Aqueous Biphasic Systems Comprising Natural Organic Acid-Derived Ionic Liquids

Despite the progress achieved by aqueous biphasic systems (ABSs) comprising ionic liquids (ILs) in extracting valuable proteins, quest for bio-based and protein-friendly ILs continues. To address this need, work uses natural organic acids as precursors synthesis of four ILs, namely tetrabutylammonium formate ([N4444][HCOO]), acetate ([N4444][CH3COO]), tetrabutylphosphonium ([P4444][HCOO]), ([P4444][CH3COO]). It is shown that ABSs can be prepared using all acid-derived paired with salts potassium phosphate dibasic (K2HPO4) tripotassium citrate (C6H5K3O7). According to phase diagrams, [P4444]-based outperform their ammonium congeners ability undergo liquid–liquid demixing presence due lower hydrogen-bond acidity. However, deviations Hofmeister series were detected salts’ effect, which may related high charge density studied IL anions. As a proof concept extraction potential, these evaluated human transferrin, allowing efficiencies 100% recovery yields ranging between 86 100%. further disclose molecular-level mechanisms behind molecular docking studies performed. Overall, salting-out exerted salt main mechanism responsible complete transferrin toward IL-rich phase, whereas yield nature depend on specific “IL-transferrin” interactions.