an endotoxin binding material affixed to a support is disclosed . one embodiment is a matrix material capable of binding endotoxins and comprising a polar , water - insoluble , high molecular weight polymer support to which is attached groups which adsorb endotoxin molecules . the groups comprise bifunctional aliphatic molecules , one end of which is bound to the support , the other end of which is bound to an aryl molecule . the invention has utility in the removal of endotoxins from biological fluids and other solutions and for concentrating endotoxins so that they may be subsequently detected and quantified .