Removing synthetic and pernicious materials from industrial effluents to prevent their discharging into the environment, recovering valuable compounds in food residues to prevent their wasting, and quantifying target species in complex matrices are among the significant reasons that necessitate developing effective extraction/separation methods. This work addresses the liquid-liquid extraction performance of aqueous biphasic systems (ABSs) constructed by polypropylene glycol (PPG) and tetraalkylammonium salts. The thermodynamic functions of phase separation and the parameters affecting the PPG-tetraalkylammonium salt ABS formation were scrutinized. The partition coefficient and extraction efficiency of two alkaloids (caffeine and codeine), a flavoring antioxidant (vanillin), a bioactive pigment (curcumin), and three textile dyes (methylene blue, rhodamine B, and sudan III) were examined in the studied ABSs. Caffeine, vanillin, curcumin, rhodamine, and sudan preferentially concentrated in the polymer-rich phas
