Optimization of ionic liquid-based ultrasound-assisted extraction to enhance cannabinoid recovery from hemp teas

The primary objective of this study was to investigate the ability of seven ionic liquids (ILs), NaBF4 salt, and five deep eutectic solvents (DESs) to extract five cannabinoids from hemp tea. Among the solvents examined, 1-butyl-3-methyl-imidazolium chloride (BMIMCl) proved to be a promising solvent for the recovery of cannabinoids, and it was selected for the subsequent optimization of ultrasound-assisted extraction (UAE) using response surface methodology (RSM). The optimized theoretical conditions were as follows: 0.071 M BMIMCl, a solvent-to-solid ratio of 24.15 mL/g of dried hemp tea material, and an extraction time of 20.80 min. These conditions resulted in theoretical extraction yields of 98.34 mu g/g for sample material for cannabichromene (CBC), 1104.69 mu g/g for cannabidiol (CBD), 209.64 mu g/g for Delta 9-tetrahydrocannabinol (Delta 9-THC), 40.43 mu g/g for cannabinol (CBN), and 55.49 mu g/g for cannabigerol (CBG). For comparison purposes, the optimized extraction parameters were applied to three more cannabis teas, originating from the Netherlands, Greece, and Italy. The analysis revealed varying levels of detected cannabinoids and exhibited levels of Delta 9-THC, ranging from 34.93 +/- 0.24 mu g/g to 199.46 +/- 1.02 mu g/g. Consequently, these findings have significant regulatory implications, as none of the examined hemp tea samples met the permitted zero tolerance threshold for Delta 9-THC.