A novel temperature-responsive biphasic deep eutectic solvent-based solvent system: Integrated efficient extraction, enrichment and recovery of phytochemicals

The current large-scale use of organic and some toxic reagents hinders the development of plant secondary metabolite extraction and processing industry. Here, a biphasic temperature-responsive solvent system consisting of hydrophilic deep eutectic solvent (choline chloride: levulinic acid) and fatty acid-based hydrophobic deep eutectic solvent is developed. Some characteristics of this intelligent solvent system, including hundreds of synthesis ratios and corresponding switching temperatures, phase ratios, etc., have been comprehensively determined. Subsequently, it is applied to different plant matrices. The extraction efficiencies ranged from 1.006 to 6.807 times higher than those of conventional organic reagents, with separation efficiencies ranging from 60.7 % to 100 %, besides the fact that the hydrophilic components are almost entirely distributed in the lower phase. The recovery of targeted phytochemicals achieves satisfactory results during the simultaneous extraction and enrichment process. Mechanisms of switching, extraction, and enrichment have been elucidated to a certain extent from the point of view of chemical computational simulations. Overall, this new green solvent system is universal and can be applied to a wide range of phytochemicals extraction and separation from plants in a one-pot operating unit. Also, it is almost the greenest of the temperature-responsive solvents studied so far and has superior application prospects.