Effect of multi-cycle tribo-electrostatic separation on cannabinoid content in dry-sifted cannabis extracts

Abstract

Cannabis sativa is recognized for its diverse uses in both medicinal and recreational contexts, garnering increasing attention in recent years due to shifting global legislature. This study investigated the potential of tribo-electrostatic separation (T-ES) technology as a solventless alternative to traditional extraction techniques for separating cannabis glandular trichomes and enriching kief byproduct. A food-safe, T-ES device was designed and fabricated to leverage electrostatic forces for effective screening of trichome structures by subjecting kief to a series of T-ES cycles. Morphological changes in trichome structure were observed and quantified through scanning electron microscopy (SEM), followed by cannabinoid analysis with high-performance liquid chromatography-ultraviolet. Data relay marked T-ES separation, where the number of stalks and impurities in the raw kief samples significantly (p < 0.05) decreased after multiple T-ES cycles for kief collected from the positive bin. By the third T-ES cycle, the quantity of stalks and impurities was reduced by 50%, and a linear relationship (R² of 0.98) was observed. Quantitative evaluation revealed consistent changes in cannabinoid concentrations, whereby potency (total THC) rose from initial levels by 53%, 90%, and 115% in kief samples collected after each T-ES cycle on the positive electrode side. In contrast, cannabinoid potency decreased by 30%, 41%, and 59% through the cycles in the negative side, suggesting T-ES is an effective method to improve the quality of cannabis extracts. Findings illustrate T-ES’s capability in improving cannabis postharvest processing by reporting cannabinoid potency improvement with selective trichome screening, setting a stage for future studies aimed at optimizing T-ES technology for broader industry applications.