Phase separation behavior modifying agents for aqueous two-phase separation within porous material

A device for isolating or concentrating one or more target analytes, the device comprising:

• i) a porous material;
• ii) components capable of forming a first phase solution and a second phase solution of an aqueous two-phase system (ATPS);
• and
• iii) one or more phase separation behavior modifying agents;
• wherein said components and said phase separation behavior modifying agents are embedded in said porous material, wherein when a solution containing said target analytes flows through said porous material, an aqueous two-phase system comprising said first phase solution and said second phase solution is generated, wherein the separation behavior of the two phase solutions is altered by said phase separation behavior modifying agents , and said target analytes are isolated or concentrated on said porous material, or
• wherein one or more of said components and said phase separation behavior modifying agents are embedded in said porous material, wherein the balance of said components and said phase separation behavior modifying agents are to be mixed with a solution containing said target analytes, thereby forming a mixed solution, wherein when said mixed solution flows through said porous material, an aqueous two-phase system comprising said first phase solution and said second phase solution is generated, wherein the separation behavior of the two phase solutions is altered by said phase separation behavior modifying agents, and said target analytes are isolated or concentrated on said porous material;
• wherein said one or more phase separation behavior modifying agents are present in varying amounts in different regions of the porous material;
• and
• wherein the phase separation behavior modifying agents are compounds which can induce, stabilize and/or promote phase separation of the ATPS by changing the temperature, pH, salt concentration, hydrophobicity/hydrophilicity, surface tension, and/or ionic strength of said components.