Residual Solvent Analysis in Cannabis and Hemp by GC

Introduction

Residual solvent testing is an essential step in ensuring the safety and quality of cannabis and hemp products. During extraction, solvents such as ethanol, butane, and propane are often used to separate active compounds from the plant material. If not fully removed, these solvents can remain in the final product and pose health risks to consumers.

Testing for residual solvents helps producers demonstrate compliance with safety regulations and confirm that their products are free from harmful chemical residues. Reliable analysis also supports good manufacturing practice and protects consumers who depend on these products for medical use.

The Challenge

Extraction solvents can remain in the final product

Many cannabis extraction processes use hydrocarbon gases or organic solvents to separate cannabinoids and terpenes from plant material. While effective, these solvents can persist in concentrates, edibles, or vapour products if not properly purged.

Residual solvents can have harmful effects if inhaled or ingested. For example, ethanol residues can cause irritation or toxicity in sensitive users, and high levels of butane or propane pose additional health and safety risks.

The level of acceptable solvent residue varies across regions, and not all producers are required to perform routine solvent testing. This makes it vital for manufacturers and testing labs to use an analytical method that can detect multiple volatile compounds at trace levels with accuracy and confidence.

The Solution

Gas chromatography detects residual solvents quickly and effectively

Gas chromatography (GC) is a well-established technique for measuring volatile compounds, making it ideal for residual solvent testing. Using a Flame Ionisation Detector (FID) and a headspace autosampler, the Ellutia 200 Series GC provides accurate and efficient analysis of solvents commonly used in cannabis extraction.

Headspace sampling isolates volatile components from the liquid or solid sample without direct injection. The sample is heated in a sealed vial, allowing solvents to evaporate into the gas phase. This vapour is then injected into the GC for precise quantification, reducing matrix interference and extending instrument life.

The combination of the 200 Series GC-FID and an EL2000H or EL2100H headspace autosampler offers a compact, reliable setup for routine solvent testing in cannabis and hemp laboratories.

If you’d like an overview of how GC fits into cannabis testing workflows, take a look at the Cannabis Testing Buyers Guide.