A new study found that a solventless electrostatic separation technique more than doubled the THC potency of selected cannabis kief fractions while cutting plant stalks and other impurities in half.
The research, published in the September issue of the Journal of Applied Research on Medicinal and Aromatic Plants, examined a technique known as tribo-electrostatic separation, or T-ES, for separating cannabinoid-rich glandular trichomes from other plant material.
Researchers designed and built a food-safe separator that uses friction to electrically charge particles in kief before passing them through an electric field. Different components are then drawn toward different electrodes, allowing trichome-rich material to be separated from stalks and other impurities.
The starting kief contained 228.5 milligrams of total THC per gram. After one separation cycle, THC concentration in material collected from the positive side increased to 349.7 mg/g, a 53% increase.
After a second cycle, it reached 434.3 mg/g, up 90.1%. Following three cycles, the selected fraction reached 492 mg/g, representing a 115.3% increase from the original material.
Researchers also found that visible stalks and other impurities declined by 50% after three separation cycles.
The opposite effect occurred in material collected on the negative side of the device, where total THC progressively declined to 95.1 mg/g after three cycles. Researchers said the findings indicate the technique was successfully sorting cannabinoid-rich glandular trichome heads from less potent plant material.
The process also increased concentrations of other cannabinoids, including CBGA and CBCA, in the enriched fractions.
Researchers said electrostatic separation could offer a solventless method for improving the quality and potency of kief and other cannabis postharvest products. They noted that although electrostatic equipment is already marketed for cannabis processing, its effectiveness has received relatively little rigorous scientific evaluation.
The study was conducted by researchers including scientists affiliated with McGill University and the University of Ottawa. Funding came from the Natural Sciences and Engineering Research Council of Canada in partnership with cannabis producer EXKA Inc.
The researchers said additional work is warranted to optimize the technology for broader industry applications.
