Methods and devices for removing small negatively charged molecules from a biological sample mixture that uses a solid-phase extraction material that includes a hydrophilic solid support at least partially embedded within a hydrophobic matrix....http://www.google.de/patents/US7347976?utm_source=gb-gplus-sharePatent US7347976 - Methods and devices for removal of organic molecules from biological mixtures using a hydrophilic solid support in a hydrophobic matrix
