Methods and systems for the extraction of a formation fluid sample using a fluid extraction tool including an elongated body and a sealing pad extending therefrom, the sealing pad having an opening for establishing fluidic communication between an earth formation and the elongated body. The sealing pad communicable with from a container holding a selective permeability agent (SPA) capable of modifying the permeability of one or more fluids within the formation. The container coupled with a device for injecting the SPA into the earth formation and extracting a formation fluid sample therefrom.