped with UV or Mass Spectrometry (MS) detectors provide high-resolution separations of cannabinoids, often in under 10 minutes. UV detection is cost-effective, while MS offers specificity for profiling and quantifying cannabinoids by measuring their mass-to-charge (m/z) ratio. Isotopically labeled internal standards are essential for accurate quantification in MS-based methods.
GC Analysis of Cannabinoids
Gas Chromatography (GC) with Flame Ionization Detection (FID) or Mass Spectrometry (MS) is another key method used in cannabis testing. GC separates cannabinoids using a low-polarity stationary phase and high temperatures that cause decarboxylation of acidic cannabinoids like THCA and CBDA. Derivatization may be needed to separately analyze acidic and neutral cannabinoids. This method allows for accurate determination of both forms in a cannabis sample.