Patent ID: 7901558

Claim:
A two-dimension method for separating compounds present in a sample mixture, the method comprising in the following order: (a) separating the compounds in a first-dimension gel strip on the basis of isoelectric points, at least partially contacting the first-dimension gel strip with a gel solution and performing a polymerization to obtain a second-dimension gel in contact with the first-dimension gel strip, (b) contacting the separated compounds in the first-dimension gel strip with a first buffer solution comprising sodium dodecyl sulfate (SDS), (c) applying an electric field to electrokinetically migrate the SDS into and through the first-dimension gel strip in a flow direction from a backside to a frontside of the first-dimension gel strip toward the second-dimension gel, wherein the separated compounds complex with the migrating SDS to form SDS-complexed compounds and are at least partially compacted at the front side of the first-dimension gel strip before migration into the second-dimension gel, and (d) separating the SDS-complexed compounds in the second-dimension gel on the basis of molecular size, wherein the SDS in the first buffer solution is present at a concentration higher than in a running buffer used in the second dimension.