Investigations on gas-induced phase split, i.e., salting out by a nearcritical gas, were carried out for several aqueous solutions (including an ionic liquid). The research aimed to verify and characterize high-pressure multiphase equilibria that might be suitable for technical applications. The respective criteria are occurrence at relatively low pressures and the existence of the phase equilibrium phenomenon over a significant region of both composition and pressure, which is related to a pressure-induced significant alteration of the compositions of the coexisting liquid phases. The employed ionic liquids revealed the expected phase behavior but without full compliance of all criteria. In anticipation of an application, the partitioning of an amphiprotic, high-molecular biomolecule to the coexisting liquid phases was successfully administered via a pH variation.