Patent ID: 8753897

Claim:
A method of fractionating or separating very low molecular weight components from a fluid sample, said method comprising the steps of: (a) providing a fluid sample comprising a first component consisting of molecules having a molecular weight no higher than 20 kDa and a second component having a molecular weight higher than 20 kDa; (b) providing a substrate comprising a nanoporous material, wherein the nanoporous material comprises pores with a defined specific pore size that allows the entry of molecules of the first component and retains substantially all molecules of the first component and excludes substantially all molecules of the second component; (c) exposing the substrate to the sample for a first period of time sufficient for the first component to penetrate a nanoporous surface of the substrate and enter into the pores of the nanoporous material while the second component does not penetrate the nanoporous material; (d) washing the substrate for a second period of time sufficient to displace the second component from the substrate without removing the first component from pores of the nanoporous material; (e) exposing the substrate to a solvent to extract the first component from the pores substrate; and (f) analyzing a fraction of the first component that penetrated and entered into the nanoporous material.